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DIY Stompboxes => Building your own stompbox => Topic started by: pinkjimiphoton on January 30, 2019, 03:25:42 PM

Title: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 30, 2019, 03:25:42 PM
hola mi amigos,

sooo in the 70's, i used to rock an ancient ovation preamp with top boost, fuzz, reverb and tremolo.

nostalgia dictated i find another, which i did. sadly, it arrived DOA yesterday, but the guy i got it from, one mr v from trading musician in seattle was a total gem and took care of me with it. i endorse this cat, good dude.

anyways, i took it apart last nite to try and sort it all out, and its kinda cool, modular like an old haynes jazz king II or your average tower computer... all circuits on their own cards, wired in parallel to the power supply, and all summed to a mixer stage <which is what has failied, but i plan on repairing>

these things sound GREAT into a clean fender. turn the amp volume down, crank the preamp, and bring up the volume till its loud n proud... add reverb trem, top boost and a touch of fuzz.... heavenly. when it works.

this one's sick. trying desperately to find a schematic for it with little success.

but anyways, i pulled the fuzz card, and was thinking it may be fun for us fuzzaholics <if there's any left out there> to play with.

my eyes are plain too damn bad these days to do much sadly. even with glasses and meds everything is fuzzy as hell.

so i figure i'd scan the suckers trace side and post it, and then write in the components and values. maybe even improve upon them some...
its a 2 x bc109 fuzz, so it should be something that COULD sound good.

as i recall, it was kinda chewey like a buzzaround, but 40 years later,  my ears may have gotten a bit more refined.

anyways, be back shortly with pics,. any help i'd be very grateful!

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: ElectricDruid on January 30, 2019, 06:07:02 PM
Well, I've never heard of it, so I'm interested to have a look at least! I'd love to see some pics.


Tom
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Marcos - Munky on January 30, 2019, 06:33:49 PM
I'm interested too!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 30, 2019, 09:58:05 PM
sorry brothers
not feeling so great today, had to go take a chill for a while.
gonna go down stairs to the dungeon and get some pics etc, will be back shortly. too cold to stay down there tonite!!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: digi2t on January 30, 2019, 10:41:35 PM
Ovation K6001?

Popcorn is in the microwave.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on January 30, 2019, 10:43:09 PM
Quote
not feeling so great today, had to go take a chill for a while.
Take it easy.

Your description sounds a lot like this,
http://www.ovationtribute.com/Ovation%20Amps/Ovation%20K-6100%20Amp/Ovation%20K-6100.html
http://www.ovationtribute.com/Catalogues/Amplifiers%20Owner%20Manual/K-6001/K-6001.html
some others,
http://www.ovationtribute.com/Amplifiers%20Owner%20Manual.html

Unfortunately no schematics even for the amp.

Quote
Ovation K6001?
Just found that too.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 31, 2019, 12:37:52 AM
damn dyslexic atheism strikes again ? beats me.

i took it apart. interesting way it was done, very clean and very easy to follow and work on,
even for a moroon like me.
got pix of some of it so gimme a sec here....

still waiting... lol

ok, first, the fuzz.

the top of the board. i have yet to write down the values, i hope to do so in the morning when i have good light to see. the leftmost trace is partially obscured, but if ya follow the line of my thumb it actually lines up. weird. ;)


(https://i.postimg.cc/75MP92Z3/fuzz-top.png) (https://postimg.cc/75MP92Z3)

here's the trace side


(https://i.postimg.cc/mtWtSRSG/fuzz-bottom.png) (https://postimg.cc/mtWtSRSG)


here's the trace side reversed in case you're like me and like to draw the circuit onto the reversed trace to see what goes where. long story, but memory of a lobotomized circus flea here. so for me, it's easier to visualize


(https://i.postimg.cc/rD3mKksb/fuzz-traces-reversed-xray.png) (https://postimg.cc/rD3mKksb)


the transistors, at least the one i can see under the goop appear to be bc109 c's
orange drop is .33uF @75
other caps are chocolate colored blobs, all .001 @100v which is likely why the fuzz sounds so bloody @#$%ing atrocious.
outer foil of the first two facing the plug in area, marked by orange marks. <looking at top of board with them on bottom left> third .001 outer foil facing upwards.
the orientation matters, cuz if the outer foil isn't on the outside, you get a martian/mexican/alien/nsa radio reciever instead of a shield.
it's entirely possible they f'd this up. just presenting the facts, folks.

ANYWAYS...
here's the values i believe i see, but i don't see very well these days without really bright light.



(https://i.postimg.cc/34tJQ4ys/with-values.png) (https://postimg.cc/34tJQ4ys)

the fuzz is supposed to work on both channels, so i am imagining its a stereo in with a mono out. its freekin weird. the amp will run with ANY of the cards pulled. seriously.

yet somehow, both channels run thru the fuzz.
i believe the outermost trace around the board is ground, i gotta take voltage measurements and stuff still. right now i'm just looking.

this, however is what's killed the damn thing, either the transistor, and unmarked button one, or some of its peripherals have died, messing up the preamp unless i'm mistaken.

the "channel two" only output works loud n proud.
the paralleled channel out put is about 12 db below unity with the thing pegged, which is NOT right, and appears to come right off those output jacks to the suspect transistor. this thing uses them same gawdawful spade connectors as the ludwig did, but at least are soldered on and heavily.


(https://i.postimg.cc/Q9QYF1gz/Pic-01302019-007.jpg) (https://postimg.cc/Q9QYF1gz)

(https://i.postimg.cc/kR71KGfg/Pic-01302019-008.jpg) (https://postimg.cc/kR71KGfg)

(https://i.postimg.cc/c6c5Z7Lg/Pic-01302019-009.jpg) (https://postimg.cc/c6c5Z7Lg)

(https://i.postimg.cc/KRvpYK19/Pic-01302019-010.jpg) (https://postimg.cc/KRvpYK19)

(https://i.postimg.cc/9z2NvgCH/Pic-01302019-011.jpg) (https://postimg.cc/9z2NvgCH)

(https://i.postimg.cc/qzbb6knp/Pic-01302019-012.jpg) (https://postimg.cc/qzbb6knp)

#fuzzygoodness

(https://i.postimg.cc/LnbD6xKX/Pic-01302019-005.jpg) (https://postimg.cc/LnbD6xKX)

(https://i.postimg.cc/cKqcf6JG/Pic-01302019-006.jpg) (https://postimg.cc/cKqcf6JG)

a couple random pics


(https://i.postimg.cc/5HxXcM7F/Pic-01292019-001.jpg) (https://postimg.cc/5HxXcM7F)

(https://i.postimg.cc/f3BJDgpq/Pic-01302019-001.jpg) (https://postimg.cc/f3BJDgpq)

(https://i.postimg.cc/vgTDBtdY/Pic-01302019-002.jpg) (https://postimg.cc/vgTDBtdY)

(https://i.postimg.cc/mznkF1bQ/Pic-01302019-004.jpg) (https://postimg.cc/mznkF1bQ)

the first two show where the preamp card mount was snapped off the front panel by the fedex monkeys, pointing at it with my pointy thing.

anyways.. i'm all in, its 1234 am here so i am outta here... let me know your thoughts! its entirely possible i've messed up some values, i cannot tell white and yellow or green and blue apart very well anymore unfortunately. 

check in tomorrow... peace!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 31, 2019, 01:32:12 AM
this is a composite very badly done, but hopefully its right


(https://i.postimg.cc/F1fY3vYh/fuzz-layout-1.png) (https://postimg.cc/F1fY3vYh)

duh. brain dead. i think i labeled the orange bands + on the earlier pic, but its actually gotta go to ground usually. sorry for the confusion!

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: anotherjim on January 31, 2019, 05:05:07 AM
Can't say anything to help, but I am being educated. I had no idea the Ovation brand existed before those boat-back acoustics spawned a generation of amplified whiners in the '70's ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: digi2t on January 31, 2019, 05:46:40 AM
JAM Industries, which is located about 20 minutes from my house, is the Canadian distributor and repair facility for many instrument manufacturers, including Ovation. I've sent them an email requesting any shop literature they may have. We'll see what pans out.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 31, 2019, 08:31:56 AM
Can't say anything to help, but I am being educated. I had no idea the Ovation brand existed before those boat-back acoustics spawned a generation of amplified whiners in the '70's ;)

lol oh, i dunno, i was always more of a les paul and marshall guy back then.

still like my reefer, too. ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 31, 2019, 08:40:10 AM
dino,
if you can find anything at all, you are even more godlyke than we thought.

i'm imagining SAMS photofact sheets somewhere festering in like, a 90 year old dude's repair shop maybe.
this thing i believe is from around 1968 or 69. series a it says on it, the serial number is kinda cryptic so just a guess as info is impossible to find.

i can see the colors clearer now with the sunlight streaming on it... i got one resistor wrong last nite, corrected below


(https://i.postimg.cc/rz0VkV8P/with-values-corrected.png) (https://postimg.cc/rz0VkV8P)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: digi2t on January 31, 2019, 10:53:15 AM
JAM Industries was a no go for "we don't share blablabla" reasons.

Contacting Ovation directly.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 31, 2019, 11:04:35 AM
don't bother.
ovation was here in new hartford, ct.
when fender closed them a couple years back, they threw away all the shit from the entire ovation history. the factory had spare parts, pickups, amp parts etc. all gone. all paperwork gone, too.

dumbasses.

there's no one to contact, unless somehow ya can find one of the engineers who designed, but that was close to 50 years ago now, so odds aren't good, sadly.

my late brother ed had some stuff a friend had fished out of one of the dumpsters, got a whole "little dude" 100 watt guitar combo ... but it was in pieces. cabinet, speakers, amp, preamp, all taken apart and separate. resurrected it a few years ago.. but man, everything from there is gone, dino.

fender, who owns ovation now, has nothing.  frankly these days, i'd be amazed to get someone to answer the phone who isn't speaking dude speak.

gibson is THE WORST for crappy support these days. but fender isn't like it was, either.

i contacted a guy about SAMS photofacts, to see if he has anything from ovation, we'll see. a lot of times missing info can ONLY be found in those it appears... service techs would buy subscriptions to them, and they'd have all kindsa stuff in them for things you can't find elsewhere.

its possible i think to fix this, just by tracing it. but man, a schematic would indeed be awesome!!!

question for you smarter guys...

if ya put two circuits in parallel with each other, will you lose half the output? perhaps this thing DOES work and i'm just forgetful...

but messing with it, once in a while i could get the "quiet" outputs to unleash one hell of a roar which is more what i expected from my memories. just a split second here or there.. so assuming either the mixer board is damaged, or something is shorted from getting banged in transport. gonna take quite a bit of looking i have a feeling. but the GOOD thing is both preamp boards and all the module boards all appear to be working. so its either wires, connectors, or that one board.

the fuzz will be cool to mess with hopefully. looking at it, it looks like they f'd up and put the wrong value caps in... 10n maybe, but 1n? no way. i bet they were supposed to be 10n or 100n.

and of course, i think if the fuzz can be improved upon, well... thats just icing on the cake!!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Mark Hammer on January 31, 2019, 11:11:49 AM
The fuzz is a two-transistor circuit, going by the pic.  Just how different could the topography be from the various 2-transistor fuzzes we are all familiar with?  It's either gonna be something like a Fuzz Face, something like a Fuzz-Rite, or something like a Boss-Tone right?
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 31, 2019, 11:34:21 AM
probably, mark

but hard to tell cuzza the miles of cable connecting stuff, i am gonna have to trace where each of the inputs at the bottom of the board go to in the unit i think.

it MAY be two ONE transistor fuzzes summed to mono... each channel shares the fuzz as far as i remember, and it looks like it has two independent inputs to me, that then get summed and output thru the sprague cap.

it doesn't sound like a fuzzface, or a bosstone or a fuzzrite. more like a severely distorted treble booster kinda.  reminds me almost of the distortion in a jc120. sounds ok in moderation when the amp is cranked, sounds like poopy death by itself with the things volume turned low.

misbiased 2 transistor 60's fuzz, absolutely.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Marcos - Munky on January 31, 2019, 01:08:49 PM
I did a quick and dirty drawing on DIYLC:
(https://i.postimg.cc/4Hf7sYxh/ovationfuzz.png) (https://postimg.cc/4Hf7sYxh)

And here's what I got:
(https://i.postimg.cc/y3j1PnBD/ovationfuzz.jpg) (https://postimg.cc/y3j1PnBD)
The numbers are the tracks from left to right, and my guesses on what they are.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: digi2t on January 31, 2019, 01:27:32 PM
Ovation replied promptly. No info available.

 :icon_frown:
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 31, 2019, 03:23:08 PM
dino,
let me put it this way... bob widlar woulda tore ovation a new one over this ;)

munky, looks cool!! i am gonna check it out. hope to breadboard maybe this weekend,
and will try and get the fuzz level pot value and voltage it runs on then as well. the two open pads are i believe for the fuzz softness control mentioned in some of the other models.

wow, interesting permutation! i gotta look closer. i CAN tell ya that its all color codeds, so we should be able to figure it out once i get a chance to get to it. your interpretation is likely right, yet almost opposite of mine. but i will defer to your experience and ...

where's that popcorn, dino?

 :icon_mrgreen:

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 31, 2019, 03:24:10 PM
hmmm... maybe the parents, kaman aerospace may have archives?
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on January 31, 2019, 04:10:31 PM
It's a cool looking thing.

Quote
The numbers are the tracks from left to right, and my guesses on what they are.
I did a hand drawing last night but didn't get a chance to draw it up.
I got the same as Marcos-Munky.

As far as the part values go I was thinking:
- 180k not 680k
- 3.9k not 1.5k

What stage comes first and how they connect together to the other boards is a mystery.
So too is the pot connections.

That unit only has a Fuzz-Blend pot.   So obviously a single pot like that  cannot resolve all the unknown connections.

So thinking bit outside of the box:

I have a feeling some of those 1n caps connect to the two Top Boost switches.   [Doubt it, see EDIT 1] 

There's also the possibility some of the connections aren't used.   One of the other amp models (K-2002) has two Fuzz pots: Fuzz Blend and Fuzz-Shift.   The same board might be used for both amps so some connections might only used on that other model.

Lasty, there's a preamp section with Bass an Treble controls.   That section is likely to have some gain so the Fuzz board might not Fuzz unless it has the gain from that first stage present.

The only way to resolve all this is to trace through the wiring in the unit to know which Fuzz Wire numbers goes to which board and which pot, and which Fuzz Wire numbers are unused.
------------------------
EDIT 1:
Looking at the manual,
http://www.ovationtribute.com/Catalogues/Amplifiers%20Owner%20Manual/K-6001/K-6001.PDF

The way the TOP BOOST functions are described it seems unlikely these have anything to do with the Fuzz.
For a start, there's two switches which work independently on each channel.

Quote
the fuzz will be cool to mess with hopefully. looking at it, it looks like they f'd up and put the wrong value caps in... 10n maybe, but 1n? no way. i bet they were supposed to be 10n or 100n.
So ... maybe !
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on January 31, 2019, 07:24:36 PM
It's a cool looking thing.

Quote
The numbers are the tracks from left to right, and my guesses on what they are.
I did a hand drawing last night but didn't get a chance to draw it up.
I got the same as Marcos-Munky.

asap i will trace what goes where. there is only one fuzz pot, it has a switch on it. these things are weird. REAL weird!!!

Quote
As far as the part values go I was thinking:
- 180k not 680k
- 3.9k not 1.5k

i can verify the values on the resistors too, but the values posted most def are right according to the color bands. the suck thing is i can only really see that shit in super bright light now.


Quote
What stage comes first and how they connect together to the other boards is a mystery.
So too is the pot connections.

all stages are in parallel bro.
if ya pull one preamp card, the rest of the circuit still functions. if ya pull the fuzz, reverb, tuner, or trem boards, it still functions. it all sums together at that mixing board in the back, and then is output to the jacks from what i could see yesterday.



Quote
That unit only has a Fuzz-Blend pot.   So obviously a single pot like that  cannot resolve all the unknown connections.
Quote

nope. pretty sure the extra pads were for the extra functions this particular unit doesn't have <yet>

Quote
So thinking bit outside of the box:

I have a feeling some of those 1n caps connect to the two Top Boost switches.   [Doubt it, see EDIT 1] 

top boost is functional and independent of the fuzz completely. you can pull the fuzz board out and the top boosts still work normally.


Quote
There's also the possibility some of the connections aren't used.   One of the other amp models (K-2002) has two Fuzz pots: Fuzz Blend and Fuzz-Shift.   The same board might be used for both amps so some connections might only used on that other model.

same board was definitely used on both models. but its fed by each preamp as far as i can tell, so two inputs to one output.
but its a "paralell" fuzztone, its not mixed in series with the signal, its brought up in parallel with it i think.


Quote
Lasty, there's a preamp section with Bass an Treble controls.   That section is likely to have some gain so the Fuzz board might not Fuzz unless it has the gain from that first stage present.

yeah, the preamps are supposed to be loud as hell. the single pre from the channel two only jack is LOUD AS HELL. the goal is to get the parallel channel output loud as hell too...

or do parallel channels cut the signal in half? i don't know how that works, but i expect it should be about the same like AnyFenderAmp kinda


Quote
The only way to resolve all this is to trace through the wiring in the unit to know which Fuzz Wire numbers goes to which board and which pot, and which Fuzz Wire numbers are unused.


agreed.
gotta gig tonite but will be on it asap

Quote
------------------------
EDIT 1:
Looking at the manual,
http://www.ovationtribute.com/Catalogues/Amplifiers%20Owner%20Manual/K-6001/K-6001.PDF

The way the TOP BOOST functions are described it seems unlikely these have anything to do with the Fuzz.
For a start, there's two switches which work independently on each channel.

Quote
the fuzz will be cool to mess with hopefully. looking at it, it looks like they f'd up and put the wrong value caps in... 10n maybe, but 1n? no way. i bet they were supposed to be 10n or 100n.
So ... maybe !

hahahah yeah, ovation was overconcerned with TREBLE RESPONSE. i can't see a 1n cap allowing enough WOOOOOOF thru to actually fuzz ;)

betting 100n will sound way better in the end ;)

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Marcos - Munky on January 31, 2019, 07:31:24 PM
Quote
What stage comes first and how they connect together to the other boards is a mystery.
So too is the pot connections.

all stages are in parallel bro.

I think what Rob means is looking just at the fuzz, not at the whole unit. There's 2 transistors, so 2 stages. On the schematic I drew, I guessed where's the input and where's the output, and so I guessed which one is the 1st stage and which one is the 2nd stage. But I may have guessed wrong and they're actually reversed.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on January 31, 2019, 08:03:50 PM
Quote
i can verify the values on the resistors too, but the values posted most def are right according to the color bands. the suck thing is i can only really see that shit in super bright light now.
OK cool.  The 680k looks really high to me in that position (doesn't mean it's not correct).

Quote
all stages are in parallel bro.
Ah, OK.  That puts a different spin on things for the fuzz.

Quote
same board was definitely used on both models. but its fed by each preamp as far as i can tell, so two inputs to one output.
but its a "paralell" fuzztone, its not mixed in series with the signal, its brought up in parallel with it i think.
OK got it.

Quote
but i expect it should be about the same like AnyFenderAmp kinda
I'd expect the same.

Quote
hahahah yeah, ovation was overconcerned with TREBLE RESPONSE. i can't see a 1n cap allowing enough WOOOOOOF thru to actually fuzz ;)

betting 100n will sound way better in the end
Since the distortion is in parallel, maybe their thinking was to blend in the upper frequency dirt with the blend control.  The lows coming from the clean path.   I suppose it's more a concept than what would sound better.

Quote
I think what Rob means is looking just at the fuzz, not at the whole unit. There's 2 transistors, so 2 stages. On the schematic I drew, I guessed where's the input and where's the output, and so I guessed which one is the 1st stage and which one is the 2nd stage. But I may have guessed wrong and they're actually reversed.
Yes I was thinking just that.

The whole two-stage thing could go anywhere.   Like it could be two parallel circuits for all we know!   The missing emitter resistor seems to point to a pot to ground being there.   If the emitter fed the Fuzz-blend pot and the wiper goes to the mixer that make sense for the emitter.  However it doesn't make sense for the two(!) connections on the collector - where do they go?

Very confusing.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Marcos - Munky on January 31, 2019, 08:13:33 PM
I guess we'll need pictures of the main board, where the cards are attached. Then we'll be able to get those connections.

Edited: looking again at the pictures you took, looks like there's no "main board", just wires. So we'll need to trace those wires.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 01, 2019, 02:26:48 AM
yeah, its all like connectors for inside a tower computer, where ya plug differnt cards into it... i forget the nomenclature.
its gonna be a LOT of tracing. that suckers wired like an electric organ!! its a real shame no schematics seem to exist. a testament to sucky tone? lol

and yes, the fuzz is kinda blended in the background, just adding bite to the preamps. the preamps SHOULD have ample gain, but its gotta be that one mixer stage thats messed up.

i pulled the cards for the preamps, cuz they were identical, and the problem stayed either way, so i know the preamp cards are working, the tremolo is working, the topboost is working, the reverb is working on both channels only with the parallel outputs, which isn't right. even the "e" tuner oscillator card is working! its really cool, each part is its own discrete circuit wired in parallel so if one part goes down the rest keeps working.

hopefully tomorrow or saturday i can get some quality bench time with it and my meter.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 01, 2019, 02:56:03 AM
Quote
but its gotta be that one mixer stage thats messed up.
There could be more opportunities for stuff-ups.

The signal flow isn't clear to me:
- If the Fuzz/Reverb are all parallel then the mixer must be post everything.    I can't imagine the Tremolo being parallel (?) so that would be post the mixer (?)
- *If* the main mixer is post everything  then the two channels must be mixed together before the Reverb and before the Fuzz.   Then the combined signal would then need to be split-off to the Reverb and the Fuzz.
- The outputs of the Reverb and Fuzz would then be mixed with the output of each channel.
- If there's extra mixing and splitting going on, the fault could occur in the earlier stages.

The more I think about it more confused I get with option overload.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 01, 2019, 11:26:51 AM
Quote
but its gotta be that one mixer stage thats messed up.
There could be more opportunities for stuff-ups.

everything else is working.


Quote
The signal flow isn't clear to me:
- If the Fuzz/Reverb are all parallel then the mixer must be post everything.

yes, exactly. the only thing NOT in parallel, its hard wired to the chassis, and the only part NOT on a plug in card.

Quote
   I can't imagine the Tremolo being parallel (?) so that would be post the mixer (?)

no, you can pull the entire tremolo card, and the thing still works. its not post mixer, its before it. i told ya this thing is weird. ALL you need working to get sound to pass thru is ONE of the preamp cards.
you can make it work with the reverb other channel, fuzz, tuner or tremolo boards pulled. seriously.


Quote
- *If* the main mixer is post everything  then the two channels must be mixed together before the Reverb and before the Fuzz.   Then the combined signal would then need to be split-off to the Reverb and the Fuzz.

nope. all that shit is BEFORE the mixer board. the last thing in line is the mixer board before the outputs.
remember, the reverb is switchable on/off for each channel, so it obviously is NOT gonna be dependent on being AFTER everything. this is NOT a fender style amp at all. like i said, parallel. they even brag/rave about it in their literature. it was designed so that if any card went down, the rest would still function. the fuzz is universal to the two channels, as is the reverb... tho the reverb has individual controls for off n on, it only has ONE mix control. the fuzz is always on once ya click the switch on the pot, and turn it up.

in order, from right to left from the back, you have channel one, channel two, then the fuzz and reverb boards are next, facing each other mirrored, then the tuner board, then the tremolo board. all of these are individual boards with computer style plugs that they plug into.
all the pots and switches mount to the front face of the chassis by flying leads.

the mixer stage is the very LAST PART of the entire assembly, and it has both channels and the reverb (not sure on the reverb yet) enter it, and off the back, there is one out put for channel two only, and one output with two jacks of the two channels in parallel. the second channel has a switching jack that  splits the two outputs, which is the  purpose of the mixer stage apparently. it runs on one transistor and a couple passives. there are pictures of it posted already earlier in the thread... there are 4 wires coming off the top, to the output jacks, and all the stuff going in is along the bottom edge

here's the mixer stage i just described. last thing before the output jacks. this is where the entire unit is f'n up.
(https://i.postimg.cc/0b6yQqDz/Pic-01302019-007.jpg) (https://postimg.cc/0b6yQqDz)

(https://i.postimg.cc/mPCZYNdR/Pic-01302019-008.jpg) (https://postimg.cc/mPCZYNdR)

(https://i.postimg.cc/cKWxXgj3/Pic-01302019-009.jpg) (https://postimg.cc/cKWxXgj3)

(https://i.postimg.cc/JyQ1g7V2/Pic-01302019-010.jpg) (https://postimg.cc/JyQ1g7V2)


Quote
- The outputs of the Reverb and Fuzz would then be mixed with the output of each channel.

in parallel, not series.

Quote
- If there's extra mixing and splitting going on, the fault could occur in the earlier stages.

it can't. is you use the summed outputs, the thing works exactly as its supposed to, all the other cards are working, as can be proven by simply pulling them and putting them back in, as i said. the problem is the output is WAY below unity. the last thing before the outputs is... again... the mixer stage.

the channel two output also comes from there, but appears to be a straight shot thru. when you use the channel two out, it splits the channels to  the two sets of outputs, and the channel two only output is LOUD N PROUD the way it SHOULD be... but the reverb doesn't work, which it should. the reverb appears to also hook to this mixer stage.

so... all the channels cards work. the fx cards work. the tuner card works. there are no other circuit board in the unit other than the output board at the very end.

if all the circuits work at the for all intents mono output, and i can again, switch the preamp cards for each other, and both work identically regardless of which is which, obviously the preamp cards are working. the problem, much like in a tube amp, stays with the socket, not the card.
the reverb is working, or there would be no reverb.
the trem is working, or there would be no trem
the tuner part is working as well.

all thats left is that mixer stage, and one side is obviously not working right. that is also the side with the unmarked button transistor that connects to the parallel's output jacks with the low volume, and sounds like playing thru a circuit with a blown transistor. lower volume, more distortion than it should have... but it still passes signal. years ago, i had an old kustom i used as a preamp.. the power amp was cooked, so i took the line out/slave out from it and used it as a preamp for my jcm800 so i had more drive, and reverb and tremolo.
the amp still functioned, and added a good bit of overdrive... but less than unity gain. same exact sympton here bro.


Quote
The more I think about it more confused I get with option overload.

hahah.... welcome to MY world.
i assure ya, i spent hours headscratching to figure out what and where the fault is. if it looks like a duck and acts like a duck, its probably not the president. <at least not normally>

this thing is weird, i told ya!!

anyways, process of elimination, the ONLY thing left in the end that can be @#$%ing up is that mixer board at the end. i think its just supposed to be a buffer to stop crosstalk between the channels most likely, which is probably why its just a single transistor.

i couldn't make this stuff up if i tried . seriously!!!!

i would gladly send it to you if you really want to see for yourself. its as @#$%ed up as a soup sandwich. but when its working again, it will be cool. ;)
its literally those 6 cards, the mixer stage, a bunch of switches and pots and an ass-load of wiring.



Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 01, 2019, 12:43:38 PM
chassis layout
(https://i.postimg.cc/XrjVB2HC/chassis-layout.png) (https://postimg.cc/XrjVB2HC)


mixer board front. those two switches are the reverb off and on for the two channels, they are part of the mixer board. the left side of the board is where the summed output feeds from.

(https://i.postimg.cc/Lnhccrbv/mixer-board-front.png) (https://postimg.cc/Lnhccrbv)

the back of the mixer board.  don't have it in front of me, so don't remember which wires were hot and which ground, but i do recall brown and blue go straight from this board to the channel two only output.

red and black wires to the right go directly to summed channel output. ya plug in there to drive up to two amps in parallel, or split off the channel two to be independent for stereo applications.

(https://i.postimg.cc/1g4JWq5z/mixer-board-back.png) (https://postimg.cc/1g4JWq5z)

this is where the rubber meets the road in terms of messing up. the channel two side looks like its a straight shot thru, to me, at least, and the both channels side appears to be buffered by that transistor and passively mixed (?)

and it appears that yes, the last thing before the mixer, or maybe AT the mixer, is the reverb returns. i'm imagining the reverb returns feed into it, and the trem modulates that board somehow, probably its input.

like i said, this thing is extremely weird!!!



(https://i.postimg.cc/cKWxXgj3/Pic-01302019-009.jpg) (https://postimg.cc/cKWxXgj3)

(https://i.postimg.cc/JyQ1g7V2/Pic-01302019-010.jpg) (https://postimg.cc/JyQ1g7V2)

(https://i.postimg.cc/TK3z6hYz/Pic-01302019-011.jpg) (https://postimg.cc/TK3z6hYz)

(https://i.postimg.cc/bZVKN8Zs/Pic-01302019-012.jpg) (https://postimg.cc/bZVKN8Zs)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 01, 2019, 06:15:06 PM
Quote
no, you can pull the entire tremolo card,
Perhaps the tremolo is done by the channel board?


Quote
it was designed so that if any card went down,
Yes, I read that in the manual.  It was like a concept behind the whole design
and perhaps explains why it has a certain weirdness.

Quote
the rest would still function. the fuzz is universal to the two channels, as is the reverb... tho the reverb has individual controls for off n on, it only has ONE mix control. the fuzz is always on once ya click the switch on the pot, and turn it up.
Funny thing is, when I read the manual it says Fuzz is only on Channel 2.    In  separate/stereo mode,  only channel 1 has reverb and channel 1 is louder than channel 2.  (See manual: page 3 point E and page 4 point S.)

Quote
the mixer stage is the very LAST PART of the entire assembly, and it has both channels and the reverb (not sure on the reverb yet) enter it,
The reverb must enter there somehow because the reverb switches are on that board.   It's not clear to me if the Reverb signals are Raw Reverb or Reverb+Channel already mixed together.

Quote
the channel two output also comes from there, but appears to be a straight shot thru. when you use the channel two out, it splits the channels to  the two sets of outputs, and the channel two only output is LOUD N PROUD the way it SHOULD be... but the reverb doesn't work, which it should. the reverb appears to also hook to this mixer stage.

I'm still struggling with the signal flow. Like where do the channel outputs go?  and where do the output jacks connect.

I've drawn a schematic of the mixer.   It might be a good start to help you piece the puzzle together with the unit in front of you.

(https://i.postimg.cc/HVYVHKVj/Ovation-K6100-Mixer-Board-V1-0.png) (https://postimg.cc/HVYVHKVj)

There's obviously some mods made with the resistors on the back of the board.  These look like factory mods.
However, the resistor on the emitter appears to be shorted out by a solder blob.    It might be worth checking this.  It could even be the fault which is stuffing up your mixer board.

(https://i.postimg.cc/V5jCzngZ/mixer-track-or-short.png) (https://postimg.cc/V5jCzngZ)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 01, 2019, 06:31:40 PM
Quote
no, you can pull the entire tremolo card,
Perhaps the tremolo is done by the channel board?

nope, the tremolo, other than the on/off switches and the depth and rate, is all on one pcb, the last one to the left in the pic above of the circuit cards. you can pull it completely out of the entire assembly, no connections, and the only thing that changes is the trem switches and knobs have no effect.



Quote
it was designed so that if any card went down,
Yes, I read that in the manual.  It was like a concept behind the whole design
and perhaps explains why it has a certain weirdness.[/quote]

definitely. they, i think, really thought their amps and stuff would take off, but nobody wanted crystal clear solid state with ample treble other than like, the partridge family ;)



Quote
the rest would still function. the fuzz is universal to the two channels, as is the reverb... tho the reverb has individual controls for off n on, it only has ONE mix control. the fuzz is always on once ya click the switch on the pot, and turn it up.
Funny thing is, when I read the manual it says Fuzz is only on Channel 2.    In  separate/stereo mode,  only channel 1 has reverb and channel 1 is louder than channel 2.  (See manual: page 3 point E and page 4 point S.)[/quote]

i will check... fuzz is definitely bleeding thru both channels, much stronger on channel 2. channel 2 is louder than channel one by way more than double. perhaps it IS working right for the most part and my memory is corrupted.
messing with it tho, i DID get it for a flash here and there to work as i recalled, with both channels working. i'll look at the manual, thanks rob, good call. maybe i'm just stupid. wouldn't be the first time! ;)





Quote
the mixer stage is the very LAST PART of the entire assembly, and it has both channels and the reverb (not sure on the reverb yet) enter it,
The reverb must enter there somehow because the reverb switches are on that board.   It's not clear to me if the Reverb signals are Raw Reverb or Reverb+Channel already mixed together.[/quote]

it seems to be each channel gets reverb, but only in the parallel mode where its suffering the big volume drop. since the only thing there is that board, seems the most likely culprit going by all the crap i learned reading jack darr columns forever ;)



Quote
the channel two output also comes from there, but appears to be a straight shot thru. when you use the channel two out, it splits the channels to  the two sets of outputs, and the channel two only output is LOUD N PROUD the way it SHOULD be... but the reverb doesn't work, which it should. the reverb appears to also hook to this mixer stage.

I'm still struggling with the signal flow. Like where do the channel outputs go?  and where do the output jacks connect.[/quote]

the output jacks connect to the mixer board, if ya look at the last pix i posted, you can see where the output wires are from the mixer board. the blue and brown are channel 2, the black and red channel 1 AND 2.



I've drawn a schematic of the mixer.   It might be a good start to help you piece the puzzle together with the unit in front of you.

(https://i.postimg.cc/HVYVHKVj/Ovation-K6100-Mixer-Board-V1-0.png) (https://postimg.cc/HVYVHKVj)[/quote]

dude... thanks!! that will definitely help!!!


Quote
There's obviously some mods made with the resistors on the back of the board.  These look like factory mods.
However, the resistor on the emitter appears to be shorted out by a solder blob.    It might be worth checking this.  It could even be the fault which is stuffing up your mixer board.

(https://i.postimg.cc/V5jCzngZ/mixer-track-or-short.png) (https://postimg.cc/V5jCzngZ)

i will look, that would likely explain it!! thanks rob for all the help and patience man! ;)
i will try and look tonite or tomorrow at it closely. and will post results.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 01, 2019, 07:22:57 PM
Quote
nope, the tremolo, other than the on/off switches and the depth and rate, is all on one pcb, the last one to the left in the pic above of the circuit cards. you can pull it completely out of the entire assembly, no connections, and the only thing that changes is the trem switches and knobs have no effect.
I was think more the lines that the tremollo board had the oscillator and depth control then the output of the oscillator fed back to the channel amps.   The channel amps would each have a way to do the gain variations (JFET, vactrol or whatever).

Quote
but nobody wanted crystal clear solid state with ample treble other than like, the partridge family
People soon learnt   ;D

Quote
i will check... fuzz is definitely bleeding thru both channels, much stronger on channel 2. channel 2 is louder than channel one by way more than double. perhaps it IS working right for the most part and my memory is corrupted.
I was getting desperate so I had to go to the manual.

Quote
it seems to be each channel gets reverb, but only in the parallel mode where its suffering the big volume drop. since the only thing there is that board, seems the most likely culprit going by all the crap i learned reading jack darr columns forever
OK.   I wonder where the switching is done in Stereo mode?  It's not like it has a lot of switching going on.  Maybe something on one of the output jacks.

Quote
the output jacks connect to the mixer board, if ya look at the last pix i posted, you can see where the output wires are from the mixer board. the blue and brown are channel 2, the black and red channel 1 AND 2.
When I was looking at it I wasn't sure if "channel 2 out" meant "the output of the channel 2 preamp" and the "channel 2 output jack".   The circuit doesn't yet make sense to me so it could be either of those in the fuzzy Ovation universe.

Quote
i will look, that would likely explain it!! thanks rob for all the help and patience man! ;)
i will try and look tonite or tomorrow at it closely. and will post results.
No problem.   Good luck, sometimes you just have to keep poking around with these things until you hit the jackpot.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: digi2t on February 01, 2019, 07:29:54 PM
Quote
but nobody wanted crystal clear solid state with ample treble other than like, the partridge family

My new sig line. Thanks bro!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 01, 2019, 07:37:55 PM
but nobody wanted crystal clear solid state with ample treble other than like, the partridge family

Treble, A conspiracy to stop Danny from being heard,
(https://d310t4ch0h19vs.cloudfront.net/5/4/1/8/5418_0054__20151015140312.jpg)

Signature Partridge family basses,
(https://www.talkbass.com/attachments/d3989941-650c-4a96-8329-8ab731f4bbc9-jpeg.2868315/)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 01, 2019, 08:03:17 PM
Quote
nope, the tremolo, other than the on/off switches and the depth and rate, is all on one pcb, the last one to the left in the pic above of the circuit cards. you can pull it completely out of the entire assembly, no connections, and the only thing that changes is the trem switches and knobs have no effect.
I was think more the lines that the tremollo board had the oscillator and depth control then the output of the oscillator fed back to the channel amps.   The channel amps would each have a way to do the gain variations (JFET, vactrol or whatever).

i can easily take pics of the tremolo board, and the channel boards, too if ya would like. hoping to get to beep out which wires go where anyways and write it down. everything appears to be on the trem board but the two switches and two pots.
did i mention this thing is weird?? ;)


Quote
but nobody wanted crystal clear solid state with ample treble other than like, the partridge family
People soon learnt   ;D[/quote]

yeah man, lsd25 has a strange effect on some people. its tough when ya smell the sound of purple. lol



Quote
i will check... fuzz is definitely bleeding thru both channels, much stronger on channel 2. channel 2 is louder than channel one by way more than double. perhaps it IS working right for the most part and my memory is corrupted.
I was getting desperate so I had to go to the manual.[/quote]

i've been chuckling about that for like, 20 minutes!!! lol
its entirely possible it works right and i just don't recall, as it was 1980 on my birthday the last time i used one of these!! long time ago!!! lol
back when the only effects i had were a kay fuzztone, a violet rams head big muff, a clone theory and a guild wahwha. oh yeah, and the marlboro quadra sound blender reverb/ "echo" / tremolo. back then <mighta been that lsd again> it was important for me to have that tremolo running at a different clock then the trem in my sunn 1200s stacks... it was cool, double outta sync tremolos are highly underrated!!! lol it was almost like a phaser and a reverse attack kinda sound. very trippy. or maybe it was that lsd. i dunno. surprised i survived the 60's. and the 70's. and the ... well.... lol

Quote
it seems to be each channel gets reverb, but only in the parallel mode where its suffering the big volume drop. since the only thing there is that board, seems the most likely culprit going by all the crap i learned reading jack darr columns forever
OK.   I wonder where the switching is done in Stereo mode?  It's not like it has a lot of switching going on.  Maybe something on one of the output jacks.[/quote] there's a switching jack on the channel two only output, and that jumpers over to the "mono" outputs. its a normally closed jack switch, so when its unplugged,  the reverb works on both channels, and both channels come out the mono outputs. when ya plug it in, it kills the reverb to channel two, and the volume goes WAY up.
so maybe it IS working.... again... and i am just a forgetful moron. my money's on the last one more by the minute lol



Quote
the output jacks connect to the mixer board, if ya look at the last pix i posted, you can see where the output wires are from the mixer board. the blue and brown are channel 2, the black and red channel 1 AND 2.
When I was looking at it I wasn't sure if "channel 2 out" meant "the output of the channel 2 preamp" and the "channel 2 output jack".   The circuit doesn't yet make sense to me so it could be either of those in the fuzzy Ovation universe.[/quote]

the channel 2 out is channel 2 only, with no channel one and no reverb. the dual "mono" outputs both preamp channels come thru with reverb. so i am suspecting from what you found it is indeed working, and i am just a fool with a bad memory ;)


Quote
i will look, that would likely explain it!! thanks rob for all the help and patience man! ;)
i will try and look tonite or tomorrow at it closely. and will post results.
No problem.   Good luck, sometimes you just have to keep poking around with these things until you hit the jackpot.
[/quote]

indeed! gonna check the mixer part, and see if that "blob" is actually a bridge. something tells me that may have been a fudge cuz they didn't think the parallel thing thru all the way ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 01, 2019, 09:19:44 PM
Quote
i can easily take pics of the tremolo board, and the channel boards, too if ya would like. hoping to get to beep out which wires go where anyways and write it down. everything appears to be on the trem board but the two switches and two pots.
did i mention this thing is weird??
If you want I can look at it.  Not sure if it will help fix the unit but it might help understand the unit.
Yes, it is weird.   Normally I can guess stuff but the whole topology of this thing is different so trying to guess comes up with 10 answers - totally useless!


Quote
its entirely possible it works right and i just don't recall, as it was 1980 on my birthday the last time i used one of these!! long time ago!!! lol
back when the only effects i had were a kay fuzztone, a violet rams head big muff, a clone theory and a guild wahwha. oh yeah, and the marlboro quadra sound blender reverb/ "echo" / tremolo. back then <mighta been that lsd again>
Do you remember if the tuner light was purple :icon_mrgreen:

Quote
it was important for me to have that tremolo running at a different clock then the trem in my sunn 1200s stacks... it was cool, double outta sync tremolos are highly underrated!!! lol it was almost like a phaser and a reverse attack kinda sound. very trippy. or maybe it was that lsd. i dunno. surprised i survived the 60's. and the 70's. and the ... well.... lol
I've never tried that.  Only tried the stereo left/right pan thing.

Quote
there's a switching jack on the channel two only output, and that jumpers over to the "mono" outputs. its a normally closed jack switch, so when its unplugged,  the reverb works on both channels, and both channels come out the mono outputs. when ya plug it in, it kills the reverb to channel two, and the volume goes WAY up.
so maybe it IS working.... again... and i am just a forgetful moron. my money's on the last one more by the minute lol

That makes a lot of sense.  Kind of lines up with the manual as well.

Quote
the channel 2 out is channel 2 only, with no channel one and no reverb. the dual "mono" outputs both preamp channels come thru with reverb. so i am suspecting from what you found it is indeed working, and i am just a fool with a bad memory

So does that.    So your memory is fine!

Quote
indeed! gonna check the mixer part, and see if that "blob" is actually a bridge. something tells me that may have been a fudge cuz they didn't think the parallel thing thru all the way

Maybe you should measure the +V rail on the mixer board and the voltage on the collector of the transistor.  That might help identify a problem with that stage.

I really think something *is* wrong.   It doesn't make sense that the channel 1 is so low.    It make even less sense when you look at the manual because it states channel 1 gain should be higher than channel 2 in stereo mode.    Channel 1 is coming off the output of Q1 on the mixer board.    The things that don't add-up all point to Q1.

FYI:  There's a bug on my mixer schematic. One of the 2x100k's  between the transistor and the switches should go to the other vertical strip of switch connections.  I'll fix it later.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 01, 2019, 10:53:10 PM
cool.... so yer saying the manual says i'm a moron, huh?? lmao!!

 :icon_mrgreen:

the purple kinda had lime green perimeters as i recall....

i think that transistor isn't working too. too sick today to venture to the dungeon, but hopefully tomorrow. thanks bro!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 01, 2019, 11:20:05 PM
found this, which i hadn't seen til now... it says what you said, rob.
only diff is that channel TWO is the louder of the two... not channel one.
really thinking i am whats wrong with the circuit! ;)


(https://i.postimg.cc/rR58JrW0/descrip.png) (https://postimg.cc/rR58JrW0)

it pretty much acts as described, other than channel 2 being louder, and it seeming to be totally castrated out of the parallel jacks.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 01, 2019, 11:27:22 PM
Quote
cool.... so yer saying the manual says i'm a moron, huh?? lmao!!

 :icon_mrgreen:
:icon_mrgreen: (No way I'd say that.)

Quote
the purple kinda had lime green perimeters as i recall....
(http://rlv.zcache.ca/purple_crazy_eyes_smiley_face_sticker-r298ea15c4ed8492e9354a0d97b27253c_v9wth_8byvr_512.jpg)

Quote
i think that transistor isn't working too. too sick today to venture to the dungeon, but hopefully tomorrow. thanks bro!
It's looking like that.  The DC rail and the collector voltage should give a hint of any problems.

Quote
found this, which i hadn't seen til now... it says what you said, rob.
only diff is that channel TWO is the louder of the two... not channel one.
really thinking i am whats wrong with the circuit! ;)

it pretty much acts as described, other than channel 2 being louder, and it seeming to be totally castrated out of the parallel jacks.
That's it, that's the part I read.
So it seems channel 1 is the problem.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 01, 2019, 11:42:10 PM
no, its not channel one, cuz ya can switch the preamp cards, and the problem stays with the socket, not the cards.
the only thing after them is... you guessed it... that mixer stage.
i will get at it tomorrow.
immune system is wiped out from one medical issue, which has led to a mrsa infection that is really kicking my ass.

thanks bro... more soon
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 02, 2019, 12:04:16 AM
Quote
no, its not channel one, cuz ya can switch the preamp cards, and the problem stays with the socket, not the cards.
the only thing after them is... you guessed it... that mixer stage.
From what I can see, the channel 1 jack connects to the mixer.  Yes?  It's the red wire on pin 3.

The mixer isn't one of the "amplicards" so if it fails it's "allowed" to fail.

Quote
i will get at it tomorrow.
immune system is wiped out from one medical issue, which has led to a mrsa infection that is really kicking my ass.

thanks bro... more soon
Take it easy.  Plenty of time to sort this stuff out.

I was thinking about the small caps on the Fuzz circuit.   The MOSRITE/FUZZRITE (originally from an amp) had small caps and a blend control.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 02, 2019, 12:36:22 AM
rob,
if you're still up, pour yerself a libation and grab some popcorn, i gotta LOTTA info coming.
but first, that solder bridge you thought you saw is indeed a solder bridge, its actually i think shorting the center of the voltage divider to the center of the transistor... i assume the b?... right to freekin ground.

also, fuzz pot is 50k. didn't say a or b on it,  so... assuming its linear by the way it seems to act.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 02, 2019, 12:45:37 AM
ok, i also traced out the wires to the mixer from the rest of the circuit, all the ones that go in along the bottom, viewed from the back.... it looks like they tried to get more gain out of it by tacking on those resistors, not realizing they'd shorted the dang transistor. i may be wrong.. gotta look in better light.

anyways, from left to right across the bottom

orange wire goes to channel 2 output switch, switch connects to tip when open, so normally closed.

dark brown wire goes to channel 2 tip

blue wire goes to reverb slot # 10, from left to right viewing the board from the component side

light brown goes to channel two volume #3 if looking from the back with the lugs up, on the right

black wire goes to the tuner on switch

three black wires on this one, to parallel out ground, reverb #12 socket and reverb pot ground, and both channels vol 1

red wire channel one pin 6 with card sideways, components to left and + voltage

purple reverb socket pin 8

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 02, 2019, 12:50:55 AM
Quote
if you're still up, pour yerself a libation and grab some popcorn, i gotta LOTTA info coming.
but first, that solder bridge you thought you saw is indeed a solder bridge, its actually i think shorting the center of the voltage divider to the center of the transistor... i assume the b?... right to freekin ground.

OK, so it is shorted.   It's basically shorting out the emitter resistor on the transistor.   You can see the "???" in that area of the circuit on my schematic.

I really don't now if it's part of the factory mods with those resistors, someone elses mods, or a mistake.    Shorting out the resistor will add more gain to the transistor *but* it will also change the bias points.   It is possible those resistors on the back of the board attempt to trim the bias point with the shorted resistor in place.   I really don't know what it *should* be.   BTW what is the transistor part number of the Mixer board?. I can work out  the expected bias voltages and you could check that by measurement on the circuit.

I don't know if I should be scared or what on the next drop  :icon_mrgreen:
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 02, 2019, 12:59:49 AM
Quote
if you're still up, pour yerself a libation and grab some popcorn, i gotta LOTTA info coming.
but first, that solder bridge you thought you saw is indeed a solder bridge, its actually i think shorting the center of the voltage divider to the center of the transistor... i assume the b?... right to freekin ground.

OK, so it is shorted.   It's basically shorting out the emitter resistor on the transistor.   You can see the "???" in that area of the circuit on my schematic.

I really don't now if it's part of the factory mods with those resistors, someone elses mods, or a mistake.    Shorting out the resistor will add more gain to the transistor *but* it will also change the bias points.   It is possible those resistors on the back of the board attempt to trim the bias point with the shorted resistor in place.   I really don't know what it *should* be.   BTW what is the transistor part number of the Mixer board?. I can work out  the expected bias voltages and you could check that by measurement on the circuit.

I don't know if I should be scared or what on the next drop  :icon_mrgreen:

it looks like they added them resistors to try and get it to bias, none of the transistors are marked that i can see. all of them are big buttons... the resistor to the left, looking from the back of the board is definitely bridged to ground.

asssssssss load of pics coming. crummy cheap phone pics, but if anything is interesting or helps make sense of this, hey, cool! ;)

stay tuned. may take two photo dumps to get 'em all lol

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 02, 2019, 01:13:28 AM
pics of all the cards, they all suck, of course, but just to give ya a feel for some of that ol "vintage prawn" thang... here goes.. lets see how many pics they'll let me add at once ;)

"e tuner (actually G tuner) " board

(https://i.postimg.cc/w7mRv9x3/Pic-02022019-001.jpg) (https://postimg.cc/w7mRv9x3)

(https://i.postimg.cc/V0bvdF82/Pic-02022019-002.jpg) (https://postimg.cc/V0bvdF82)

preamp channel 2, slightly differnt caps but the same board

(https://i.postimg.cc/bDZNBRsd/Pic-02022019-003.jpg) (https://postimg.cc/bDZNBRsd)

(https://i.postimg.cc/PLrqmHHW/Pic-02022019-005.jpg) (https://postimg.cc/PLrqmHHW)

reverb board

(https://i.postimg.cc/mzK2fFHj/Pic-02022019-006.jpg) (https://postimg.cc/mzK2fFHj)

(https://i.postimg.cc/V0MsYL98/Pic-02022019-007.jpg) (https://postimg.cc/V0MsYL98)

channel one board

(https://i.postimg.cc/bd2w0L7B/Pic-02022019-008.jpg) (https://postimg.cc/bd2w0L7B)

(https://i.postimg.cc/LJVXYXc4/Pic-02022019-009.jpg) (https://postimg.cc/LJVXYXc4)

tremolo board

(https://i.postimg.cc/bGCwg5YK/Pic-02022019-010.jpg) (https://postimg.cc/bGCwg5YK)

(https://i.postimg.cc/4Ywf40cm/Pic-02022019-012.jpg) (https://postimg.cc/4Ywf40cm)

solder bridge

(https://i.postimg.cc/4mkNWVZN/Pic-02022019-013.jpg) (https://postimg.cc/4mkNWVZN)

gutz


(https://i.postimg.cc/8jRk9cPd/Pic-02022019-014.jpg) (https://postimg.cc/8jRk9cPd)

(https://i.postimg.cc/jDRqbTLp/Pic-02022019-015.jpg) (https://postimg.cc/jDRqbTLp)

(https://i.postimg.cc/kRr9h30h/Pic-02022019-016.jpg) (https://postimg.cc/kRr9h30h)

(https://i.postimg.cc/2qKChB2Y/Pic-02022019-017.jpg) (https://postimg.cc/2qKChB2Y)

100uF @50v (x 2)

(https://i.postimg.cc/LYg2T6b1/Pic-02022019-019.jpg) (https://postimg.cc/LYg2T6b1)

10,000uF @ 150 <i think>

(https://i.postimg.cc/3Wp30NpM/Pic-02022019-020.jpg) (https://postimg.cc/3Wp30NpM)

switches

(https://i.postimg.cc/p9T2mBQk/Pic-02022019-021.jpg) (https://postimg.cc/p9T2mBQk)

(https://i.postimg.cc/xNKQwpYj/Pic-02022019-022.jpg) (https://postimg.cc/xNKQwpYj)

(https://i.postimg.cc/vcsbryL4/Pic-02022019-023.jpg) (https://postimg.cc/vcsbryL4)

power in and footswitch jack

(https://i.postimg.cc/PLPjX5hR/Pic-02022019-024.jpg) (https://postimg.cc/PLPjX5hR)

output jacks... channel 2 only to the left

(https://i.postimg.cc/PCfH7M7h/Pic-02022019-025.jpg) (https://postimg.cc/PCfH7M7h)


actual model #. the case its in says 6005 ;)

(https://i.postimg.cc/d7pKLcVt/Pic-02022019-026.jpg) (https://postimg.cc/d7pKLcVt)

crappy front panel shots

(https://i.postimg.cc/zHSmtLSV/Pic-02022019-027.jpg) (https://postimg.cc/zHSmtLSV)

(https://i.postimg.cc/BPG9B5Fr/Pic-02022019-028.jpg) (https://postimg.cc/BPG9B5Fr)

(https://i.postimg.cc/tZ6G6vsd/Pic-02022019-029.jpg) (https://postimg.cc/tZ6G6vsd)

(https://i.postimg.cc/K4nyvVSx/Pic-02022019-031.jpg) (https://postimg.cc/K4nyvVSx)


holy cow, information overload!!!! ;)

i will slap it back together enough to get voltages but i'm betting that bridge is the key to the whole mess.
thanks for the hang, man...
will check back in the ...umm, well, ...
tomorrow  :icon_mrgreen:

peace out!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 02, 2019, 02:20:56 AM
Awesome.

I think I've got brain fry now ...  Bzzzzt.


BTW, I checked the circuit biasing assuming the transistors are generic like 2N3904's.
I've assumed the emitter resistor is 22k.  I can't read it so well.
Results:
1) resistor on back of board + shorted emitter resistor --->  looks OK for supply > 20V
2) resistor on back of board + without shorted emitter resistor --->  biasing doesn't look so good!
3) no resistors on back of board + without shorted emitter resistor ---> looks OK for supply > 20V

Case (1), ie. as it is now, has a lot more gain than (3), ie no mods.

So the mods are probably OK and the bridge is probably intentional.

What doesn't make sense is why the gain is so low.  Maybe the transistor is stuffed!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 02, 2019, 12:29:52 PM
bzzzzzzt indeed!!!!

yeah, i will try and take a peek today to confirm,  but i'm thinking same thing, snuffed transistor.
in fact, i'm wondering if them resistors weren't a dodge to try and get it to pass signal with a roasted q.

i dunno about a 3904, its a really BIG button, about as big around as a sharpie.

i COULD desolder it and take it out and measure it. i am surprised there's no markings on it. but it appears to be the same transistor used on the tremolo card and elsewhere. if i have to, i can sacrifice one of the ones on the trem card to get the unit working, then replace with something more modern once i have some specs to deal with.

i think its fried too, and thats why there's such a discrepancy in volume. i'm also wondering if this may be the same unit i had all those years ago, as i seem to remember blowing it up in the studio and the guy running the place having to fix it.
memory is funny. once it starts, and the details start coming back... ya never know.

haha back then i had this modded big muff. the volume pot broke, so i replaced all three with 1 meg pots from radio shack. it was unstable and loud and in some setting unuseable. but boy, i loved that thing ;)

maybe thats how it got cooked..... the world may never know how many licks it takes to blow up an ovation!! lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 02, 2019, 04:19:50 PM
Quote
i'm wondering if them resistors weren't a dodge to try and get it to pass signal with a roasted q.
I thought that at first too.  It looks like a factory mod *except* the solder bridge.   If it's a factory mod the aim would be to increase the level a bit.

Quote
i dunno about a 3904, its a really BIG button, about as big around as a sharpie.
I only used that to get an idea of the bias voltages.  The gains of the big buttons aren't that different to lower gain generic transistors like the 2N3904's.  So I'm confident my numbers are fairly representative of the

The bigger buttons are the TO-105 package, some common NPN's were (there are others),
   2N3566 to 2N3568
   2N3641 to 2N3642
   2N3569

IIRC they are more like 2N2222's.

Quote
i COULD desolder it and take it out and measure it.
Upto you.  If you measure +V and the collector voltage of the mixer transistor it should show up any issues.

Quote
transistor used on the tremolo card
Honestly, to see the transistor is bung I'd be just putting in any old transistor.   If the +V rails is high, like 50V, you might need to consider the transistor voltage.   

Quote
i think its fried too, and thats why there's such a discrepancy in volume. i'm also wondering if this may be the same unit i had all those years ago, as i seem to remember blowing it up in the studio and the guy running the place having to fix it.
memory is funny. once it starts, and the details start coming back... ya never know.
At this point it's the only thing that makes sense.

If the temolo is only an oscillator board and the gain control is done elsewhere, it crossed my mind that it is possible the gain control element is stuffed and making the gain low.    Given we don't know intricacies of the wee beasty it is a possibility.    At this point I'm happy to pursue the simple theory that the transistor is stuffed  ;D

Quote
the world may never know how many licks it takes to blow up an ovation!! lol
;D   Soon those DSP/modelling amps will have note counters in there that expire and blow-up the amps.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 02, 2019, 10:04:58 PM
slept the damn day away again, if its warm enough downstairs i may go have a tinker and see what happens. i don't wanna leave it apart so long i forget how to reassemble it like i did with the maestro rhtym n sound thats been sitting, working, but disassembled pretty much for the last 5 years ;)

i am sure i have some old TIP style npn's that should handle 50v ok, but first i need to get some voltage measurements happening on all the cards, etc.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 02, 2019, 10:15:20 PM
I had a look at all those pics.  I've worked out a bit more but I've hit the same old brick-wall.   I don't know how the modules connect between themselves.

For the Fuzz, I've managed to get this,

(https://i.postimg.cc/TpB4s9g1/ovation-k6100-fuzz-MM-V11-2019-02-02-potsw.png) (https://postimg.cc/TpB4s9g1)

The blue input wire and yellow output wire stay connected.   The switch on the fuzz pot kills the first transistor by disconnecting the emitter.   The weird thing is the orange wire on pin 8 seems to go somewhere as well.   The orange wire has DC on it so it could upset something else.

For the tremolo:
- The board contains the LFO (sine-wave) and it has two funny looking devices which appear to be Opto's.
- The LFO is a phase-shift oscillator.
- From what I can see the output of the LFO (pin 5) feeds two transistors, one for each channel.  The output of those transistors drives the 2x Opto's.  The output is one the collectors.  One side of the opto's resistance connects to the emitter of the driving transistor - an odd connection.
- The "tremolo outputs" are more or less variable resistors that short the signal to ground.  These appear on pins 3 and 7 (counting the key hole).
- So... the signal doesn't pass *through* the tremolo board.
- The wiring for the tremolo has two yellow wire on one side and two white wire on the other side.
- I can see the tremolo switch wiring but I suspect the two "tremolo outputs" go to the tremolo switch.
  The switch are either in series with the "tremolo outputs", or, they short the "tremolo outputs" to ground.
- Anyway, as expected, pulling the board out will simply remove the "tremolo outputs" and the variable resistors to ground.

Where the tremolo is in the signal path I don't know.   You might be able to see where it goes from the two wires I mentioned.   The important thing is it is unlikely to cause the problem you are seeing.

For the mixer I'm not sure if,
- the blue wire on pin 8 goes to the fuzz board
- the orange wire on pin 11 goes to the CH2 output jack
- the brown wire on pin 7 goes to the CH2 output jack
- Also not sure where the purple wire pin 1 goes.  I think maybe to the channel 1

BTW, the Channel 1 and Channel 2 preamp boards seem to be slightly different.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 02, 2019, 10:17:28 PM
Quote
slept the damn day away again, if its warm enough downstairs i may go have a tinker and see what happens. i don't wanna leave it apart so long i forget how to reassemble it like i did with the maestro rhtym n sound thats been sitting, working, but disassembled pretty much for the last 5 years
If you need to rest you should do it.   I'm sure no one will mess with it in your electronics dungeon over the next week.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 02, 2019, 10:22:58 PM
Oh I forgot to mention the reverb.

It's the usual thing where you have a reverb tank drive circuit and recovery preamp.

From what I can see it is entirely mono.  No combining of channels 1 and 2, and no mixing.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 02, 2019, 10:37:01 PM
I had a look at all those pics.  I've worked out a bit more but I've hit the same old brick-wall.   I don't know how the modules connect between themselves.

For the Fuzz, I've managed to get this,

(https://i.postimg.cc/TpB4s9g1/ovation-k6100-fuzz-MM-V11-2019-02-02-potsw.png) (https://postimg.cc/TpB4s9g1)

The blue input wire and yellow output wire stay connected.   The switch on the fuzz pot kills the first transistor by disconnecting the emitter.   The weird thing is the orange wire on pin 8 seems to go somewhere as well.   The orange wire has DC on it so it could upset something else.

i will try and trace the socket to where it goes tonite. i think the description coming off the mixer board is in this post:

https://www.diystompboxes.com/smfforum/index.php?topic=121835.msg1147111#msg1147111


Quote

For the tremolo:
- The board contains the LFO (sine-wave) and it has two funny looking devices which appear to be Opto's.
- The LFO is a phase-shift oscillator.
- From what I can see the output of the LFO (pin 5) feeds two transistors, one for each channel.  The output of those transistors drives the 2x Opto's.  The output is one the collectors.  One side of the opto's resistance connects to the emitter of the driving transistor - an odd connection.
- The "tremolo outputs" are more or less variable resistors that short the signal to ground.  These appear on pins 3 and 7 (counting the key hole).
- So... the signal doesn't pass *through* the tremolo board.
- The wiring for the tremolo has two yellow wire on one side and two white wire on the other side.
- I can see the tremolo switch wiring but I suspect the two "tremolo outputs" go to the tremolo switch.
  The switch are either in series with the "tremolo outputs", or, they short the "tremolo outputs" to ground.
- Anyway, as expected, pulling the board out will simply remove the "tremolo outputs" and the variable resistors to ground.

i believe the trem switches just short to ground, and when they do, it lets the trem circuit short each channel to ground off and on. i will check and write the signal path down.
i gotta look closer at that board, i guess, i haven't cuz i've been focused on the problem.
some of the guys at the diy-audio forum think i should start by removing that bridge on the mixer board.

Quote
Where the tremolo is in the signal path I don't know.   You might be able to see where it goes from to two wires I mentioned.   The important thing is it is unlikely to cause the problem you are seeing.

the trem is the last card before the mixer... circuit flow is channels one and two in parallel, then fuzz, then reverb, then oscillator/tuner and finally trem... then the mixer and outputs.


Quote
For the mixer I'm not sure if,
- the blue wire on pin 8 goes to the fuzz board


see the listing of the wires, https://www.diystompboxes.com/smfforum/index.php?topic=121835.msg1147111#msg1147111
the blue wire does go to the fuzz board, pin 10

Quote

- the orange wire on pin 11 goes to the CH2 output jack
- the brown wire on pin 7 goes to the CH2 output jack


yes, you got it. thats exactly right

Quote
- Also not sure where the purple wire pin 1 goes.  I think maybe to the channel 1

purple wire goes to reverb socket pin #8

Quote

BTW, the Channel 1 and Channel 2 preamp boards seem to be slightly different.

yeah, i think they used slightly different caps etc to make it a bit "hotter"...
but either preamp board will work pretty much identically in either preamp socket.

remember, their stuff was pretty vegematic, they'd use exactly the same thing with a bunch of different names for different applications. ;)

i mean, this same preamp was sold for lead, rhythm, bass and keys with slightly different applications.
pretty sure the board are all generic, so some parts/pins/features may or may not even be included, depending on the version
of the circuit.

these guys were as bad as me and fuzzboxes, lol... "hey, lets use the same circuit again and see how many variants we can come up with" lol

the fuzz looks pretty promising. i'm betting adding a gain to it and playing with some values may end up with a decent sounding unit. hell, i intend to improve what is there stock, if possible. ;)

almost ready to check downstairs and see if i'm up for it. it will tell me if it wants me to touch it, i am sure.

damn peyote buttons. things been talking to me that shouldn't be for 40 some years now. lol

^^^^ i may be kidding, or may be not... lol

bad humor i know, can't help it, i was born a mostly white child in the fertile muddy waters of the willimantic river delta...

yeah, the reverb seems to have switches that either send either channel, both, or none to the reverb.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 02, 2019, 11:08:32 PM
Quote
some of the guys at the diy-audio forum think i should start by removing that bridge on the mixer board.
After looking at the biasing I'm pretty sure you either have no mods at all (no added resistors or bridge), or, you have all the added resistors with the bridge.   The resistors + no bridge made the least sense.  The biasing was quite bad.  The DC voltage on the collector (and +rail voltage) will  tell you if it is ok as it is now.

Quote
i will try and trace the socket to where it goes tonite. i think the description coming off the mixer board is in this post:

https://www.diystompboxes.com/smfforum/index.php?topic=121835.msg1147111#msg1147111
Ah excellent - thanks!   I don't know how I missed that.  Maybe back then I couldn't piece it together.

Quote
the trem is the last card before the mixer... circuit flow is channels one and two in parallel, then fuzz, then reverb, then oscillator/tuner and finally trem... then the mixer and outputs.

see the listing of the wires, https://www.diystompboxes.com/smfforum/index.php?topic=121835.msg1147111#msg1147111
the blue wire does go to the fuzz board, pin 10
Ok thanks.  I read over all that stuff again and see if it puts anything into perspective.

The bottom line is it's all pointing to the mixer board!!

Quote
remember, their stuff was pretty vegematic, they'd use exactly the same thing with a bunch of different names for different applications.
I can see why companies do that.  It means all you stuff produce has a consistent sound.  If you come-up with an improvement then you should roll it out on all models.  No point staying with the old.

Quote
the fuzz looks pretty promising. i'm betting adding a gain to it and playing with some values may end up with a decent sounding unit. hell, i intend to improve what is there stock, if possible.
I have a feeling it will be running on a higher supply voltage and might not translate to 9V so well.

Quote
damn peyote buttons. things been talking to me that shouldn't be for 40 some years now. lol

^^^^ i may be kidding, or may be not... lol

bad humor i know, can't help it, i was born a mostly white child in the fertile muddy waters of the willimantic river delta...
:icon_mrgreen:


Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 02, 2019, 11:37:47 PM
yeah, definitely the mixer.
i'm packing a couple guitars up that sold on ebay... yay... we can eat this month ;)
then i'm gonna put it mostly back together so i can fire it up and get some voltages.
may be tomorrow before i get to it, i feel pretty lazy at the moment ;)

i'm betting the fuzz was something else they stole and adapted. if i know dino, he can make it run on 9volts. may have to change some resistor values, but once we know where the shit on the socket goes, and some voltages, we'll be able to figure out a lot more.

personally, i think using the same thing for all their units was either lazyness or productivity, i mean, the bass preamp version also had reverb and fuzz. who the hell uses reverb on bass? ok, chris squire, but...

i figure it was just easier to milk the same designs, i mean, they are gonna work for whatever ya throw into them, so what the hell... one designm many products, right? ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 03, 2019, 12:38:34 AM
Quote
yeah, definitely the mixer.
i'm packing a couple guitars up that sold on ebay... yay... we can eat this month ;)
then i'm gonna put it mostly back together so i can fire it up and get some voltages.
may be tomorrow before i get to it, i feel pretty lazy at the moment ;)

No problem.

Quote
i'm betting the fuzz was something else they stole and adapted. if i know dino, he can make it run on 9volts. may have to change some resistor values, but once we know where the shit on the socket goes, and some voltages, we'll be able to figure out a lot more.
Probably get close.   You lose a bit of gain at low supply voltages.

Quote
i figure it was just easier to milk the same designs, i mean, they are gonna work for whatever ya throw into them, so what the hell... one designm many products, right?
Sure.  Cheaper to make as well.

I've updated the mixer schematic.  I makes sense a lot of sense to me from a how it works perspective.  I'm still not 100% on where pin 7 and 9 end-up.   I got a bit mixed up with the brown wires since there three (dark/light look the same on the pic to me).

(https://i.postimg.cc/9r1Hsgyc/Ovation-K6100-Mixer-Board-V1-1.png) (https://postimg.cc/9r1Hsgyc)

Still don't understand where pin 11 (blue), pin 2 (yellow) and pin 8 (orange) on the fuzz end up. 
No big deal.  The way I've redrawn the mixer certainly puts more emphasis on the fault being in the mixer.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 03, 2019, 01:10:27 AM
Schematic title fix and bias checks


(https://i.postimg.cc/WdcLFDgf/Ovation-K6001-Mixer-Board-V1-2.png) (https://postimg.cc/WdcLFDgf)


(https://i.postimg.cc/2VvgDzMd/Ovation-K6001-mixer-bias-check.png) (https://postimg.cc/2VvgDzMd)
Title: !!!!
Post by: pinkjimiphoton on February 03, 2019, 01:39:59 AM
just got the last of the stuff packed for monday, and pics taken for the next batch of ebay stuff.
tomorrow i'll slap her together and get some voltages. all will be revealed. ;)

yeah, in some cases, they have multiple wires connecting. it makes it even weirder!

what i'll do is start with preamp card one, and trace where the wires go to, and try and work my way thru the whole mess. and get voltages after... better to trace stuff before i re-assemble it.

it LOOKS worse than it probably is cuz its got all the p2p stuff all over... we'll probably end up with enough info some crazy sucker could clone it if they were stupid enough like me wanted to. ;)

i'll also do my best to get the correct values on all the resistors etc on the mixer.

for shits n giggles i may pull the q and try something else with it... i got one of them little chinese tester things, works great for pinouts n gain. if its working, i'll put it back, but if not... that will be our problem, and to me, the most likely candidate as everything else appears to be working. i doubt the resistors or caps have died.

so the 39 and 33k resistors in parallel should be, like, 17.875... call it 18k..  the 22k on the back is in parallel with the 100k, so it works out to 18032.xxx k... so we could call that 18k too, right?

why wouldn't they just use like, a 22k resistor and be done with it? should be close enough i'd imagine.

i definitely wanna compare it with and without that solder blob, too,,, and with one end of both those resistors lifted to see what it does.

right now i'm leaning towards a shorted transistor, thats not actually operating but still passing signal. i had a blown kustom like that years ago i used as a preamp so i could get reverb outta my marshall jcm800 combo,  the power amp was blown, but you could still pass signal thru it.

i'm wondering if them resistors are whats letting the signal bleed thru the whole mess... i bet they fudged it when built, and them resistors are a dodge... or they messed up the design... would seem to me, summing two different preamps together passively would be problematic. maybe the q on the mixer is a gain stage for the mixed channels, or perhaps a buffer to keep the 1 and 2 channels isolated?

i think i picked up a lousy week to give up caffiene... and sugar... and alcohol <<especially alcohol>> and gluten.
that said, i've lost 20 lbs in the last week. so its probably a good thing, but i got the brain fog setting in from no carbs, lol

the damn infection thing isn't helping either. whomever invented this shit should be flogged!!!

left hand ring finger in the first knuckle is where its worst. holy shit. can barely bend it. good thing i'm off til thursday!!
with luck it will be better and i'll dodge a week or two of intravenous antibiotics, cuz man, hospitals scare the piss outta me.
last place ya wanna be if you're sick!!!

anyways, thats it for tonite. thanks for everything rob!!
 8)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 03, 2019, 04:09:54 PM
Quote
what i'll do is start with preamp card one, and trace where the wires go to, and try and work my way thru the whole mess. and get voltages after... better to trace stuff before i re-assemble it.

It's up to you at the end of the day.  These things all always turn out to be more work than you think.   If you can get the connections I could trace the boards.  The channel preamps have 17 connections which involves too much guessing without the wiring.

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it LOOKS worse than it probably is cuz its got all the p2p stuff all over... we'll probably end up with enough info some crazy sucker could clone it if they were stupid enough like me wanted to.
Funny you should say that.  I was thinking both of those things the other day.

Quote
for shits n giggles i may pull the q and try something else with it...
Should be fine.   The only thing you might need to be careful about is the transistor voltage.  I don't know what the supply rail is on that thing.  Some transistors might poop out.

Quote
so the 39 and 33k resistors in parallel should be, like, 17.875... call it 18k..  the 22k on the back is in parallel with the 100k, so it works out to 18032.xxx k... so we could call that 18k too, right?

why wouldn't they just use like, a 22k resistor and be done with it? should be close enough i'd imagine.

That's why I think it's a factory mod.   They built the boards and the gain was probably too low so they tweaked the design and instead of pulling parts they just solder extra parts one.    To me this makes sense because the part values before and after the mods seem to show correct bias points.
(The mods also drop the the output impedance.)

Quote
think i picked up a lousy week to give up caffiene... and sugar... and alcohol <<especially alcohol>> and gluten.

Maybe too much to slam on yourself all at once.   Dumping caffeine alone can screw you up for a week or more.

Quote
that said, i've lost 20 lbs in the last week. so its probably a good thing, but i got the brain fog setting in from no carbs, lol

20lbs is one week is crazy.   The "safe" weight loss rate is something like 1kg/wk (2lbs/wk). 

Quote
the damn infection thing isn't helping either. whomever invented this shit should be flogged!!!
I freakin hate getting sick or anything like that.    Good luck with it.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 03, 2019, 07:06:50 PM
well, since the super bowl is on and i have a superior bol i'm far more interested in, when i get done typig this, gonna start the herculean task of writing connections down. its not as bad as it seems, cuz of the modularity.

btw, the blue wire on the fuzz board goes to the input of the channel 2 volume pot, which is stacked.

the fuzz switch just shorts to ground. i won't try to remember which colors are which yet, wanna write all that crap down while i'm looking at it.

so i'm guessing the batch of transistors they got was too low a beta for the job, so they tried to bias it.

once we get the voltages and connections, i'm imagining pretty much any q will make it fire.  but still, its the most likely thing to go wrong with the dang board! its the only semi on there!

we'll see. if i'm up to it i'll go for voltages tonite too. it only takes a few minutes to reassemble the sucker. they got THAT part right at least.

betcha they said screw it, it passes signal.... friday job ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 03, 2019, 07:28:09 PM
Quote
onna start the herculean task of writing connections down. its not as bad as it seems, cuz of the modularity.
After all the poking around you will know the lie of land.

Quote
btw, the blue wire on the fuzz board goes to the input of the channel 2 volume pot, which is stacked.
OK so it's pretty hard bolted into channel 2.

Quote
the fuzz switch just shorts to ground. i won't try to remember which colors are which yet, wanna write all that crap down while i'm looking at it.
Yep,  I capture that in last Fuzz pic, but not the colors.

Quote
so i'm guessing the batch of transistors they got was too low a beta for the job, so they tried to bias it.

once we get the voltages and connections, i'm imagining pretty much any q will make it fire.  but still, its the most likely thing to go wrong with the dang board! its the only semi on there!

we'll see. if i'm up to it i'll go for voltages tonite too. it only takes a few minutes to reassemble the sucker. they got THAT part right at least.

betcha they said screw it, it passes signal.... friday job
Yes, might have got under the radar from something like that.  The transistor could have been flakey from day 1.

One thing I find funny is the whole motivation behind the product was to have this robust fault-tolerant design, but the mixer, which connects to the evil outside world was excluded and didn't get any extra protection.   It's like those half-baked government policies.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 03, 2019, 07:31:31 PM
most especially that last line.

yeah, why make it bullerproof and give it a huge achilles heel?

gonna grab some grub and down i go
there i go, there i go

there
i
go

lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 03, 2019, 10:29:55 PM
I just noticed something.   The last stage of the Fuzz is very much like the unmodified mixer (ie. no parallel R's and no bridge).    The emitter resistor value might be different.    I can't quite see the value clearly on the mixer pics.   It doesn't look the same value as the Fuzz.   IIRC it didn't make a big impact on the biasing (because the 33k goes across b and e instead of the usual b and ground).
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 04, 2019, 12:56:37 AM
robbro ;)
i didn't trace EVERYThing...

but i DID get a LOT of notes, including what from what socket connects to what for all the boards.
also got voltages for the mixer and the fuzz.

looks like most of the fuzz board isn't even used. we may be able to fix that. ;)

the mixer stage voltages are weird as hell
the b+ is about 22 volts, it was swinging between about 21- 22.. at the power  supply appears to start as 25vdc

anyways, the transistor in the mixer reads like this

C   10.75
b      .56
e       0

seems to me, the voltage at b should be higher, c, too, probably. i wonder if they fudged it with a lower voltage q than they should have used. this was mos def def def a friday afternoon job... like, 4:30, and its the 60's, and you have run out of reasons to run to the bathroom every 15 minutes, and gotta get up and went so who cares if a pos gets thru?

lol.. i am i think gonna scan stuff. its probably easier than trying to type it all.
that way, drawings, notes etc are there.

i am not sure on the power supply yet, i have to give it a hard look. it uses some kind of terminal blocks i've never seen before to distribute power everywhere, and there's one on both sides of where the power filter caps are.

also, i blew up the circuit breaker, ooops. meter probe slipped. took me about 10 minutes to figure out wtf was wrong. jumpered it . back to life, pretty much the same as it was.
i'm thinking i wanna remove that solder bridge tomorrow and see if that b voltage comes up, i'm betting it does.

btw... no fuses in the damn thing, just the circuit breaker i broke breaking stuff.

its gonna be messy. i will try to translate as best i can, and forgive my febrile scrawl, never was much of a penmanship dude. chicken scratch may be more legible.

i think you'll be able to finger it out.
be back shortly with a mess-o-scans
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 04, 2019, 01:19:31 AM
Quote
i didn't trace EVERYThing...

but i DID get a LOT of notes, including what from what socket connects to what for all the boards.
also got voltages for the mixer and the fuzz.
No problem.   Whatever you can do is OK with me.

Quote
looks like most of the fuzz board isn't even used. we may be able to fix that.
Is the board going to grow to the size of the enclosure  :icon_mrgreen:

Quote
the mixer stage voltages are weird as hell
the b+ is about 22 volts, it was swinging between about 21- 22.. at the power  supply appears to start as 25vdc

anyways, the transistor in the mixer reads like this

C   10.75
b      .56
e       0

seems to me, the voltage at b should be higher, c, too, probably. i wonder if they fudged it with a lower voltage q than they should have used. this was mos def def def a friday afternoon job... like, 4:30, and its the 60's, and you have run out of reasons to run to the bathroom every 15 minutes, and gotta get up and went so who cares if a pos gets thru?

Somehow I screw up my bias circuit before.   I was wait until we pin down the voltages before I fixed it.

To me the base looks OK-ish.   If it's a larger transistor running at lot current that's fine.  Like if it was 600mV at 1mA collector current it would be perfectly normal to get 0.54V at 100uA collector current.

With the mixer part values as is I get Vc= 14.2V for the 2N3904 and 11.1V for the 2N2222.   Your voltage isn't too far off the 2N2222 so maybe OK.    So what the hell's going on with that thing!   

[BTW, with the mods taken out I get 9.7V for the 2N3904 and 8.6V for the 2N2222.    That's with an emitter resistor of 22k, which don't know is correct yet.]

When you measured the mixer voltage did you measure the solder part of the pins or the actual parts on the pcb?   It crossed my mind maybe the edge-connector could have bad connections.   That would cause also sort of weird behaviour.

Quote
also, i blew up the circuit breaker, ooops. meter probe slipped. took me about 10 minutes to figure out wtf was wrong. jumpered it . back to life, pretty much the same as it was.
Ouch.

Quote
its gonna be messy. i will try to translate as best i can, and forgive my febrile scrawl, never was much of a penmanship dude. chicken scratch may be more legible.

think you'll be able to finger it out.
be back shortly with a mess-o-scans
My writing is pretty bad too.  When I was in overseas people in the hotel asked me what language is that  ;D.   A friend of mine is even worse.

Whenever you get time.

Do you have an oscillator or and/or an oscilloscope?     I wonder if we can measure the gain of the mixer stage.   Not sure what to think after your mixer measurements.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 04, 2019, 01:38:23 AM
sadly i done run outta jam for the nite.
i will scan all the stuff tomorrow. i measured voltage at every pin of every socket on all the boards.
also wrote what connects to where. its gonna be confusing but about 80% of the circuit is actually traced other than a couple of wires to the trem switches and the power supply.

there's 8 pages of connections i wrote out.
i wrote which number of each socket, what wire goes where, what color for every one of 'em
both channels
the fuzz, reverb, tuner, trem and mixer board.

it REALLY seems like that mixer board needs more freekin gain. it can't compete with the channel 2 only output.  and it appears to be just what it is... a buffer stage, right? or a gain stage? what ever, it needs more ... ummm... "intestinal fortitude " for sure. lol

anyways... more tomorrow bro. thanks for takin the cruise with me. ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 04, 2019, 01:49:42 AM
I just did some playing around on the simulator.

I also did some pondering.   One thing which can affect the gain of the mixer is the reverb board.
So maybe you should check the gain with the reverb board out.

Assuming the output impedance of channel 1 or channel 2 looks like about 100k  (a total guess) the gain of the mixer as a whole *without the reverb board* is about unity.   Within +1dB and -2dB  depending on the transistor.

With reverb in the gain drops about 1dB

With the resistor mods removed and the solder bridge removed the gain is really low.  -14dB with the all the mods in and -25dB with the mods out.

So it seems the mods are required to ensure the overall gain of the mixer is unity.

That also means the BOTH jack and the CH2 Only jacks should produce about the same level.  However we know they don't.

So I was thinking maybe the reverb board is stuffed?  That could load down the input to the mixer (via the purple wire on pin 1) 

Can you do a level test with the Reverb board pulled?
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 04, 2019, 01:50:44 AM
Quote
sadly i done run outta jam for the nite.
You can only do what you can.  No hurry.

I posted another post just a second ago.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 04, 2019, 11:42:41 AM
I just did some playing around on the simulator.

I also did some pondering.   One thing which can affect the gain of the mixer is the reverb board.
So maybe you should check the gain with the reverb board out.

Assuming the output impedance of channel 1 or channel 2 looks like about 100k  (a total guess) the gain of the mixer as a whole *without the reverb board* is about unity.   Within +1dB and -2dB  depending on the transistor.

With reverb in the gain drops about 1dB

With the resistor mods removed and the solder bridge removed the gain is really low.  -14dB with the all the mods in and -25dB with the mods out.

So it seems the mods are required to ensure the overall gain of the mixer is unity.

That also means the BOTH jack and the CH2 Only jacks should produce about the same level.  However we know they don't.

So I was thinking maybe the reverb board is stuffed?  That could load down the input to the mixer (via the purple wire on pin 1) 

Can you do a level test with the Reverb board pulled?

no output change with the reverb board pulled. that was one of the first things i tried.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 04, 2019, 01:58:34 PM
ok, as promised, the results of last nite's tracing of the sockets, etc

chan 1 socket, 18 pins
(https://i.postimg.cc/qzPfmpCC/chan-1-socket.png) (https://postimg.cc/qzPfmpCC)

chan 2 socket, 18 pins

(https://i.postimg.cc/r0F7dm77/chan-2-socket.png) (https://postimg.cc/r0F7dm77)

fuzz socket, 12 pins

(https://i.postimg.cc/WDsHKzpt/fuzz-board-socket.png) (https://postimg.cc/WDsHKzpt)

mixer connections... did i mention its the only one of the "switches" designed to come off?yeah... fudgepackers!! lol

(https://i.postimg.cc/6yGg4F16/mixer-connections.png) (https://postimg.cc/6yGg4F16)

pot and rocker switch values, volume pots are dual stacked, fuzz pot has on/off switch at "zero"

(https://i.postimg.cc/gxV7N8Wf/pots-n-rockers.png) (https://postimg.cc/gxV7N8Wf)

reverb socket

(https://i.postimg.cc/qgq94Ns3/reverb-board-socket.png) (https://postimg.cc/qgq94Ns3)


trem board socket
(https://i.postimg.cc/7J5cVRHV/trem-board-socket.png) (https://postimg.cc/7J5cVRHV)

tuner socket

(https://i.postimg.cc/4YkM6wr6/tunerboard-socket.png) (https://postimg.cc/4YkM6wr6)

voltage readings

(https://i.postimg.cc/r0n35Tks/voltages.png) (https://postimg.cc/r0n35Tks)

hopefully will answer a couple questions, and make it easier for the theoretical future man to build one lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 04, 2019, 04:17:09 PM
Quote
no output change with the reverb board pulled. that was one of the first things i tried.
Even more puzzling.  BTW, I actually screwed up on the level drop with the reverb board in; I must be getting tired too  :D.

The problem must be somewhere in the mixer.    I just can't see what the problem is.    What about the input or output caps?  Normally I wouldn't expect problems with those.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 04, 2019, 04:18:51 PM
Quote
ok, as promised, the results of last nite's tracing of the sockets, etc
Wow! dude!  that's a lot of stuff to get down.   Might take a while for me to process it all.
Infinitely better than poking around for clues on the random gut shots.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 04, 2019, 10:27:43 PM
HAHAHAHAH sorry to inundate you bro!! ;)
but yeah, definitely in the mixer, and a shitty design.
since the b+ is only 25 v, should be able to find a replacement for the tranny if need be,
it COULD be the caps, but seems unlikely.
i think they were just too high on coke or did too many shrooms when they designed it.
i'm gonna try and undo the blob and mods and see if the volume comes up. if it does, cool, if not, i guess next step is continuity point to point, and then replacing each component on the mixer board.
i may hack an lpb1 or something similar into it to get the gain up on the summed outputs.
but i suspect the volume discrepancy is from the design... i mean, no reverb on channel two by itself, the switch is what connects the bloody reverb on the channel 2 only output.

i think they didn't think this thru all the way. we'll see!
let me know if there's any other info needed, and i will do my best to get it done.

gotta go spend some breadboard time... i recently gotta gig designing fuzzboxes for a company in georgia! diggin it!
one of the few things i seem to be any good at lol
talk soon brother... peace!

yeah, took me from 8:00 pm last nite til 1:30 or so am to get all that shit traced. as ya can see, i had a few false positives i had to ammend, too... some of it was kinda tricky to see!

i went with numbering for the sockets left to right, but the keyways in each board will tell ya if i got the alignment correct, sorry, i may have got some stuff mirrored inadvertantly.
i wanted to do it with the boards in place, but it was impossible to see everything.
i believe what i posted earlier is deadnuts right.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 04, 2019, 11:34:13 PM
Quote
HAHAHAHAH sorry to inundate you bro!!
Yeah, I can't keep up now.  I looked over the preamp this morning.   All the connections makes my head hurt a bit but at the end of the day it's kind of a James tone control ("Passive Baxandall").   And yep the tremolo modulates the gain of one of the stages - a bit like the EA Tremolo but with a vactrol instead of a JFET.

Quote
i'm gonna try and undo the blob and mods and see if the volume comes up. if it does, cool, if not, i guess next step is continuity point to point, and then replacing each component on the mixer board.
Maybe just try it.  The more I look at it the less I think that will fix it.

The weird thing is "Channel 2 Only" output is at the right level.   Also when I simulated the mixer it should pretty much give a gain of 1 from either channel to the "Both Output".   So that means *channel 2* at least should come through at the same level as "Channel 2 Only".     Pulling the reverb and tremollo don't affect or fix the problem so it's not those.   It really need a signal generator up it's clacker and an Oscilloscope to find where the signal is being lost.

One question:  When you use the "Both Outputs" is Channel 1 and Channel 2 more or less the same level?  When listen to channel 1 make sure channel 2 is turned right down, and when listening to channel 2 make sure channel 1 is turned right down.

Quote
i think they didn't think this thru all the way. we'll see!
Maybe not.   I need to piece that stuff you posted together.

One thing I keep thinking is the mixer inverts the signal.   In Separate Mode channel 2 goes straight out the "Channel 2 only" connector.   However Channel 1 goes through the mixer which inverts channel 1.  So does that mean Channel 1 and Channel 2 cancel each other in Separate Mode.   if they don't then does that mean Channel 1 and Channel 2 cancel each other in "Parallel Mode"?

There's something whacked with this set-up.

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yeah, took me from 8:00 pm last nite til 1:30 or so am to get all that shit traced. as ya can see, i had a few false positives i had to ammend, too... some of it was kinda tricky to see!
Sometimes that stuff sends your head spinning.   The later it gets the blurrier you eyes and fuzzier your mind and you keep having to back track over stuff because you make mistakes.

Quote
went with numbering for the sockets left to right, but the keyways in each board will tell ya if i got the alignment correct, sorry, i may have got some stuff mirrored inadvertantly.
Yes.  I noticed that.  No big deal I don't know if we should just flip the numbering now instead of carrying it through to the schematics.    Not a big deal provide we make a note of it.






Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 05, 2019, 01:01:45 AM
dude... i got it. ITS ALIVE

and WICKED loud. the reverb is studio quality and pretty much to die for.
the fuzz on its own is horrid, BUT

if you were say to use, like a fuzzface, or an octavia, or a super hot rodded big muff pi with a three band active eq grafted in where the tone stack used to be, its absolutely killer.

like.. imagine an extra gain stage of treble boosted fuzz. its sickening, its stomach turning, i gotta send the schematic to dave at lucifer's trip to add to the collection, he'll love it.
holy shit. makes it just cut right thru everything, real nice sustain, total sizzle
and with the reverb even better.
i got my princeton volume OFF and the preamps up a fair amount, and its loud enough for my girlfriend too bitch lol.. always a good sign.
so i'm gonna kinda HAVE to trace the rest of it out, for posterity, i think, including the values n stuff where i can get them. its actually just as cool as i remember.
now that i think of it, what i loved so much about it was the way it worked with my UMI buzztone and expander, really brought the guitar to life with some sizzle into a vox solid state combo... a 2 x 12 verticle bass combo that sat in this cool little baby perambulator lookin contraption. it had no reverb, no balls really. but man, with this thing and that buzztone crankin
#FuzzyGoodness

sick.

so i disconnected the bottom bias resistor at ground. definitely a factory thing, i think they f'd up the circuit board there, no trace from e to ground. what they did was solder the southern end of the resistor first to e, then jumpered the whole thing to the adjacent ground trace.
disconnecting it had a very minor effect on the circuit, it just got noisier and a bit gainier...
i put it back together seeing no particular improvement.
i also took voltages, c 10.1, b .5, e 0. same as last nite.

so jack darr comes in, and saves the day yet again from the shades.

circuit disturbance test. time to whack the bejesus outta each component and see what happens.

whacked it with a probe. just IT. the board.
ROAAAAAAAAAAAR goes my amp.
hmm.
curious.

so i whacked the first big cap closest to me, it roars again, but obviously ain't the problem

so i wacked the second big cap, the .47u output... KERANNNNNGGGGG goes my amp. soon as i take the meter off, dead.

turned it off, let it discharge, reflowed the cap with some fresh old school possibly illegal solder
and popped it on.

i had sound.. equal between the two preamps.
preamp ONE is louder than two slightly. the slot is.
turns out, preamp board one was actually preamp board TWO.
a little bassier, drives the fuzz better. so i swapped them.

now channel one is a little louder when both channels are used,
channel two has fuzz, none on channel one <unless ya jumper the channels, which ya KNOW i did> (')
reverb works on both channels, as does top boosts, and tremolos
channel two output and paralleled output now equal in volume
it was the damn output cap... of course ;)
must've took a good hit in transit.
channel two only has fuzz but no reverb. as its supposed to be in the catalog.
i'll try and get some video of the beast.

i think they figured every self-respecting professional guitarist would have a fuzzbox already they played thru at the time.. so they made theres a fuzz helper, footswitchable for a lead boost that really actually WORKS.
i'm re-impressed.

so, ya got your tonebenderface on, ya turn your guitar up n down, and kick this on when ya need to burn. pretty cool for 1969 tech!

the tone shaping possibilities are hip. i can't wait to put my studio back up and do some old school analog recordings... ummm,. digitally, like i used to do.

this thing and the ludwig and an echoplex and a few choice fuzzes could be a ticket to nelvana-ish bellybutton window gazing. its hip. its now. its 50 @#$%ing years ago. wtf lol

so... should we go all the way for it, or what?

btw, the strobe tuner thing actually works freeking great and is a trip to play with.
cranked up its an in tune G, third fret of the high e string.
you can tune it downward to almost any other note. if ya tune it to where e is, you can downtune it with the knob and do the sounds before "jet airliner" by steve miller. just add highly regenerative echoplex and maybe a moog on the side ;)

let me know how far ya dare go. i'm willing to gather data, but it may be a major pain in the ass.

i am toying with the idea of maybe changing them little caps in the fuzz circuit to give it more ass

i bet going from 1n to 100n will be a substantial improvement in the fuzz tone, but it may ruin the function described earlier i am pretty sure it was designed to do.


maybe a switch somewhere  :icon_twisted: :icon_twisted: :icon_twisted:

i'm gonna have to disassemble the entire switching rack to put the mixer and reverb switches back on, we've already got most of it, so all thats left really is a couple of the wires on the switches, and the power supply.

shoot, we don't even really NEED the power supply. most of the boards run at either 10 volts... could run 'em at 9 and i doubt they'd blink.... or 21.... run 'em at 17v with a charge pump, or step it up to one of them 24v transformers and regulate it down to 21 and 10 volts.
a modern power supply would probably actually be an improvement to the original design, you can put the transformer farther away from the unit.
i'm surprised how quiet the unit actually is, considering.

i dunno. madness. MADNESS, i tell you...
but this thing is actually kinda freekin hip!!!

gonna have to figure out the wiring for the footswitch, i know its a 6 pin din and the footswitch had three buttons, fuzz, reverb, and tremolo. should be fairly easy to do ;)

man. thanks so much for all the help, dude. you freekin rock, rob!

anyways... let me know whatcha wanna do, and if there's info needed i am missing.
i can get resistor values, caps, etc etc and better detail on things.
just lemme know ;)

peace out







(') the crux of the biscuit is the apostrophe..... ps... forgot... jumper channel one to channel two? not only puts the channels in parallel, but you can use channel one to overdrive @#$%ing channel two. sick. SICK!!!!!!!!!!!!!!!!!!!!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 05, 2019, 01:30:20 AM
Quote
dude... i got it. ITS ALIVE

and WICKED loud. the reverb is studio quality and pretty much to die for.
the fuzz on its own is horrid, BUT
Freak awesome!

Quote
its loud enough for my girlfriend too bitch lol.. always a good sign.
Indeed  :icon_mrgreen:

Quote
so jack darr comes in, and saves the day yet again from the shades.

circuit disturbance test. time to whack the bejesus outta each component and see what happens.

whacked it with a probe. just IT. the board.
ROAAAAAAAAAAAR goes my amp.
Excellent - when all else fails kick it!

Quote
so i wacked the second big cap, the .47u output... KERANNNNNGGGGG goes my amp. soon as i take the meter off, dead.
... I can smell the blood ...

Quote
it was the damn output cap... of course ;)
must've took a good hit in transit.
It always turns out to be the last thing on the list for shitty problems like this.

Quote
now channel one is a little louder when both channels are used,
channel two has fuzz, none on channel one
There's something in the manual about ch1 being louder than ch2 in one of the modes.
That's a good sign, means it really *is* working like a bought one.

Quote
so, ya got your tonebenderface on, ya turn your guitar up n down, and kick this on when ya need to burn. pretty cool for 1969 tech!

the tone shaping possibilities are hip. i can't wait to put my studio back up and do some old school analog recordings... ummm,. digitally, like i used to do.

this thing and the ludwig and an echoplex and a few choice fuzzes could be a ticket to nelvana-ish bellybutton window gazing. its hip. its now. its 50 @#$%ing years ago. wtf lol

Finally some fun after all the screwing around.

"nelvana-ish bellybutton window gazing"  :icon_mrgreen: where did that come from.

Quote
btw, the strobe tuner thing actually works freeking great and is a trip to play with.
Cool.

Quote
i bet going from 1n to 100n will be a substantial improvement in the fuzz tone, but it may ruin the function described earlier i am pretty sure it was designed to do.

maybe a switch somewhere  :icon_twisted: :icon_twisted: :icon_twisted:
I had a feeling you were going to mod it.  Especially those caps.

Quote
i'm gonna have to disassemble the entire switching rack to put the mixer and reverb switches back on, we've already got most of it, so all thats left really is a couple of the wires on the switches, and the power supply.
If you want to clean-up a few things that's find.
BTW, what reverb tank does it use?    The circuit looks like it can only handle a very high impedance drive coil.
Quote
i dunno. madness. MADNESS, i tell you...
but this thing is actually kinda freekin hip!!!

gonna have to figure out the wiring for the footswitch, i know its a 6 pin din and the footswitch had three buttons, fuzz, reverb, and tremolo. should be fairly easy to do ;)

man. thanks so much for all the help, dude. you freekin rock, rob!
No problem at all.  I'm really happy it finally got up and sang.

Quote
anyways... let me know whatcha wanna do, and if there's info needed i am missing.
i can get resistor values, caps, etc etc and better detail on things.
just lemme know
Well today I poked around with the preamps.  Sooo many connections.   Your reverse mixer numbering really messed with my brain - many translations going.   I'll have to flip a few numbers so it matches the schematic.

I'm pretty sure I will have some questions.  Like there's a few parts off the PCB which are point to point tack onto things.

Good stuff!!!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 05, 2019, 01:04:24 PM
Quote
dude... i got it. ITS ALIVE

and WICKED loud. the reverb is studio quality and pretty much to die for.
the fuzz on its own is horrid, BUT
Freak awesome!


yeah boyeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee!

Quote
its loud enough for my girlfriend too bitch lol.. always a good sign.
Indeed  :icon_mrgreen:

Quote
so jack darr comes in, and saves the day yet again from the shades.

circuit disturbance test. time to whack the bejesus outta each component and see what happens.

whacked it with a probe. just IT. the board.
ROAAAAAAAAAAAR goes my amp.
Excellent - when all else fails kick it!

Quote
so i wacked the second big cap, the .47u output... KERANNNNNGGGGG goes my amp. soon as i take the meter off, dead.
... I can smell the blood ...

Quote
it was the damn output cap... of course ;)
must've took a good hit in transit.
It always turns out to be the last thing on the list for shitty problems like this.[/quote]

yep, as usual, the very last @#$%ing component literally in line!! haha... but its good to know i iso'd it to that board... my powers grow!!! lol



Quote
now channel one is a little louder when both channels are used,
channel two has fuzz, none on channel one
There's something in the manual about ch1 being louder than ch2 in one of the modes.
That's a good sign, means it really *is* working like a bought one.[/quote]

yeah, i gotta get another circuit breaker, and i think i'll replace the filter caps, as its a bit noisy.  but maybe leaving it on for a couple days will help, a lot of times that will "dry out"
 the moisture the cc resistors tend to absorb, and make the bacon frying and hiss go away.



Quote
so, ya got your tonebenderface on, ya turn your guitar up n down, and kick this on when ya need to burn. pretty cool for 1969 tech!

the tone shaping possibilities are hip. i can't wait to put my studio back up and do some old school analog recordings... ummm,. digitally, like i used to do.

this thing and the ludwig and an echoplex and a few choice fuzzes could be a ticket to nelvana-ish bellybutton window gazing. its hip. its now. its 50 @#$%ing years ago. wtf lol

Finally some fun after all the screwing around. [/quote]

oh hell yeah... this thing feeding my echoplex outta channel two into the wet channel of my pro reverb, and the dry channel getting the main out with reverb? be still my heart!!
i am a huge fan of multiple reverbs being on. live, i tend to run one on my board, one on top of my amp as a line driver/buffer with more reverb, and the one on my amp cranked up a fair amount. reverb narcossis? naaah... but really complex reverbs and tone? oh hells yes!

Quote
"nelvana-ish bellybutton window gazing"  :icon_mrgreen: where did that come from.

remember all that peyote and lsd i mentioned? well, all these years later, still "on the bus" ;)

belly button window comes from hendrix, belly button contemplation comes from mad magazine back in the 60's raggin
on hippies, nelvana came from the old holistic harry cartoons in playboy in the late 70's and early 80's... somehow the whole mess sloshed around the abcess twixt my ears til it came out like that.

sorry? lol



Quote
btw, the strobe tuner thing actually works freeking great and is a trip to play with.
Cool.

Quote
i bet going from 1n to 100n will be a substantial improvement in the fuzz tone, but it may ruin the function described earlier i am pretty sure it was designed to do.

maybe a switch somewhere  :icon_twisted: :icon_twisted: :icon_twisted:
I had a feeling you were going to mod it.  Especially those caps.[/quote]

i AM thinking about it, but i kinda like the fuzztone as it is, as a footswitchable extra stage of madness.
i have tonnes of great fuzzes, so i think i'll leave it as is... tho i may try it modded to see how it sounds.
i still wanna resurrect it to a standalone any way we end up going!!
Quote

Quote
i'm gonna have to disassemble the entire switching rack to put the mixer and reverb switches back on, we've already got most of it, so all thats left really is a couple of the wires on the switches, and the power supply.
If you want to clean-up a few things that's find.
BTW, what reverb tank does it use?    The circuit looks like it can only handle a very high impedance drive coil.

good question, i will look for numbers on it, or try and measure it. looks like a typical accutronics tank, similar too what i see in kustoms n stuff from that era.

Quote
i dunno. madness. MADNESS, i tell you...
but this thing is actually kinda freekin hip!!!

gonna have to figure out the wiring for the footswitch, i know its a 6 pin din and the footswitch had three buttons, fuzz, reverb, and tremolo. should be fairly easy to do ;)

man. thanks so much for all the help, dude. you freekin rock, rob!
Quote
No problem at all.  I'm really happy it finally got up and sang.

i think once its gone thru and cleaned up with some fresh can caps etc it wil really scream!


Quote
anyways... let me know whatcha wanna do, and if there's info needed i am missing.
i can get resistor values, caps, etc etc and better detail on things.
just lemme know
Quote
Well today I poked around with the preamps.  Sooo many connections.   Your reverse mixer numbering really messed with my brain - many translations going.   I'll have to flip a few numbers so it matches the schematic.

sorry, my bad. i made a conscious decision to locate pins via the keyway, its the only way i could write all the connections down and not go batshit crazy myself. soooooo many connections!!! the boards orient in different ways, so its hard to say pin 1 is pin 1, like, in the case of the fuzz and reverb board, pin one of the fuzz with the back of the board facing you would be pin 12 of the reverb. so i apologize!!

Quote

I'm pretty sure I will have some questions.  Like there's a few parts off the PCB which are point to point tack onto things.

Good stuff!!!

just let me know, i will get all the info possible!

i'm betting the whole mess could be made to run off a 9volt power supply and a charge pump! ;)

again, thanks!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 05, 2019, 04:45:05 PM
Quote
yeah, i gotta get another circuit breaker, and i think i'll replace the filter caps, as its a bit noisy.  but maybe leaving it on for a couple days will help, a lot of times that will "dry out"
 the moisture the cc resistors tend to absorb, and make the bacon frying and hiss go away.
I guess that's the problem with old stuff now.    The caps are really on the edge of the cliff.   Those cc resistors drive me crazy.   I know it's anti-mojo but when you have resistor values drifting and things getting noisy it's a real pain.


Quote
oh hell yeah... this thing feeding my echoplex outta channel two into the wet channel of my pro reverb, and the dry channel getting the main out with reverb? be still my heart!!
i am a huge fan of multiple reverbs being on. live, i tend to run one on my board, one on top of my amp as a line driver/buffer with more reverb, and the one on my amp cranked up a fair amount. reverb narcossis? naaah... but really complex reverbs and tone? oh hells yes!

Believe it or not, I've never tried that. 

Quote
belly button window comes from hendrix, belly button contemplation comes from mad magazine back in the 60's raggin
on hippies, nelvana came from the old holistic harry cartoons in playboy in the late 70's and early 80's... somehow the whole mess sloshed around the abcess twixt my ears til it came out like that.
That's a complex recipe.   I do remember the Mad magazines, perhaps more from the late 70's.

Quote
sorry, my bad. i made a conscious decision to locate pins via the keyway, its the only way i could write all the connections down and not go batshit crazy myself. soooooo many connections!!! the boards orient in different ways, so its hard to say pin 1 is pin 1, like, in the case of the fuzz and reverb board, pin one of the fuzz with the back of the board facing you would be pin 12 of the reverb. so i apologize!!
It's OK.  I tried to eyeball it and keep the number in my head but it only takes a bit of tiredness and I start losing the plot. 

The mixer is a bit weird it has eyelets but it also has a few solder tags.   I included the solder tags in the numbering.

One question,  on you wire list for the mixer, does pin 4 go to channel 1 volume (not channel 2)?

Quote
my bad. i made a conscious decision to locate pins via the keyway,
I'll try to stick to that on my schematics and renumber the lists if required.

Quote
i'm betting the whole mess could be made to run off a 9volt power supply and a charge pump!
Probably.  There's actually quite a few parts on the channel boards but not too bad.  If you dump the reverb, mixer, tremolo, and tuner  it would be vastly simplified.





Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 05, 2019, 06:41:45 PM
i will check the wire to be sure when i go downstairs in a few, but pretty sure channel 2 only. i will confirm, also gonna write out the connections for the vegematic switches so i can reassemble her and button her up.
todays the first day i feel ok, if tired, i may run out of steam, so....

 ;)

but its alive!!!! lol

i think it would make a great little standalone project. but.. the trem is kinda weak, the REVERB is incredible tho.

the caps are indeed old. i gotta haynes jazz king from 1959 thats easily 10 years older, and the filters are STILL ok in it, cuz they over-rated them so much. the haynes has a circuit breaker, too.

this thing's main cap is 10,000uf at 150, so... i wanna verify that voltage tho, i imagine its more like 200 or 250. overrated like that seem to survive better in my limited experience so far. i dunno if they develop their full potential like that, but, hey, if they work....

still, gonna probably replace just for safety's sake. if ya really crank up the amp, this thing is loud hissy and obnoxious ;)

kinda like me ;)

i never use CC anymore. i replace everything with metal film and be done with it. cc mojo is largely bullshit. they're spitty, crackly, hissy, muddy devices. @#$% 'em. lol

most of the caps in the circuit itself are all poly or orangedrops or similar. power supply is three can caps and two big diodes, with a transformer to step down the line voltage to about 28 volts i'm imagining. been a long time since i messed with amps so i forget how the formulas work for it, but the b+ works out to about 22 volts in the end.

i am a HUGE fan of multiple reverbs. for extra added points, throw an echo in the mix too, and you can recreate a lot of environments. of course driving a fender or marshall or whatever into distortion WITH REVERB is a completely different animal than reverberation post distortion! try it. i think you may like it.

much smokier sounding to my ears, and not as much diffusion it seems like... the guitar sound still cuts thru.

dick dale can't be wrong ;)

i started reading mad when i was about 4, stolen from my brother. no wonder i'm all messed up. ;)

yeah, the mixer i have a feeling was used in more than one product, from the way it appears to be wired... like, multiple wires soldered to one point, or wire stripped "in the middle", soldered to it, then run to other points.

somebody somewhere is gonna be glad we did all this someday.

watch... i'll make a freekin video extolling its virtues, and suddenly they'll pop out of the woodwork like %^&*roaches lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 05, 2019, 11:18:40 PM
Today progress is slow from my side as well.  Can't seem to get things to match-up.  Maybe I'll post what I have and you can kick the wheels back into shape.

Quote
i think it would make a great little standalone project. but.. the trem is kinda weak, the REVERB is incredible tho.
I suspect the tremolo could be fixed there's some resistors in series with the Vactrols which are going to limit tremolofication  :o.    Reverb is a very simple ckt.  Has a low-pass filter.  Looks like in between voltage and current drive, ie. voltage drive through a resistors.

Quote
i started reading mad when i was about 4, stolen from my brother. no wonder i'm all messed up.

(http://blog.imagesmith.com/wp-content/uploads/2014/05/MADcover.jpg)

(http://4.bp.blogspot.com/_-H-t-Wz1VNU/TLFzmkP2v0I/AAAAAAAAMI4/7YJYcowOL0k/s1600/Mingo_Mad_1968-04_100.jpg)

Quote
somebody somewhere is gonna be glad we did all this someday.
I'm sure of it.  Doesn't matter how obscure something is some poor bugger will get stuck on an obscure beastie.

Quote
watch... i'll make a freekin video extolling its virtues, and suddenly they'll pop out of the woodwork like %^&*roaches lol
Be good to hear it.     Roaches - lol!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 06, 2019, 12:16:15 AM
unh hunh huh huh... hey, beavis, he said....

lmao. love it. what me worry?

so i didn't do anything i set out to do. i messed with some fuzzboxes with it, dialing in various things, running both channels paralleled with a jumper like we used to do on marshalls before all the modern amenities got added all the 13 year olds with daddy's credit cards needed <g>.... holy cow. interesting. the #2 input on each channel is slightly different gain and voice it seems like from the # 1 inputs, but ONLY when jumpering channels. so like, plug in channel one, input 2, and run a jumper from channel 1 input 1 to channel 2 input 1 or 2, 2 will be slightly hotter.
the interaction of the two channels is really strange too, particularly after i
molested the fuzz slightly like we all knew i was gonna do.
just for shits n grins i tacked 3 .1u caps shunting across the .001u caps, which i guess is .101u there instead.
NOW the fuzz actually sounds fairly good, and if ya jumper the channels right you can get a real nice brownish overdrive out of it.
the fuZz is in parallel, so theres always an element of clean to it sorta. it does a REAL good mimic of a warm old tube amp, and i was playing it with no other effects and getting real close to the same tones i normally would use live.

so i think the fuzz will be a keeper. but i think the preamp card, or part of it, is part of the fuzz circuit. how you drive the preamp determines how hard the fuzz drives, too. the higher the preamp volume, the hotter the fuzz seems to get. the tone controls have a little to do with it too, but not much. of course, this is AFTER changing the cap values to let some bass in.
still works good with a ge fuzzface into the front end.
sounds a lot like a brown or early blackface fender when ya dial it in right.

yeah, if we can un-neuter the tremolo and give it slightly bigger bollocks that could be fun, too. its pretty faint as is.

checked the filter caps, all three FIFTY volts. i can't see all the markings clearly, i gotta do that in bright daylight.

i also tacked an inline fuse holder across the blown circuit breaker. it said the circuit draws .100 amps from the wall, i figure a 1 amp should be ok, the parallel courtesy outlet is rated for 3 amps, so i know its a bit high but should be fine as long as i don't throw a spanner in the works somewhere or something equally stupid.

we ARE talking me, here ;)

so anyways, after playing a bunch of guitar (i shouldn't have) with this damn finger <good for it AND my soul> and finally being asked super nicely by the young lady upstairs to turn the @#$% down i gave in for the nite.
i gotta be in playing shape, handwise, by thursday, by hook or by crook. the wyld west medicine show must go on! lol

i will endeavour to get it finished up tomorrow or the next day, for posterity sake

damn little purple berries.

been eating them for weeks now, haven't got sick once ;)

its got that kinda sound.

its hip.. its now... its 50 freekin years ago ;)

and ALL the kids are gonna be doing it, hick-a-doo-laaah

too many bad pop culture refs ina  row that are completely random, hippy needs sleep.
catch up more tomorrow.

peace out bro
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 06, 2019, 12:10:58 PM
btw, this is scary shit for a guitar player... this is a week into treatment. its WAY better than it was.


(https://i.postimg.cc/RN9kQZ4d/mrsa.png) (https://postimg.cc/RN9kQZ4d)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 06, 2019, 04:39:20 PM
Quote
the interaction of the two channels is really strange too, particularly after i
molested the fuzz slightly like we all knew i was gonna do.
just for shits n grins i tacked 3 .1u caps shunting across the .001u caps, which i guess is .101u there instead.
NOW the fuzz actually sounds fairly good, and if ya jumper the channels right you can get a real nice brownish overdrive out of it.
Cool.   There may be some issue with the phasing of the two channels through the mixer.   I haven't finished deciphering the channel preamps yet but channel 2 output driving the fuzz might be different to the channel 1 driving the mixer.

Quote
yeah, if we can un-neuter the tremolo and give it slightly bigger bollocks that could be fun, too. its pretty faint as is.
There's probably more than one way to do it.  The oscillator drives a gain stage for each channel so you could beef-up the output.  However, the resistor in series with the Vactrol is going to limit what you can do with just the drive.  The LFO is AC coupled.   If the tremolo is disabled by shorting the Vactrols the means decreasing the series resistors will mess with the non-tremolo gain.  You might need change the way the switching is done to disable it.

Quote
i gotta be in playing shape, handwise, by thursday, by hook or by crook. the wyld west medicine show must go on! lol
Good luck, looks like you should be able to do it.    (A few times I've sliced the tips of my fingers and it totally stops you from playing.   Bending ... huh ... just tears it open. )

Quote
btw, this is scary shit for a guitar player... this is a week into treatment. its WAY better than it was.
Yeah, I was the other thread.  That stuff is freaky.

BTW, I'm hoping to put up some info today.   There's no doubt it will need some fixing.   I'm having trouble bridging between the wiring lists you wrote out and the what I see on the schematic.   Maybe you will need to do another scan over it.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 06, 2019, 09:28:05 PM
cool!
not a problem, just let me know what ya need me to look at!

i'm gonna go mess with it a while... just got outta my coffin for the day. ;)

i'll permanently change them three caps i think, and remount the mixer board to the chassis etc..  while i got the switch buss taken off, i'll check where the wires go to. still not sure how the top boost works, i'm suspecting it may be part of the fuzz board. there's really nothing i can see on the switches themselves.

if my band wasn't so loud, i'd try it live tomorrow.. but i suspect it may be too noisy to use til i at least CHECK the filter caps... and i'd disconnecte a big cap to ground from the power supply i suspect was there to nuke rfi and stuff, i didn't fire it up after that so it may be quiet again tonite.

my girl gotta get up early, so limited time to really mess with it tonite. so i got time to check connections, etc.

more later. rock on bro!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 06, 2019, 09:59:00 PM
Quote
still not sure how the top boost works, i'm suspecting it may be part of the fuzz board. there's really nothing i can see on the switches themselves.

The top boost connects back the channel preamps.   There is a series resistor before the James Tone Control (Passive Baxandall)  The top boost shorts a cap across that resistor.    It's sort of like the bright switches on a Fender except it doesn't go across a pot.

I've nearly finished three boards.    Another two partially done.

In your wiring list you have the fuzz yellow wire pin 11 (your reversed numbering) going to channel 2 pin 17 (your reversed numbering).   From what I can see the tremollo is also connecting there to channel 2 pin 17.  Is that right?  If the tremolo switch short to ground that would take out the fuzz as well.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 06, 2019, 10:14:27 PM
i will check on that when i go down stairs, been dealing with ebay crap.

as i recall, yes, theres a few spots where socket pins share more than one connection.
the fuzz will still work if the tremolo is off or on, tho only on channel two, now.

before, there was a bit of "bleed" from the fuzz that came thru on channel one, now its gone since the mixers working right.

before that, i think the whole thing was "bleeding" thru the switch on the channel 2 only jack... if i opened the connection, it died, where as now the normal outs still work.

curiouser!
i will verify the wiring and post as soon as possible bro.
thanks!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 06, 2019, 10:34:18 PM
Quote
curiouser!
i will verify the wiring and post as soon as possible bro.
thanks!
I'm really struggling to make sense of the Reverb wiring.   I can match it up to the circuit.
There also a bit of ambiguity between the Reverb *Board* in/out  and the Reverb *Tank* in/out.
Can't see how the Reverb pot works either.

I might just post what I have in about 1/2 hr and see if you can kick it into shape
with the unit in front of you.

Oh,  on the fuzz there is an orange wire going back to the PSU (Fuzz board pin 8, with 1 at the key end).
Can't work that out either.


Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 06, 2019, 10:43:50 PM
hahah still trying to walk away from the computer, wheeling and dealing with a cat in oz on the bay.

the orange wire i'm betting i got wrong... not power supply, i bet it goes to the footswitching. i thought it went to the power supply, but i'm not sure how the hell the terminal block connections work. stuff goes all over, i dunno what goes thru the chassis, i will try and take pics to show what i mean.

i will check the wiring. i am betting any wires that totally don't make sense have to do with the footswitching.
stay tuned
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 06, 2019, 10:58:03 PM
Quote
i will check the wiring. i am betting any wires that totally don't make sense have to do with the footswitching.
stay tuned
I forgot about those.  Yeah!  where do they fit into the story. :icon_mrgreen:

Here's the stuff which is nearly there,



(https://i.postimg.cc/WqL87PXC/Ovation-K6001-3ofx-Fuzz-Board-V10.png) (https://postimg.cc/WqL87PXC)


(https://i.postimg.cc/XrHgz5sw/Part-Designators-Fuzz-Board-top-view.png) (https://postimg.cc/XrHgz5sw)


(https://i.postimg.cc/SXHfyhFR/Ovation-K6001-4ofx-Reverb-Board-V10.png) (https://postimg.cc/SXHfyhFR)


(https://i.postimg.cc/nXz4BznM/Part-Designators-Reverb-Board-top-view.png) (https://postimg.cc/nXz4BznM)


(https://i.postimg.cc/SnvWrhKd/Ovation-K6001-7ofx-Mixer-Board-V13.png) (https://postimg.cc/SnvWrhKd)


(https://i.postimg.cc/RqBbfcyF/Part-Designators-Mixer-Board-top-view.png) (https://postimg.cc/RqBbfcyF)



(https://i.postimg.cc/dDjN9hc9/wiring-v10-partial.png) (https://postimg.cc/dDjN9hc9)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 06, 2019, 11:23:43 PM
(https://c8.alamy.com/comp/BK7BFN/cooked-sausage-on-fork-BK7BFN.jpg)

holy shit rob!!
 you been busy!!

i STILL haven't made it downstairs. lol look good!
i'm-a gonna check 'em real quick

the only thing i see weird is the preamp board picture appears to be mirrored from whats actually there.
but i just realized its seeing "thru" the board. looks good.
i can verify values n crap too.
printed the connections you posted so i can check.

hopefully, i can get down there now!! ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 06, 2019, 11:48:52 PM
Quote
i STILL haven't made it downstairs. lol look good!
i'm-a gonna check 'em real quick
No hurry.

I've traced the channel preamps and the tremolo but I haven't drawn them up.
Trying to make sense of the external connections *and* the schematics is really killing me  :o :icon_eek: :o :icon_eek:
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 07, 2019, 01:31:13 AM
ya got popcorn, and a cold beer ready?
blaze a yule log and gimme a couple minutes.
dude, we're just about there.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 07, 2019, 01:52:20 AM
OK!

to answer questions first

does fuzz socket pin 11, yellow wire, connect to channel 2 socket, pin 17?

yes

does trem socket 3 also connect to chan 2 pin 17?

yes

fuzz board, orange wire, fuzz socket pin # 8, (1 at key end) to FOOTSWITCH orange, fuzz

channel 1 , socket pin 5,l-r,  orange wire to tuner socket # 10, key 2 l-r

footswitch connections.... i got extra pins, so i can run led's in it and power them remotely ;) 6 pin DIN, only 4 used...
orange  fuzz
green  trem
blue    reverb
black  ground

trem oscillator vactrols
GE 6535 appear to have three connections
i will get proper values at another time...

reverb tank appears to be standard accutronics type, kinda "gray" rather than laquered only thing i see on it for numbers is 1122 stamped on top. it might have more inside, i'll open the plate and look at some point.

fuzz board wiring appears to be right i think

reverb is like this, as per your picture you posted

1   reverb out, tank recovery, black rever tank out shield
2 n/c
3  blue, not +v, reverb footswitch
4  rev lev 2,  tank recovery, reverb blend pot #2
5  key
6  reverb out signal? yes  is this tank input? no. this is tank output tip
7  rev lev green.... does really go to rev pot? yes, rev # 3
8  mixer 11 purple   ...... i gotta look at that again, its weird, its ultimately part of the switching, but after the pots.
9  +v orange +vr1  psu
10    rev in (hot)  reverb in   does this go to mixer pin 8? (blue wire) YES
11 rev in grnd /shield tank drive out , reverb tank input (hot) yes
12, grnd, black, mixer pin 8? not 8, pin 8 is the blue one. i gotta look fresh.

stay tuned, if yer still out there, i gotta scan a page of notes for the power supply.
be right back.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 07, 2019, 02:08:35 AM
i'm betting the transformer output is more like 25v-0-25, not 50. maybe even less, b+ seems to be about 21v.
maybe even 12-0-12... center tapped.
resistors between the can pieces are 1k. the 10,000uf cap only uses one of its three sections, there's two left over
the 100uf cans are double caps
CLR for the pilot lamp 680r to star ground
all the case connections of all the power supply caps are connected, to the ground shown on the first 100u cap
the terminal block is a double sided one, the connections on one side go thru to the other.
diodes i can't read the markings, bullet shaped kinda, about the size of a pencil diameter. not sure which side is cathode, but one side of each is black, i marked it on the crappy drawing
i didn't add the power on or phase reversal switches,
the power on is just a spst
the phase reversal is the typical x pattern dealio
i DO need to finish tracing the last couple switch connections for the tremolo and top boost, but other than that, we have now
gone all the way thru the circuit, other than proper values on some of the boards.
i will start working up graphics of cap values for the whole mess, i think you can probably see the resistor values better than i can.

we done nailed it. well done, everyone!


(https://i.postimg.cc/0KRDxK5J/ps-notes.png) (https://postimg.cc/0KRDxK5J)

my widdle bwain hurts. i don't think its in kansas anymore. ;)

little bit further, to get farther back...

its hip, its now, its 50 @#$%in years ago lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 07, 2019, 03:29:36 PM
Wow heaps of info.  Thanks.

Quote
my widdle bwain hurts. i don't think its in kansas anymore

Now mine does too.   

Didn't get too far yesterday.   I just rechecked the trace of the preamp and fixed a few bugs.  Volume control is a bit whacky.

I'll check over all that stuff you posted in a bit.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 07, 2019, 03:38:09 PM
i think the volume control is set up kinda like a pan. i can nab ya pix if ya need them.
gotta gig tonite tho, so won't really be able to do much til i get home at 3am or sometime tomorrow.

look forward to buttoning it up. wondering about adding some relays, so i can switch them 3 caps in and out remotely. never really worked with them before, but thinking i may be able to steal a b+ voltage for the footswitch leds and send it down the cable to the switches...and still have one wire left over to power the relays with.

this is way above my paygrade lol

i'll check in later. later!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 07, 2019, 03:47:53 PM
Quote
i think the volume control is set up kinda like a pan. i can nab ya pix if ya need them.
It looks like the input sockets wire to one part of the volume pot.

Quote
gotta gig tonite tho, so won't really be able to do much til i get home at 3am or sometime tomorrow.
How did your finger go?

Quote
look forward to buttoning it up.
Yes, the fixing job is done.     

We don't need to back-engineer the thing to the point of cloning it - unless you want to.    Most of the details have been captured.  If anything happens to it you have a good map to fix it.

Quote
wondering about adding some relays, so i can switch them 3 caps in and out remotely. never really worked with them before, but thinking i may be able to steal a b+ voltage for the footswitch leds and send it down the cable to the switches...and still have one wire left over to power the relays with.
That will work.   If the supply is 24V you could use 24V relays.  Another way is Vactrol, like some of the old Mesa Boogies.

Quote
this is way above my paygrade lol

Nah,  you could do it easily. 

Quote
i'll check in later. later!
No, problem - same here.

BTW, the channel preamps have some sort of "voicing" EQ build-in on top of the tone controls.   The tone controls aren't quite normal either they have an interesting twist.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 07, 2019, 03:55:10 PM
input wires go right to the socket for the channel, each to its own pin. the ground from the jacks goes to them i think, but i will have to look. i don't think the volume controls come off the inputs, but off the outputs of the channel.
not sure tho, i will check more closely when i get home.

relays. hmm! maybe it would be cool! but i think its easier to just hardwire the new caps in, and use the onboard fuzz modded. it sounds about 20000000000000000000x better i think.

duty calls.. will check back when i can. probably in the wee hours. entirely too sober for a formerly lush musician lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 07, 2019, 04:01:16 PM
Quote
input wires go right to the socket for the channel, each to its own pin. the ground from the jacks goes to them i think, but i will have to look. i don't think the volume controls come off the inputs, but off the outputs of the channel.
not sure tho, i will check more closely when i get home.
I think the problem was the inputs do go to their own pin (2nd and 3rd pin from one end) *but* on the board it is a dead-end.   The signal has to come out on the 4th pin (from the same end).  That's where I think it goes to the volume control. Then comes back from the volume control and into the 5th pin (from the same end).
There's also a 220k resistor stuck across pins??? of the Vol pot.

The manual talks about some volume control scheme to reduce clipping.

I was trying to work that out yesterday but only got this far.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 07, 2019, 05:11:47 PM
k bro,
here's a bunch of pics of the volume control and how they are wired. i don't have the time right now to be able to physically trace them, but this way you can see how they connect. the tone and volume controls for channel one and two are wired identically, same color codes. the cap off the dual pot is .o47u
think of it maybe like the klon drive control, the double thing i forget, been years.

the 220k resistor is between wiper of top pot, and pin 3 of the bottom one.
there are multiple connections in some cases to the volume pots. its really @#$%in weird.

(https://i.postimg.cc/8syn8600/Pic-02072019-002.jpg) (https://postimg.cc/8syn8600)

(https://i.postimg.cc/KRwqjyF7/Pic-02072019-003.jpg) (https://postimg.cc/KRwqjyF7)

(https://i.postimg.cc/FdrG8rgv/Pic-02072019-004.jpg) (https://postimg.cc/FdrG8rgv)

(https://i.postimg.cc/94jLPtDr/Pic-02072019-005.jpg) (https://postimg.cc/94jLPtDr)

(https://i.postimg.cc/xJ6gSwtz/Pic-02072019-006.jpg) (https://postimg.cc/xJ6gSwtz)

(https://i.postimg.cc/WdZ9JfbB/Pic-02072019-007.jpg) (https://postimg.cc/WdZ9JfbB)

(https://i.postimg.cc/zH37DxcP/Pic-02072019-008.jpg) (https://postimg.cc/zH37DxcP)

i tried to get it from as many angles as possible without having to re-disassemble it. t minus 1 hour and 50 minutes til i gotta go.

hope they help. i can trace 'em all too if need be again.
be right back with a schem for the volume pot
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 07, 2019, 05:43:34 PM
ok, here's a qnd schem for the volume pots, and how they hook up and where.
the key is the key. its not on the left early with the channels, its pin 15, left to right, from the backs of the boards.
sorry i was unclear before, my first attempt at tracing a circuit like this. ;)
i also probably confused pinout of the damn pots. i forget constantly which orientation is right, and have found nothing is necessaril right ;)

i think the way they wire the pot, it takes advantage of the taper of each half of the pot. or something. did i mention its weird?

;)


anyways...


(https://i.postimg.cc/HrC6C9Td/ovation-9001-preamp-vol-deets-1.png) (https://postimg.cc/HrC6C9Td)

liddle bid clozer, bud!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 07, 2019, 05:44:53 PM
Quote
here's a bunch of pics of the volume control and how they are wired. i don't have the time right now to be able to physically trace them, but this way you can see how they connect. the tone and volume controls for channel one and two are wired identically, same color codes. the cap off the dual pot is .o47u
think of it maybe like the klon drive control, the double thing i forget, been year
Great, thanks a lot.

With that stuff and the big list you posted a couple of posts back I've got a heap to go on with now.  :icon_mrgreen:
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 07, 2019, 05:46:35 PM
Quote
sorry i was unclear before, my first attempt at tracing a circuit like this. ;)
i also probably confused pinout of the damn pots. i forget constantly which orientation is right, and have found nothing is necessaril right
Cool, that saved me quite a bit of unraveling.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 07, 2019, 06:23:06 PM
lol..
i just memorized in guitars, from the back with the pins sticking up and the shaft pointing down, the furthermost left one goes to ground lol.

that said tho, i've seen it written as pin 1 AND pin 3, and seen it in schematics like that, too, so... beats me.

wanna really go insane? unravel the mysteries of why we only work with uf, nf and pf, and we're off by a factor of 1000 on each one from reality lol. there's a BUNCH OF WEIRD VALUE CAPS!! LOL

anyways.. gotta button up this sg i'm bringin tonite for a change from the usual les paul or firebird.

check in when i get in. later bro
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 07, 2019, 06:33:45 PM
Quote
i just memorized in guitars, from the back with the pins sticking up and the shaft pointing down, the furthermost left one goes to ground lol.
that said tho, i've seen it written as pin 1 AND pin 3, and seen it in schematics like that, too, so... beats me.
Yes the world is a mix-up place.    I remember watching this video on Bourns "Professional Series" pots.   It was the most mixed-up piece of rubbish I've ever seen.   Their documents sucked as well.  Basically you couldn't work out the tapers of their pan pots at all.  So much for "Professional" info.

Quote
wanna really go insane? unravel the mysteries of why we only work with uf, nf and pf, and we're off by a factor of 1000 on each one from reality lol. there's a BUNCH OF WEIRD VALUE CAPS!! LOL
Sometimes I can fend off that stuff but it's sure a pain.

Quote
anyways.. gotta button up this sg i'm bringin tonite for a change from the usual les paul or firebird.
You have so much cool stuff!   I've tried to downsize my life but it ends-up being too much and not enough at the same time  :o.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 07, 2019, 06:39:28 PM
well, i was down to about 40 guitar until les paul #25 got bought today lol.

i am a total gear whore. at one point, i had LITERALLY 70 of my own, and 38 for sale. 108 is the most i've had at once.

way too many. its bad.

i'm down to maybe, 100 pedals now...lol..

maybe...14, 15 amps...

and a 24 space rack

you know, just the basics .......

my name is pink and i am a gear horder with chronic GAS
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 08, 2019, 12:23:32 AM
Quote
well, i was down to about 40 guitar until les paul #25 got bought today lol.

i am a total gear whore. at one point, i had LITERALLY 70 of my own, and 38 for sale. 108 is the most i've had at once.

way too many. its bad.

i'm down to maybe, 100 pedals now...lol..

maybe...14, 15 amps...

and a 24 space rack

you know, just the basics .......

That's a crazy load of stuff.   Do you have to carry out a stock take once a year and report to the shareholders ;D.

I'm probably not going to get far today.  We have visitors.

One thing I can't account for is Reverb-Blend pot terminal 1.      Reverb-Blend pot terminal 3 has a weird connection, it goes to ground when the reverb is on full!   So there must be a weird connection going on.  I can think of one but without Reverb-Blend pot terminal 1 I'm just making up stuff.


Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 08, 2019, 02:07:20 AM
i will take a look at it tomor....err... today later and verify what connects where to that. i still gotta get the switches anyways.
no worries or hurries. i'm faily lazy ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 08, 2019, 03:34:19 PM
Quote
no worries or hurries
Yeah, no worries.

I'll leave the Reverb for a bit and see if I can get the channel preamp(s) drawn up today.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 08, 2019, 05:46:05 PM
no problem bro,
we gotta get the dang switching done up anyways to make sense of it all... til we do, we're not gonna know whats what, as the color code of the wiring changes. i THINK each channel is switched before the reverb, to me makes the most sense.
easy way to try is to play something and kill the switch and see if it splashes over. if it does, it will be pre-verb, if not, post.

all will be revealed. i gotta wake up some more, and i'll head for the dungeon!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 08, 2019, 11:12:10 PM
Here's what I have so far. 
I've created a pic for the designators for Ch1 (and Ch2) use the prev designator pics for the other boards.
Updated schematics.

(https://i.postimg.cc/jntDQpZS/Part-Designators-CH1-Board-top-view-xray.png) (https://postimg.cc/jntDQpZS)

(https://i.postimg.cc/BXZgJk43/Ovation-K6001-1ofx-Channel1-Board.png) (https://postimg.cc/BXZgJk43)

(https://i.postimg.cc/3kdFvGkb/Ovation-K6001-2ofx-Channel2-Board.png) (https://postimg.cc/3kdFvGkb)

(https://i.postimg.cc/dDwR9p7C/Ovation-K6001-3ofx-Fuzz-Board.png) (https://postimg.cc/dDwR9p7C)

(https://i.postimg.cc/hfG9km1P/Ovation-K6001-4ofx-Reverb-Board.png) (https://postimg.cc/hfG9km1P)

(https://i.postimg.cc/FYd0RQ6M/Ovation-K6001-7ofx-Mixer-Board.png) (https://postimg.cc/FYd0RQ6M)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 08, 2019, 11:14:33 PM
The volume control at the input is weird.  Loads the pickups a lot too.

The way the fuzz connects around to the circuit is weird and so to is the fact the fuzz circuit is driving the the emitter output where the tremolo

If I saw those things on a schematic I would think it was wrong!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 09, 2019, 03:16:19 AM
holy shit dude you been busy!!!
me too... took me like, two hours or so to figure out how the heck to re-attach the mixer board to the switch strip without unwiring the whole mess. finally managed to get the screws in.. THAT was fun... used double sided sticky things finally, squished in to hold the screws, magnetized a little jewler screwdriver to get the locks and nuts on... discovered if i stuck the screwdriver thru the lock and nut, and held 'em in place with my finger, i could put the tip right on the screws and drop 'em onto it. clever, huh? yeah, took me hours, lol HOURS, and worked way better in theory than in practice! finally got 'em on a couple threads, removed the sticky crap and screwed 'em in and reinstalled the switching strip.
tightened up all the card retainers, used some hyper strength luthier grade cyanoacrylate to glue the broken mount back to the chassis, permanently mounted them three 100n caps to the fuzz  :icon_twisted: :icon_twisted: :icon_twisted: :icon_twisted: :icon_twisted: :icon_twisted:
it had to be done. the fuzz is cool now.

depending on how hard ya drive the channel two channel appears to determines how hard ya drive the fuzz.
its wicked cool.

then i took a look at my princeton and changed all the freekin preamp tubes. turned out # 1 needed the socket cleaned. so i fixed that. just a side thing, but now it will sound a lot better. i may start gigging with it.
pulling the trigger on stuff to build a footswitch for the fuzz reverb and trem. i gotta box already. will run the led's off the power supply, probably give them their own hot and ground to keep noise down.

the fuzz now overpowers the tremolo, which is kinda cool, cuz as the fuzz decays the clean trem sorta fades in. kinda trippy. sounds a lot like the princeton, but kinda weak.
if it can be given more balls, well, this IS 2019 and we're cookin with 'lectricity, son!

the thing is nice and clean, everything works now. the tuner appears to have its level controlled by volume 2, and it needs to be the proper level for the eye to wink ;) of course the bloody thing is LOUD AS @#$% so you'd need to put it on standby at that point. i must have bumped the trimmer inside, cuz all the way up isn't a perfect G any more.
the guitar doesn't come out the outputs when the tuner is on. it did before, so apparently, i fixed or broke something.

the reverb saturates beautifully and is deep and dank as the patchouli stenchin off some hipster's dungeon.
surprisingly quiet. when the preamps are overdriven, they do it fairly gracefully. when you jumper them together as i said, into channel 1 # 2 and then jumper chan 1 #1 to chan 2 #2 it seems to cascade them somewhat, so the channel one controls how hard ya drive it, channel two you can crank til it sounds good, and then crank the fuzz just barely on and its bloody @#$%in perfectly brilliant.

when i do a demo for this sucker, watch, they'll come popping outta the woodwork. or dumps. one or the other. from 35 dollar fringe interest items no one cares about to next boot-tweek thousand dollar gizmotron. its hip! its now! its 50 @#$%in years ago!
lol

enough blatherskitin' the balderdash.. here's the reverb pot wiring, and socket keys ... compare to the pics of the boards if any question about orientation, i guess.


(https://i.postimg.cc/f3DSwhqw/rev-pot-wire-socket-keys.png) (https://postimg.cc/f3DSwhqw)

and here is the switching matrix <not including the reverb> and the power supply side of the terminal block, as two of the wires from the tuner circuit connect there.



(https://i.postimg.cc/CnYQ75m3/switches-term-block.png) (https://postimg.cc/CnYQ75m3)


i gotta digest the pics tomorrow when it ain't 3:12 am lol. burnt hippy!

dude. you so totally rock. this is cool as hell!

i'll get all the values off stuff asap and mark 'em on the schematics.
but i think this sucker's done, i mean, we've been thru every aspect of the circuit now i think.

AND the original one not only lives again, and sounds great, now its gotta FUZZ that don't SUCK.

the top boost acts a little different with the bigger fuzz caps, too, but, hey, its better this way.

trust me. i'm a fuzz magician. ;)

who needs sleep and is babbling,.... lol nite rob
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 09, 2019, 07:33:23 PM
Quote
me too... took me like, two hours or so to figure out how the heck to re-attach the mixer board to the switch strip without unwiring the whole mess. finally managed to get the screws in..
Those fiddly jobs can take up time.

Quote
depending on how hard ya drive the channel two channel appears to determines how hard ya drive the fuzz.
its wicked cool.
It's good you can improve it.  We know a more now than the 60's so no point holding onto the old.

Quote
then jumper chan 1 #1 to chan 2 #2 it seems to cascade them somewhat, so the channel one controls how hard ya drive it, channel two you can crank til it sounds good, and then crank the fuzz just barely on and its bloody @#$%in perfectly brilliant.
I wonder if some of the coolness comes from the higher supply voltages?

Quote
hen i took a look at my princeton and changed all the freekin preamp tubes.
You must have a small fortune of tubes tied up in all those amps you have.

Quote
enough blatherskitin' the balderdash.. here's the reverb pot wiring, and socket keys ... compare to the pics of the boards if any question about orientation, i guess
Thanks for drawing that up.     When I take that drawing, the schematics, and the previous wiring lists, then try to put it together it all falls in a heap.  Only a few things line up and I don't even know if those are correct.   I started to draw a picture but there were so many ambiguous connections I gave up.   One problem is your mixer numbers and my schematic numbers don't quite line up.

Quote
and here is the switching matrix <not including the reverb> and the power supply side of the terminal block, as two of the wires from the tuner circuit connect there.
We should try to work out the switching   Initially I though  you might try to piggy back something onto it but maybe you are better off just doing you own thing for the mods.

Quote
'll get all the values off stuff asap and mark 'em on the schematics.
but i think this sucker's done, i mean, we've been thru every aspect of the circuit now i think.
Yeah the values should be easy since I've marked out the designators.    I'm still not confident about board interconnections.

Quote
AND the original one not only lives again, and sounds great, now its gotta FUZZ that don't SUCK.
the top boost acts a little different with the bigger fuzz caps, too, but, hey, its better this way.
trust me. i'm a fuzz magician.
I suspect you could spend weeks tweaking it  ;D.


Not sure if I'll get anywhere today.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 09, 2019, 10:50:07 PM
Quote
me too... took me like, two hours or so to figure out how the heck to re-attach the mixer board to the switch strip without unwiring the whole mess. finally managed to get the screws in..
Those fiddly jobs can take up time.

Quote
depending on how hard ya drive the channel two channel appears to determines how hard ya drive the fuzz.
its wicked cool.
It's good you can improve it.  We know a more now than the 60's so no point holding onto the old.

only thing i can see needing improvement would have been the fuzz. i AM curious about the extra connections for it, but haven't had a chance yet to look at the schematic and compare it.



Quote
then jumper chan 1 #1 to chan 2 #2 it seems to cascade them somewhat, so the channel one controls how hard ya drive it, channel two you can crank til it sounds good, and then crank the fuzz just barely on and its bloody @#$%in perfectly brilliant.
I wonder if some of the coolness comes from the higher supply voltages?[/quote]

it could i guess, but i think the fuzz is only running on 10v, i don't think it would matter if it were run at 9v. the preamps and stuff are a bit higher tho, so yeah, some more headroom maybe. its definitely loud and pretty clean!


Quote
hen i took a look at my princeton and changed all the freekin preamp tubes.
You must have a small fortune of tubes tied up in all those amps you have.[/quote]

funny thing is, i only own a handful of "tube" amps.. princeton, silkyn, pro reverb and a couple weird things from the 60's i gotta restore one day... the cyber twin is hybrid, all the rest is solid state, and largely ancient and germanium.
i use russian tubes for the outputs, i buy 'em in matched quads for about 40 bux shipped, and then for preamp tubes, depends on whats around and what they go for. if i can't get a good enough deal online, my bud mikey hooks me up a couple points over his wholesale cost. sometimes i throw him a fuzz or something. <he is a real mutha!!> on the forums he's "agitprop"



Quote
enough blatherskitin' the balderdash.. here's the reverb pot wiring, and socket keys ... compare to the pics of the boards if any question about orientation, i guess
Thanks for drawing that up.     When I take that drawing, the schematics, and the previous wiring lists, then try to put it together it all falls in a heap.  Only a few things line up and I don't even know if those are correct.   I started to draw a picture but there were so many ambiguous connections I gave up.   One problem is your mixer numbers and my schematic numbers don't quite line up.[/quote]

well, the mixer has 12 connections, and there's more than one wire to some of them. some of the connections are hard to see in the pictures, for sure. some are wicked close together, too.
perhaps the thing i need to do is to go back, and re-draw the connections to the individual boards. i think whats messing you up is the keys, as you'd like to think they'd be oriented the same depending on board, but they're not. the PREAMP keys are the same. but like... next in line, you have the fuzz board, trace side towards you from the back. pull the fuzz card, and suddenly the reverb board, component side, is staring at you. so i guess i'm gonna have to try and digest it from here and draw it up... at least the board, number of connections, which slot the key is in from left to right <or, as the case may be, from front to back>
and where each connection goes to and terminates.
i swear, its probably easier than it seems, and i must take the blame for that. when i first started pulling stuff, i just arbitrarily counted the slots, and not necessarily left and right from the same orientations as i was spinning the chassis around trying to see where all the wires came and went. i think i can do that, and will try and start on it tomorrow. hopefully, that will make things a little less @#$%ed up to try and grok.


Quote
and here is the switching matrix <not including the reverb> and the power supply side of the terminal block, as two of the wires from the tuner circuit connect there.
We should try to work out the switching   Initially I though  you might try to piggy back something onto it but maybe you are better off just doing you own thing for the mods.[/quote]

the ONLY thing i have modded was tacking 3 caps on in parallel with the original ones on the fuzz board. no other modifications have been made at all. the switching is completely documented. the switching is also documented,
there's a 6 pin din plug, and 4 connections are used... one for the fuzz <orange> one for the reverb <blue, i think> and one for the trem <green, i think> looks like when NOT in use, each module is simply shorted to ground with the footswitch. each color wire eventually connects back to each circuit card, but there is no channel switching.  the top boost switches aren't footswitchable. i DID draw out where the wires from each switch go to... i would say, let me try and draw up how it goes together and post it, take a couple days off where ya aren't seeing this pig in your sleep ;)


Quote
'll get all the values off stuff asap and mark 'em on the schematics.
but i think this sucker's done, i mean, we've been thru every aspect of the circuit now i think.
Yeah the values should be easy since I've marked out the designators.    I'm still not confident about board interconnections.[/quote]

i'm confidant with the board connections i have in my notes, i traced everything visually, and used the continuity beeper in my meter to double and triple check everything. the parallel connections thing is whats making it so bloody weird!!!



Quote
AND the original one not only lives again, and sounds great, now its gotta FUZZ that don't SUCK.
the top boost acts a little different with the bigger fuzz caps, too, but, hey, its better this way.
trust me. i'm a fuzz magician.
I suspect you could spend weeks tweaking it  ;D.[/quote]

probably, but i don't see a need to, really. with the bigger caps it sounds REALLY good, and has more than enough balls for what i would use. maybe a tad less harsh would be good, or a smidge more sustain, but it's actually....well,....GOOD now. ;) i will try and get some vid soon,  hard to do when g is home on the weekends, she doesn't "get it" and it just kinda annoys her.
;)



[/quote]
Not sure if I'll get anywhere today.
[/quote]

no worries!! you've been kicking ass, take it easy for a bit, and then come back to it if ya want to. no hurries here. pretty sure i can at least get all the board connections etc done from here.
do ya think its better to draw them, or just list them?
if just listing, it may be easier.

like..
chan 1 socket
1
2
3
4
5
6.....etc etc

fuzz pot 1 to blah blah
fuzz pot 2 to... stuff like that.

i can make sure all the key spots are notated, and which side of the board they apply to, which i think is a major confusion point.

no worries!! we've come this far, i think if i can do that it will be a lot easier to make sense out of.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 10, 2019, 01:46:09 AM
I'll get back to this tomorrow.  Too much for my little brain today - got up at 3:30am.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 10, 2019, 02:43:47 AM
ouch!
get some rest dude!!! yer as bad as me!!

i figured out how things got lost in the translation.  the preamp board connectionsto the socket on the "xray" board you posted are actually backwards somehow.

it looks like you're looking at the components and seeing the traces thru the board. that part is right.
but the components face away from you inside the amp when you open it up.
so when you look at it from behind, the sockets go from close to you to further from you, or left to right. in that case, the locator pin is actually # 15, not pin 4. somehow our pinouts got reversed in understanding. you were thinking left to right looking at the component side of the board, but i was going the opposite cuz the boards face the other way.

i know thats too much to lay on yer head right now lol but if ya do it my way, all the connections connect together and add up.

to further add insult to injury, the fuzz board faces away from you with the components. so in that case, locator pin is socket #10.
the reverb board is behind it. the components on that face you. in that case, the locator pin is socket #5

all of the above left to right, or closest to furthest in the case of the preamp board, the tuner and the tremolo.
further, the trem and tuner orient the opposite way from the damn preamp boards.  all face the reverb fuzz and mixer in the middle, with the component sides.

the mixer, from the back
left to right

pin 1, orange,  channel 2 output only, normally closed switch to tip of channel 2 only jack

pin 2, brown, i have to check that one again, or put it against the rest of the data when i try n put the mess together

pin 3, dark brown, channel 2 output only, tip/hot

pin 4, blue, reverb socket pin #10

pin 5, light brown, channel two volume # 3 (1?)

pin 6,  black, tuner on/off switch pin  #5

pin 7, 3 connections all black, all ground plane of mixer board
a :  channel 1 & 2 parallel output ground
b:   channel  1 & 2 volume  pin # 1
c:   reverb socket # 12 and reverb pot # 1

pin 9, red.....? gotta find it

pin 10 , double connection, red
a: channel 1, socket # 6
b: channel 2, socket # 6

pin 11 purple, reverb socket pin #8


EDIT: @#$%, i have to look at the board again and check the dang wires. again, our wires our crossed, on the parts designator pic you posted, we are numbering the board connections, again, exactly opposite, and apparently i screwed up when i was writing the wires.

again, the board goes, left to right, starting with the orange wire, and ending with the purple one. the components/switches facing away from you, like when looking in the amp.

the pic of the mixer is actually mirrored from what i'm trying to describe, so its gonna be way more confusing. we gotta stick with just one way to try and describe this, cuz right now stuff's getting backwards from what i'm trying to document for you to be able to sort this mess. so ... stay tuned. let me get this shit all in one post with all the data and all the connections correllated.

hang in there bro! ;)



i'm gonna scan my notes from tonite, and post them in a little bit and call it a nite.
i wrote down all the values for the resistors and caps on both preamp boards,
and yes, all q's bc109c AFAICT

two much to try and type. i'd be here til tomorrow afternoon. ;)


Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 10, 2019, 03:02:44 AM
what i mean is, on the mixer, what i call pin 1 you call pin 11, on the channels, what i call pin one, you call pin 18.

no worries. we'll get the mess sorted out. peace!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 10, 2019, 04:16:45 PM
Quote
get some rest dude!!! yer as bad as me!!
Yeah, probably because I've been drinking more coffee lately.  Today was 4:30am  :o

Quote
i figured out how things got lost in the translation.  the preamp board connectionsto the socket on the "xray" board you posted are actually backwards somehow.
Yes, the trace side are xray pics looking *through* the board.   I use those for tracing and checking.   I always do that when I tracing ckts.  It's much easier to match-up the pics of the parts with the traces.    Maybe added to the confusion.

There was a pattern to the numbering I used:
- Pin 1 is always closest to the key (doesn't matter which side you look at the board)
- It turns out, when looking from the component side with the pins at the bottom, all the keys slots are on your left. The mixer board doesn't have a key so I number it with pin 1 on the left to be the same as the others.

The mixer is a problem because it has eyelets/posts and some solder points.  I assigned a number to each connection whatever the type.

Quote
i know thats too much to lay on yer head right now lol but if ya do it my way, all the connections connect together and add up.
I'm sure all the numberings match-up in their own universe. It's funny how simple things get mixed up.

Quote
the mixer, from the back
left to right

OK thanks, I'll see how that matches up.    Hopefully it is just reverse numbered.  I know I've got orange on the right (when looking at the components with the connection at the bottom).

Quote
what i mean is, on the mixer, what i call pin 1 you call pin 11, on the channels, what i call pin one, you call pin 18.

no worries. we'll get the mess sorted out. peace!

Yep, no worries.   I think I've got more than enough to sort out  :icon_mrgreen:

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 10, 2019, 05:11:30 PM
sorry, the confusion all stems from ME.
i am gonna stick with the way i numbered stuff, all of it, as to try and reverse stuff after the fact will make us all @#$%ing crazy, especially places where there's more than one connection.

as of now, i have all the sockets numbered and described to make sense, with wires and where they go, etc.
also have BOM for both channels, fuzz, and reverb. getting ready to do the BOM for the tremolo now.
have diagrams of each channel, how the wiring is on the stacked volume pots, i call them top and bottom, as rv1 or 2 is too easy to confuse with ReVerb 1 and 2...
also rechecked and retraced the mixer,
left to right from the back, orange wire to pin 1, purple wire to pin 11
will do the terminal block too, it passes thru from one side to the other apparently.

i am numbering it 1-6 a for the left side, top to bottom, and 1-6 b for the right side, top to bottom. center will be 1 2 and 3. i will designate whether its on the a side <where the power supply stuff comes in> and b side <where the pcbs are>

i got the switches all drawn up too, will include that
not gonna bother documenting the tuner yet, if ever.  we probably should, for a historical stance, but @#$%it, ya know?
lol

so anyways, will have PAGES of info, all correllated and triple checked for connections for the whole damn mess coming at you soon. when i get done with the trem board and term block, its time for breakfast and a break... been writing since noon lol

stay tuned brother, we got this shit!!!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 10, 2019, 06:33:12 PM
trem board with parts values designated.


(https://i.postimg.cc/SYpLxPjL/trem-board-parts-designation.png) (https://postimg.cc/SYpLxPjL)

all the other stuff is DONE other than the BOM etc for the tuner/oscillator

will scan it and upload after breakfast <at 6:26pm> and <bones> a break.... stay tuned for the mother load of crap
terminal blocks and power supply with transformer voltages and pots BOM
fuzz and reverb sockets with pin designation and all connections and keys
channel 1 & 2 sockets with pin designations and all connections and keys
chan one bom with socket and pin locations and key
chan 2 '   '''''      '' ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
chan 1 pots and jacks details and wiring
chan 2 pots and jacks details and wiring
mixer pins wiring and pin designation and all connections
trem board socket wiring and pin designations with key for all connections
fuzz BOM
VERB BOM
TREM BOM

AND BELIEVE IT OR NOT, OTHER THAN THE TUNER, THATS THE WHOLE @#$%ING CIRCUIT!!
will upload soon bro. peace!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 10, 2019, 06:36:54 PM
Quote
sorry, the confusion all stems from ME.
i am gonna stick with the way i numbered stuff, all of it, as to try and reverse stuff after the fact will make us all @#$%ing crazy, especially places where there's more than one connection.
It didn't come from you!  There's no right answer.  We just happened to do it differently.   For all we know the original schematic could have a unique number (from 1 to 50, or whatever) for every wire point ;D.

The important thing is to pick something and we both use the same thing.  No prob for me updating the numbers.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 10, 2019, 06:57:11 PM
even got the transistors bro,... 2n3566, npn's. WE GOT THIS!!!

https://alltransistors.com/transistor.php?transistor=3344

waiting for gineen to finish making dinner. ooops. breakfast gotta wait lol

the q's on the mixer, the trem and reverb all are the 2n3566, except the third transistor on the reverb board, which is
mmps6517

https://www.onsemi.com/pub/Collateral/2N6515-D.PDF



one of the q's on the reverb board, the one on the component side top left, is mounted sideway with what appears to be an 18r 1 watt resistor where b should connect.

all the other transistors are bc109c. have not looked at the tuner yet.

gonna be a bit til i can get my scan on... but got a LOT done today.. 9 pages of fresh notes!! ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 10, 2019, 08:12:50 PM
Quote
trem board with parts values designated.

even got the transistors bro,... 2n3566, npn's. WE GOT THIS!!!
Cool.  Somehow I didn't see you trem board post before.

I worried about posting stuff today it could come out a bit skewed like my mind is today.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 10, 2019, 09:14:53 PM
get yourself a good nites sleep, and check back tomorrow. by then, i'll have everything scanned and uploaded!
gonna go down the dungeon and re-assemble the amp, and let the magick smoke out <of me lol> then i'm gonna scan and upload the whole mess.  some of the earlier pics and notes may still be useful, but the new batch will be the stuff to go by  i think.

some notes as to weirdness.. the original drawing of the power supply is a bloody mess, for sure... so i drew it a lot simpler. the original drawing is good cuz it shows HOW it all connects, as ya look at it, but its wicked hard to follow. now it should be much simpler. i hope. ;)

i can always check on anything if you find any discrepancies, i'm gonna wait to mount it back in the case til i'm sure we got everything.

also gonna take a peek at the fuzz and see if i can whip up a standalone version of it, probably on vero knowing me.

stay tuned bro!

and take the nite off, lord knows, you deserve it!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 10, 2019, 10:49:29 PM
ok, here we go bro... all the dirt~~

channel 1 and 2 socket wiring

(https://i.postimg.cc/5YfwZ2NB/chan-1-and-2.png) (https://postimg.cc/5YfwZ2NB)

chan 1  BOM

(https://i.postimg.cc/7J6SZtzb/chan-1-bom.png) (https://postimg.cc/7J6SZtzb)

chan 1 pots n sockets

(https://i.postimg.cc/yk207P8Y/chan-1-pots-n-sockets.png)
 (https://postimg.cc/yk207P8Y)

chan 2 BOM
(https://i.postimg.cc/xk3myVyc/chan-2-bom.png) (https://postimg.cc/xk3myVyc)

chan 2 pots n sockets

(https://i.postimg.cc/d7YdyVCb/chan-2-pots-n-sockets.png) (https://postimg.cc/d7YdyVCb)

fuzz and verb sockets

(https://i.postimg.cc/t7ShMy06/fuzz-reverb-socket.png) (https://postimg.cc/t7ShMy06)


mixer pins, from back, left to right

(https://i.postimg.cc/SJnW05qv/mixer-pins-detail.png) (https://postimg.cc/SJnW05qv)

terminal blocks and power supply

(https://i.postimg.cc/qNnyq3Nc/terminal-block-and-power-supply.png) (https://postimg.cc/qNnyq3Nc)


trem socket and more BOM stuff
(https://i.postimg.cc/1nRqv7JM/trem-sockets-bom.png) (https://postimg.cc/1nRqv7JM)

let me know if i missed anything, or if ya need more info rob, and i will try and find it!!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 11, 2019, 01:26:46 AM
Quote
ok, here we go bro... all the dirt~~
Wow ,full on dude, thanks.

I've only produced a humble output of a partially drawn-up Trem.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 11, 2019, 02:10:11 AM
here's a vero of the fuzztone itself, i added the usual power filtering stuff, and a couple ideas for mods. i'm curious to see what them extra pads on the fuzz are for. thinking a pot there may vary the tone a bit.
i haven't even breadboarded it yet, but the vero is good to the schematic and seems to match the board.

i'll probably give it a go tomorrow. i figured, may as well call it the ovation 69 pedal, cuz thats what it is lol

catch up tomorrow... have a great nite. @#$% me, its 2 am again already lol

musician hours


(https://i.postimg.cc/8JH98Rjk/Ovation-69-Fuzz-1.png) (https://postimg.cc/8JH98Rjk)

its gotta nice symetry to it.
i played thru the thing for a couple hours tonite, really digging the tones i can get out of the behemoth.
worlds bulkiest stompbox ;)

dunno how the fuzz will sound by itself, but boyyyyyyyyy-howdie, sure sounds good "in parallel" now.

may have to add the preamp to the equation. the whole thing is so freekin weird, you'd think i had come up with some of it. i mean, hanging the fuzz off the preamp volume control n shit? wth?

lol

when i look at some of them connections, i scratch my eyes out in abject wonder.
the owsley musta been GOOD.

;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 11, 2019, 12:39:36 PM
noticed two value discrepancies on the fuzz board on two resistors, have updated the vero accordingly.
input resistor is 3.3k, e-ground resistor q2 shows 15k, tho that seems high to me!


(https://i.postimg.cc/Q9XVbHS7/ovation-69-fuzz1-1.png) (https://postimg.cc/Q9XVbHS7)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 11, 2019, 10:00:25 PM
Oh great dudiest one, may I summon thee ...

I've been trying to update the Reverb, Tremolo and Mixer to match up with your new info.

I've got a few fixes and also some questions.
-------------------------------------------------
Trem

Trem Socket
   #6            key
   #2, #4, #8,    }   n/c
   #10, #12, #14   }


   #16   Trem Speed 3 (green)  ?
   #1   Trem Speed 2 & 1 (yellow) ?

Trem Switches
   Green wire to Intensity #3 (clockwise) ?

Trem part values  [See Q1 pic]
   Value of 800R looks wrong.
   no values for parts under caps  - see pic

(https://i.postimg.cc/HJTYXw5q/01-question-trem-missing-parts.png) (https://postimg.cc/HJTYXw5q)
-------------------------------------------------
Reverb

   Q1 has 18R on base?
   R11 10k - check value

Tank Input
   The Tank-In connections look off by one, is it:
   Tank In Tip to #11 ?
   Tank In Shield to #12 ?
   (or, maybe Tip/Shield reverse of this)
-------------------------------------------------
Mixer:

Values for R5 and R9
-------------------------------------------------
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 12, 2019, 03:15:38 AM
dude...
i'm gonna have to print that list out and get back to you. gonna be tough to get the mixer values, i already put it back together there, i gotta completely dissassemble it to get at the switch side of the board. mega pia ;)

the rest i will have to check, i'll print it out and trace, other than the mixer, the rest is easy

r5 red/red/orange when blown up and messed with a little
r9 brown/black/orange

i AM guessing here, looking at the pics. but fairly sure, judging from the way all the others look to me. if it looks dim to you, thats probably kinda what it looks like to me naturally. learned to kinda deal with it.

Oh great dudiest one, may I summon thee ...

I've been trying to update the Reverb, Tremolo and Mixer to match up with your new info.

I've got a few fixes and also some questions.
-------------------------------------------------
Trem

Trem Socket
   #6            key
   #2, #4, #8,    }   n/c
   #10, #12, #14}


N/C # 15,too

Quote
   #16   Trem Speed 3 (green)  ?
   #1   Trem Speed 2 & 1 (yellow) ?

Trem Switches
   Green wire to Intensity #3 (clockwise) ? 

no, green wire from trem switches goes to center/common on both chan 1 and 2 switch.
the other end goes to trem speed #3, not intensity. intensity only uses two pins of the pot,  intensity pin
1, black,  goes to socket #18, and socket #13, brown, goes to intensity #2.

i counted counter clockwise on the switches
1    6
2    5
3    4 and circled the pin, color of wire, and where each connected to. in the case of the two trem switches, the connections are as follows.

green wire, to pin 2 of channel 1 trem switch, and jumpered across to pin 5 of channel 2 trem switch.
white wire, to pin 3 of channel one trem switch, to trem socket #4
white wire to pin 4 of channel 2 trem switch, to trem socket #5.

Quote

Trem part values  [See Q1 pic]
   Value of 800R looks wrong.


gray/black/brown/silver, but i can check again in the morning.

Quote
   no values for parts under caps  - see pic

(https://i.postimg.cc/HJTYXw5q/01-question-trem-missing-parts.png) (https://postimg.cc/HJTYXw5q)


the resistor to the right bottom is 100k, i wrote it in, but its not quite lined up right cuz it was under the caps and i was trying to get a place with enough contrast to see it.

under the big caps on the bottom, no resistors there. just the caps and then the vactrols.

i will double check tomorrow to be sure, tho.

Quote
-------------------------------------------------
Reverb

   Q1 has 18R on base? 
   R11 10k - check value


i THINK it does. its a weird looking huge resistor with like, three bands and its gooped onto the transistor with some ancient taffy looking epoxy, so hard to see the exact value.

i will check the value in the morning for R11. pretty sure it was 10k, brown/black/orange


Quote
Tank Input
   The Tank-In connections look off by one, is it:
   Tank In Tip to #11 ?
   Tank In Shield to #12 ?
   (or, maybe Tip/Shield reverse of this)

reverb send from socket #10 to reverb tank in/hot/tip
reverb socket #11, shield from above.

reverb return from reverb tank output/hot/tip to reverb socket #6
reverb socket #1 to shield of above.

Quote



-------------------------------------------------
Mixer:

Values for R5 and R9
-------------------------------------------------


i believe those are 22k for R5 and 10k for R9.  those are the ones i can't get to, hesitant to take it apart again. it was a real bitch to get it back together, even after i figured out how to do it, it took a couple hours.

i will check tomorrow on everything else tho.

i DID build a veroboard version of the fuzztone section tonite, complete with bc109's. i built it with 100n caps instead of 1n cuz the 1n sounded really thin and shitty. everything else to the schematic and parts.

i mounted it right to the fuzz pot, see how it sounds tomorrow, and if it will need another volume pot at the end.

i have a feeling the thing to do is probably cascade the two channels together and then put the fuzz after that lol  :icon_twisted: :icon_twisted: :icon_twisted: :icon_twisted:

here's a couple pics
(https://i.postimg.cc/m1rj6gkt/vero1.jpg) (https://postimg.cc/m1rj6gkt)

(https://i.postimg.cc/gnQsNdW2/vero2.jpg) (https://postimg.cc/gnQsNdW2)

(https://i.postimg.cc/4Kb1f9hY/vero3.jpg) (https://postimg.cc/4Kb1f9hY)

i'll have eyegore put the electricity to it tomorrow and see if it boogies,or if it fails... i expect a little tweakage for max fuzzy goodness will be necessary ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 12, 2019, 06:07:40 PM
Quote
no, green wire from trem switches goes to center/common on both chan 1 and 2 switch.
the other end goes to trem speed #3, not intensity. intensity only uses two pins of the pot,  intensity pin
1, black,  goes to socket #18, and socket #13, brown, goes to intensity #2.
I can sort of see that in the photos you posted but when I go to the circuit the tremolo intensity and switching just doesn't make sense (to the point where I doubt it will work as drawn).  Some detail is missing.

Quote
reverb send from socket #10 to reverb tank in/hot/tip
reverb socket #11, shield from above.

reverb return from reverb tank output/hot/tip to reverb socket #6
reverb socket #1 to shield of above.

That's another one that doesn't make sense when I go to the schematic.
When I look at the pics of the reverb edge connector to me it looks like the tank wires to the last two terminals 11 and 12.  That also makes more sense from a schematic perspective.


Quote
the resistor to the right bottom is 100k, i wrote it in, but its not quite lined up right cuz it was under the caps and i was trying to get a place with enough contrast to see it
When I look at the photos I can see about three resistors unaccounted for (See XRAY pic in next post).   I believe, the one you mentioned *is* there, more or less in that spot.

Quote
i believe those are 22k for R5 and 10k for R9.  those are the ones i can't get to, hesitant to take it apart again. it was a real bitch to get it back together, even after i figured out how to do it, it took a couple hours.

i will check tomorrow on everything else tho.

Yes, I don't think you want to pull it apart again.    We will just have to take what we have as is.  If you or someone else wants to resolve any of the those areas in the future then it should be a relatively easy.


Quote
i DID build a veroboard version of the fuzztone section tonite, complete with bc109's. i built it with 100n caps instead of 1n cuz the 1n sounded really thin and shitty. everything else to the schematic and parts.
Looks cool.   You should of started another thread for the stand-along fuzz.



Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 12, 2019, 06:10:45 PM
I've update the revision to V2 to represent you numbering.

(https://i.postimg.cc/TKxzBpFc/Ovation-K6001-1ofx-Channel1-Board.png) (https://postimg.cc/TKxzBpFc)

(https://i.postimg.cc/BjCr3JGf/Ovation-K6001-2ofx-Channel2-Board.png) (https://postimg.cc/BjCr3JGf)

(https://i.postimg.cc/67jF7z3H/Ovation-K6001-3ofx-Fuzz-Board.png) (https://postimg.cc/67jF7z3H)

(https://i.postimg.cc/G86NK2vG/Ovation-K6001-4ofx-Reverb-Board.png) (https://postimg.cc/G86NK2vG)

(https://i.postimg.cc/qgCWRsdL/Ovation-K6001-5ofx-Tremolo-Board.png) (https://postimg.cc/qgCWRsdL)

(https://i.postimg.cc/3d5VDk8H/Ovation-K6001-7ofx-Mixer-Board.png) (https://postimg.cc/3d5VDk8H)


(https://i.postimg.cc/87w03wh1/Part-Designators-CH2was-CH1-Board-top-view-xray.png) (https://postimg.cc/87w03wh1)

(https://i.postimg.cc/y3qQ9GzT/Part-Designators-Fuzz-Board-top-view-xray.png) (https://postimg.cc/y3qQ9GzT)

(https://i.postimg.cc/gLvMKKzb/Part-Designators-Mixer-Board-top-view-xray.png) (https://postimg.cc/gLvMKKzb)

(https://i.postimg.cc/kBmYgLsJ/Part-Designators-Reverb-Board-top-view-xray.png) (https://postimg.cc/kBmYgLsJ)

(https://i.postimg.cc/Yv2X1gTT/Part-Designators-Trem-Board-top-view-xray.png) (https://postimg.cc/Yv2X1gTT)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 12, 2019, 06:25:27 PM
Quote
no, green wire from trem switches goes to center/common on both chan 1 and 2 switch.
the other end goes to trem speed #3, not intensity. intensity only uses two pins of the pot,  intensity pin
1, black,  goes to socket #18, and socket #13, brown, goes to intensity #2.
I can sort of see that in the photos you posted but when I go to the circuit the tremolo intensity and switching just doesn't make sense (to the point where I doubt it will work as drawn).  Some detail is missing.

remember, the tremolo gets shorted to ground by the footswitch. i'll have to look at my notes or the unit to see any more. but i not only eyeballed the stuff, i used my continuity beeper to be sure.

the trem is always on, unless the footswitch shorts it out. the switches appear to switch the channels feed to the trem off or on. reverb etc also appears to be the same kind of deal.


Quote
Quote
reverb send from socket #10 to reverb tank in/hot/tip
reverb socket #11, shield from above.

reverb return from reverb tank output/hot/tip to reverb socket #6
reverb socket #1 to shield of above.

That's another one that doesn't make sense when I go to the schematic.
When I look at the pics of the reverb edge connector to me it looks like the tank wires to the last two terminals 11 and 12.  That also makes more sense from a schematic perspective.

nope, what i wrote is how it is, i checked visually multiple times, and beeped it, too. thats the way it hooks up! it IS weird. one reverb wire comes right back to two adjacent terminals, the other one there's like 5 terminals between hot and shield.



Quote
Quote
the resistor to the right bottom is 100k, i wrote it in, but its not quite lined up right cuz it was under the caps and i was trying to get a place with enough contrast to see it
When I look at the photos I can see about three resistors unaccounted for (See XRAY pic in next post).   I believe, the one you mentioned *is* there, more or less in that spot.
i will check as soon as i go downstairs, but i've gone over it several times. there aren't any resistors there, if they were, they'd be in parallel with the big 470n caps along the bottom edge. if ya look at the trace side pics, you can see where the caps are, then the optos. but i WILL check again ASAP...


Quote
Quote
i believe those are 22k for R5 and 10k for R9.  those are the ones i can't get to, hesitant to take it apart again. it was a real bitch to get it back together, even after i figured out how to do it, it took a couple hours.

i will check tomorrow on everything else tho.

Yes, I don't think you want to pull it apart again.    We will just have to take what we have as is.  If you or someone else wants to resolve any of the those areas in the future then it should be a relatively easy.

well, they only used so many resistor values in the whole amp. it was a real bitch to see without daylight, but in daylight, anything that looks white to me at nite is actually yellow. so i am sure the one is 100k, the other, i can see a hint of colors so pretty sure its right. if not... oooops. should be easy enough to sort out in the future, as you said!


Quote
Quote
i DID build a veroboard version of the fuzztone section tonite, complete with bc109's. i built it with 100n caps instead of 1n cuz the 1n sounded really thin and shitty. everything else to the schematic and parts.
Looks cool.   You should of started another thread for the stand-along fuzz.
[/quote]
we'll get there. first i wanna try it and see if its worth messing with. fairly sure it may need some value changes or part additions. channel 2 knobs have an effect on it, but its weird cuz it taps off to the fuzz off the volume if i remember right.

been busy all day dealing with baloney.... gonna go hit the dungeon, will report back shortly. peace!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 12, 2019, 07:40:46 PM
Quote
remember, the tremolo gets shorted to ground by the footswitch. i'll have to look at my notes or the unit to see any more. but i not only eyeballed the stuff, i used my continuity beeper to be sure.

the trem is always on, unless the footswitch shorts it out. the switches appear to switch the channels feed to the trem off or on. reverb etc also appears to be the same kind of deal.
It's coming unstuck for me because:
- The front panel switch have to be able to work individually.  So you can't kill the oscillator with the switches because that would kill both channels.  The footswitch could kill the oscillator.
- You would expect the intensity control to affect the LFO output level.   If the Intensity pot went to the two inputs of the two transistors that drive the Vactrols that would makes sense.
- I can't see where the common wire on trem front panel switches goes.    Does it go to ground?

When I look at the circuit I see it has the circuit blocks to work but when I try to match that up with wiring it goes haywire.

Quote
nope, what i wrote is how it is, i checked visually multiple times, and beeped it, too. thats the way it hooks up! it IS weird. one reverb wire comes right back to two adjacent terminals, the other one there's like 5 terminals between hot and shield.
It's very puzzling to have the Reverb Tank input going back to the input.  If it was an inverting amplifier that would make sense but only if the input circuit was low impedance, which it's not.   As is I can't see how the Tank is going to get enough drive.

Quote
there aren't any resistors there, if they were, they'd be in parallel with the big 470n caps along the bottom edge.
When I check the PCB traces it really looks like they are in series.  ;D ;D ;D ;D

There's a whole lot of things that don't add up.   I've tried to twist things around in my head but I just can't make sense if it.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 12, 2019, 10:19:55 PM
Quote
remember, the tremolo gets shorted to ground by the footswitch. i'll have to look at my notes or the unit to see any more. but i not only eyeballed the stuff, i used my continuity beeper to be sure.

the trem is always on, unless the footswitch shorts it out. the switches appear to switch the channels feed to the trem off or on. reverb etc also appears to be the same kind of deal.
It's coming unstuck for me because:
- The front panel switch have to be able to work individually.  So you can't kill the oscillator with the switches because that would kill both channels.  The footswitch could kill the oscillator.
- You would expect the intensity control to affect the LFO output level.   If the Intensity pot went to the two inputs of the two transistors that drive the Vactrols that would makes sense.
- I can't see where the common wire on trem front panel switches goes.    Does it go to ground?

trem socket , key in #4 left/right from component side, pin 1, yellow wire, goes to speed pot 1 & 2. pin 3 of the speed pot is what goes to the common on the two tremolo on/off switches. each tremolo switch then goes back via its own white wire to its own input on the tremolo socket. the channel one switch return wire goes to tremolo socket #4, the channel 2 switch return wire goes to tremolo socket #5. both wires white. so i guess it completes the circuit when connected. i don't understand it enough to be able to really figure it out.
but i DO have some news to blow your mind that may explain some stuff making no sense at all.


Quote
When I look at the circuit I see it has the circuit blocks to work but when I try to match that up with wiring it goes haywire.

probably cuz it all seems to be in parallel in really weird @#$%ing ways. it was designed to be "bulletproof" and not go down. so its weird. but all the numbers are matching up from here between different points so far. i know its mind bogglingly weird and hard, and ALIEN.


Quote
Quote
nope, what i wrote is how it is, i checked visually multiple times, and beeped it, too. thats the way it hooks up! it IS weird. one reverb wire comes right back to two adjacent terminals, the other one there's like 5 terminals between hot and shield.
It's very puzzling to have the Reverb Tank input going back to the input.  If it was an inverting amplifier that would make sense but only if the input circuit was low impedance, which it's not.   As is I can't see how the Tank is going to get enough drive.

man, the reverb has TONNES of drive, actually... it can overdrive it even. the reverb tank input goes to the reverb tank send, the output of the reverb first stage, then comes back to it from the reverb out of the tank to the reverb return of the amp. unless ya mean how it hooks up to the circuit itself, no idea... but... in a minute, get ready to cue up some mother@#$%in rick and morty shit, bro, morty's mindblowers kinda shit....


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Quote
there aren't any resistors there, if they were, they'd be in parallel with the big 470n caps along the bottom edge.
When I check the PCB traces it really looks like they are in series.  ;D ;D ;D ;D

hahah, they may be, i AM an idiot, and cuzza the snow and my girls paranoia about having to remove it before it hits the ground so she can get out in the morning <g> i haven't had a chance to check yet, i was debugging the fuzz i built off this schematic last nite. i made a rookie vero mistake and had to change the location of the output wire, and then i fired it up.

man, sounds like SHIT. absotively @#$%ing horribler than the most horrible. lucifer dave would love it. so broken, so jagged, so 60's...  but it passed signal, runs on 9volts.

it wants REAL low gain q in #1. q1 IS an npn, and it wants a gain of about 100... bc109b would work. the bc109's i have are like WAYYYYYY too hot.  i ended up going with an old button npn, marked c891 340.
my meter says hFE 105, Uf 737mv
battery slightly low, 8.49v
voltages
C 7.32v
B   .40
E    0

q2 is where shit gets weird. the only way i could get it to kinda bias up and get a semi useable fuzztone with a reasonable amount of output was to use a bc549,
hFE 432, Uf683mv..... but according to my meter, REVERSE beta'd. only way it would fire.
voltages were good
C 4.68
B  .56
E  .5 (or 0 with the 1.5k resistor shorted)

i was like...wtf? checked the pinout, checked the meters...

then had an epiphany. epiphone?

dude, i think q2 may not be a bc109, it may be a bc something, but its gooped under some kind of nasty hard epoxy.  i believe that q2 is PNP, not NPN.

i dunno if that explains anything... but then, every @#$%ing pnp i thru at it, si or ge with the beta right way according to both my meters, fired right up and actually sounded GOOD.
didn't care what it was i thru in there.
but either reverse beta npn, or pnp... to my simple hippy mind, it makes sense it may be supposed to be pnp?
what do you think?
perhaps some of the other shit is like that too? :o :o :o :o :o


Quote
Quote
There's a whole lot of things that don't add up.   I've tried to twist things around in my head but I just can't make sense if it.

dude, it was 1969, and the owsleys were flowing, so no surprise its kinda.... ummm..."creative".

anyways,. when i get back from the endless snow drudge, i will check the tremolo board and report back. still messing with the fuzz circuit, but once ya pop a pnp in q2, it becomes much more forgiving of which transistors work.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 13, 2019, 12:31:27 AM
rob,
looking at your schematic, i realized we were looking at the socket #'s for the reverb opposite.. we numbered them differently.

i took some time to try and figure it out, it looks like at some point, the numbering got reversed, BUT on top of that, a couple PINS got reversed, too...

so i compared notes to notes to drawings, and this is what i came up with. most of the pins simply needed the numbers reversed, which @#$%s EVERYthing up, as pin 7 becomes pin 6 etc...

so anyways, most of it was backwards, and a couple were backwards from THAT so were actually RIGHT.  :o

anyways... try this one on and see if it will make better sense.


i can't speak for the circuit, as i still don't follow all things non fuzzy very well, but the pinouts should now match up as well as the color coding, i cross ref'd both with each other til some sense arose out of the din. i think. ;)


aww fudge, just found a mega mistake... bear with me..
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 13, 2019, 01:58:56 AM
ok, try this for the reverb. all the wires seem to match up now. none of the numbers did between us tho. i numbered all the connections as per MY notes, and all the stuff lines up that way. i know it doesn't make a whole lot of sense, from my notes, but i think now it should work ok hopefully.

you were going off my original flawed data, and i bet thats what @#$%ed us all up. i believe now this should work... the send goes to the tank in, the return comes back, what looks like the input goes to the terminal block and then the footswitch to turn the whole mess on and off. power comes in from the terminal block on the orange wire to pin 9.  i can't make sense of it completely without including the switches on the mixer, but i think that should be easy enough to figure out from the wiring notes and the pics of it. but it looks to me like something from the switches on the terminal block turn the reverb off and on before the input. i am probably wrong, gotta take a good hard look at the mixer.

ok, just did. the mixer was labeled backwards too. here's a fix, that seems to match all my notes.

reverb first

(https://i.postimg.cc/LY5pp5Fr/verb-correct-maybe.png) (https://postimg.cc/LY5pp5Fr)

here's the mixer


(https://i.postimg.cc/VSSgPPHK/mixer-corrected-maybe.png) (https://postimg.cc/VSSgPPHK)

i will try and match up the other parts too, maybe tomorrow or something. should be able to do the same for the fuzz, and the tremolo which i finally will check for "hidden" resistors so we can drag them out into the light and punish them for #resisting ;)

but please check the two graphics out, and see what ya think. maybe now some of this shit will start making sense. i doubt it, but, hey... ya never know!! ;)
thanks for all the help bro. i'm learning a shit-tonne, and i think we're gonna get it right. ;)

so many pins, so many wires, its like a bloody hammond organism ffs!
easy to get stuff backwards/confused etc. but i think we're getting on top of it!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: bluebunny on February 13, 2019, 02:49:02 AM
I am stuffed to the gills on popcorn.    :icon_eek:    :icon_cool:
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 13, 2019, 03:18:09 AM
one verified schematic for the resurrected 1969 ovation 6000 series preamp fuzztone coming atcha's jus' bout 'soon as i can scan's, it hoss, oh hell's yes.
and the mofo REQUIRES

LOW GAIN GERMANIUM!!!!!

or else it sounds like poo! one knob! ya can mount the vero to the knob.. or will be able to, once i re-jig the vero.

schematic coming... don't put that popcorn away yet!!
lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 13, 2019, 03:39:42 AM
ok me fuzzy friends n droogies, here ya go, a shot o' the ol' molokko straight from 1969ish

have at it and have fun. low gain ge is the way to GO! 30, 40 hfe will work. above 100ish it starts to sound shitty and badly biased, i'm betting it was designed for germanium transistors, and they just switched to si when they "improved" it. a lot of engineers were either high on lsd or thought screw it, they want some distortion, lets give them some and make it extra @#$%ing shitty. i tried an ass load of transistors in the circuit, gains ranging from 20 to 560 in both npn and pnp. keep it under 100.
ge sounded best. much to my surprise, q2 has gotta be PNP! so its a pnp/npn dealio. or should be.
i bet they made a mistake when it went into production and they really figured screw it, it sounds horrible, the kids will love it. there's two bc109s stuffed in the factory board, but i bet they @#$%ed up and stuffed a pair of npns at some point, not knowing the difference maybe, cuz the fuzz was never spectacular on any of the units i played.
any pnp in q2 makes it instantly sound better. interestingly, a reverse biased bc549 in q2 actually sounds good and has fair volume! BUT the volume doesn't operate smoothly.. its all or nothing. just like on the original unit. so they definitely @#$%ed it up at some point and either never cared, or never noticed.... whichis a shame, cuz the whole package, when done right, would have been completely @#$%in mind blowing.
i DID add 100n caps to the original fuzz board. i AM gonna swap out the shitty bc109's <and save 'em for something they'll sound GOOD in> and put in the ge combo mentioned as i have a few of each kicking around.  that will bring the old preamp into the 21st century and make it actually useable.
i ordered parts for the footswitching, too, so when thats done, its gonna have footswitchable reverb, trem, and fuzz.  it'll even have led's, cuz i got 2 extra wires i can use to power them separate from the audio function of the other 4 wires already being used out of the 6 pins of the din plug.

that was a mouthful. yikes.

anyways, here ya go... DIY OR DIE, YE SCURVY MONGRELS!! GIVE ME AND MUNKY AND ROB SOME CREDIT WHEN YA RIP THIS OFF LMAO

I  present to you, The Fuzz Ovation


(https://i.postimg.cc/ZCYTmp1D/the-fuzz-ovation.png) (https://postimg.cc/ZCYTmp1D)

breadboard it NOW
antd
bee leef me lator

but i think its a keeper. rock on!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 13, 2019, 04:00:51 AM
updated vero, you can mount the 50-100k pot right to the board if you like the way its layed out. yeah, shoulda centered it, but... its 4 am, i'm a friend of bob's, and if you wanna send me 29.95 in unmarked 2 dollar bills, i'll tell ya all about why you should cut me some slack. ;)

have fun, make loud scary noises!


(https://i.postimg.cc/4Knvkygh/The-Fuzz-Ovation-1-1verified-vero.png) (https://postimg.cc/4Knvkygh)

and with that, GOOD NITE, IRENE, WHEREVER YOU ARE
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 13, 2019, 04:07:35 AM
duh!!!

ROB.... them two mystery resistors my dumb@#$% ass didn't notice under the two big caps are both 1.5k. ;)

 :icon_redface:

hahaha  :icon_mrgreen:
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 13, 2019, 04:14:57 PM
Quote
reverb first
Ah, that messed with my head then I realized the problem.   You updated the edge-connector numbers on the PCB side so the circuit makes sense when the connected to the outside world.   However, the parts on the PCB *have* to go to the edge connector numbers shown on the schematic because that is how the PCB is wired .  Changing the numbers only is like re-wiring the PCB.   The only thing we are allowed to change is the ordering left/right or right/left numbering on the PCB.    However, the numbering on the V2 reverb schematic matches your wiring list.     So that's the problem I've been struggling with try to match-up the external wiring so the circuit makes sense.  Ahhh.

Quote
ok, just did. the mixer was labeled backwards too. here's a fix, that seems to match all my notes.

here's the mixer
OK.  This makes sense.  You actually update the numbers on the (old) V1.0 schematic.  The last dump of V2.0 schematics pretty much gathers up all those new numbers and matches what you have done.    When I look at the solder bridge on the pics it looks like it goes to a ground track.  There's a couple other of things you updated I'll transfer across.

Quote
ROB.... them two mystery resistors my dumb@#$% ass didn't notice under the two big caps are both 1.5k.
OK cool.  What about the third resistor?

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 13, 2019, 04:19:15 PM
Quote
I  present to you, The Fuzz Ovation

Cool, interesting it needs a germanium.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 13, 2019, 05:20:43 PM
the third resistor, under the caps on the right side of the component face of the board is 100k.

yeah, germanium. its a great sounding fuzz with germanium, and the npn/pnp combo.  with the two bc109's it sounded just as shitty as the original.

in the preamp headpiece, ya can kinda get away with it cuz its parallel, its adding fuzz along with the clean signal. but its a really wretched sound.

with the ge and bigger caps, it sounds a lot better. even better, into the ovation preamp and fuzzing it with the onboard fuzz, which makes me suspect a 4 knob variant may be really hip!

glad we sorted out the wiring deets etc.. now hopefully it will make sense.

look forward to your thoughts!

i am waiting for fedex to arrive so i can wire up the footswitch stuff, then i think i can close her up and finally get her off my bench and do some work.

the vero will just fit a 1590a if you're slick. i will try and get video over the next couple days, hopefully the last time i took this pos comp apart, i fixed the echoechoechoechec... problem
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 14, 2019, 01:16:33 AM
started wiring up the footswitch tonite and messing with a few things. i auditioned a couple transistors in the amp, including by mistake swapping the pnp and npn positions, which surprisingly still worked. crazy.
ended up with the q1 from the pedal version, and q2, after trying a bunch of si and ge and gains, went with a trusty old 3906, which works great in there. now its gotta bit of boost.. q1 ge npn about 65hfe, q2 si pnp about 389hfe. seems to work well.

in the standalone version, shoot for like, 60hfe.

anyways, with the 3906 and ge in there, it gotta bit of a boost, and the tremolo is no longer so weak.. and it fades in almost like a kustom kinda "vibe/tremolo" feeling as the notes decay. pretty hip.

black wire to the footswitch is common, short the blue green or fuzz to ground and off they go.
gotta look at the connections of them top boosts. see how they connect to the circuit.
channel one has some balls now, and if ya run into the #2 input on it with your guitar, and use a jumper to #2 channel input #2, you can use channel one to overdrive channel two, and then use channel two to drive the fuzz... in parallel. the combo of the parallel fuzz and two channels is real similar to an early marshall sound, which makes me wonder if the transistors maybe are fets in the preamps? they don't seem too harsh when clipped hard.
can get some just absolutely sick sounds out of it. i wanna do a demo, but there's so much ya can do with it.

and the standalone fuzz version into it really sounds good.  i think i may make another one with two cascaded and see what happens.  or maybe just an extra gain stage.  who knows. i shoulda been in bed like, days ago it seems like. chronic insomnia sucks. lol.

but gives ya a lot of time to mess with stuff, tinker with things, and let the magick smoke out.

peaaaaaaaaaaaace
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 14, 2019, 06:48:12 PM
Schematic release V2.1

OK. This is about as far as I can go based on the comments you made and what I can see on the boards.
The schematics as good as I can make them from the board perspective.
How the wiring meets up with the boards follows your comments and the "big wiring lists".


(https://i.postimg.cc/jwYF3j0m/Ovation-K6001-1ofx-Channel1-Board.png) (https://postimg.cc/jwYF3j0m)

(https://i.postimg.cc/TyV9wqFN/Ovation-K6001-2ofx-Channel2-Board.png) (https://postimg.cc/TyV9wqFN)

(https://i.postimg.cc/474z3Czn/Ovation-K6001-3ofx-Fuzz-Board.png) (https://postimg.cc/474z3Czn)

(https://i.postimg.cc/w3vX8pqG/Ovation-K6001-4ofx-Reverb-Board.png) (https://postimg.cc/w3vX8pqG)

(https://i.postimg.cc/HrGXy8Qq/Ovation-K6001-5ofx-Tremolo-Board.png) (https://postimg.cc/HrGXy8Qq)

(https://i.postimg.cc/cvQYM1hr/Ovation-K6001-7ofx-Mixer-Board.png) (https://postimg.cc/cvQYM1hr)
-------------------------------------------------------------------------
Summary
Updates schematics V2.0 to V2.1
15 Feb 2019
-------------------------------------------------------------------------
2) Channel 1 - Sheet 1

updated rev to 2.1 only to match other sheets
-------------------------------------------------------------------------
2) Channel 2 - Sheet 2

2.1) Fixed pin numbers for Fuzz connections
Reversed numbering error.

2.2) Note:  R22 on channel 2 is 47k (see pics)
-------------------------------------------------------------------------
3) Fuzz - Sheet 3

3.1)

Reply #129 on: February 11, 2019, 12:39:36 PM

Noticed two value discrepancies on the fuzz board on two resistors,
have updated the vero accordingly.

input resistor is 3.3k,
e-ground resistor q2 shows 15k, tho that seems high to me!

Should be
33k, and
1k5 or 15k?

3.2) Wiring List Error  [*** Wiring not schematic]

4 to 8  has off by 1 bug
Should be,
4   NC
move 4 thru 7 to 5 thru 8

3.3) Updates fuzz input & output connection text
Ch2 #7 to Fuzz #2 (blue)
Ch2 #17 to Fuzz #11 (yellow)
-------------------------------------------------------------------------
4) Reverb - Sheet 4

4.1) Checked edge connector numbers against circuit components.

4.2) Check edge connector numbers against wiring list
(Reply #126 on: February 10, 2019, 10:49:29 PM)
-------------------------------------------------------------------------
5) Trem - Sheet 5

5.1) Missing Resistors
   Near opto's   2x 1.5k
   LFO output   1x 100k

gray/black/brown/silver, but i can check again in the morning.

5.2) R5 (800R)
Reply #131 on: February 12, 2019, 03:15:38 AM
gray/black/brown/silver, but i can check again in the morning.

5.3) Trem Switches
Reply #131 on: February 12, 2019, 03:15:38 AM

green wire from trem switches goes to center/common on both chan 1 and 2 switch.
the other end goes to trem speed #3, not intensity.
intensity only uses two pins of the pot, 
intensity pin 1, black,  goes to socket #18,
and socket #13, brown, goes to intensity #2.

green wire, to pin 2 of channel 1 trem switch,
and jumpered across to pin 5 of channel 2 trem switch.
white wire, to pin 3 of channel one trem switch, to trem socket #4  [Rob: Actually #9 from wiring]
white wire to pin 4 of channel 2 trem switch, to trem socket #5.
-------------------------------------------------------------------------
7) Mixer - Sheet 7

7.1) Resistor Values

Reply #131 on: February 12, 2019, 03:15:38 AM

r5 red/red/orange when blown up and messed with a little
   =22k

r9 brown/black/orange
   =10k

[Rob: Based on one pic I can seed the last band is actually red.
 In the unmodifier form the circuit is the same as the reverb which uses 1.5k]

7.2) Connections
Marked-up *V1.0* drawing 2/3/19
V2.0 matches except for Mixer #4 to Reverb #3.
However wiring list shows Miixer #3 to Reverb #10.
[#3 is reversed numbered #10, #10 is correct]
-------------------------------------------------------------------------
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 14, 2019, 06:49:36 PM
Quote
but gives ya a lot of time to mess with stuff, tinker with things, and let the magick smoke out.

The older the smoke the harder it is to put back in  ;D
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 14, 2019, 07:13:12 PM
holy cow. dude, you are amazing!!
i am on my way out the door for my thursday gig, but a couple things...

the reverb shield is weird. i will look at it AGAIN, but i know the outcome.

the send/tip/hot of the reverb tank connects to reverb socket #10, it is a normal shielded wire center conductor, not bl or black as on the new schematic.

the shield of the same wire connects to pin #11... remember, this is all numbered as ya look at it left to right, in this case left to right is with the components facing you rather than the trace side cuzza the way they made the unit. very weird.

the fuzz e to ground resistor is 1.5k, 15 is way too high.
i tried 3.3k and 33k on the input of the fuzz, made almost no difference whatsoever.

shit. i gotta look at this when i get home... check in later, 2 am-ish ;)

herculean task, there, bud!!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 14, 2019, 07:17:26 PM
ya know what? belay all that til i can look again. i think we're getting some pins confused. the footswitch wire for the reverb shorts to ground... blue wire you have going to the input of the tank, but thats actually not pin 3, which is blue.  when ya short the reverb to ground, it kills the output of the reverb, or you'd hear the splash of verb continue when ya hit the footswitch.

i DID get that far last nite, i wired up the 6 pin din, was waiting for another dpdt to show up today and finish it.

all the footswitchable effects are normally open. when ya shunt them to ground, it turns them off. reverb,  fuzz, and trem.

we're close. just gotta sort out a couple details, but i see a few thing under cursory exam that will need to be addressed... stay tuned!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 14, 2019, 08:47:26 PM
Quote
herculean task, there, bud!!
I think we have both been working overtime on this one.
It's a bit quirky and messes with you head.


Quote
ya know what? belay all that til i can look again. i think we're getting some pins confused. the footswitch wire for the reverb shorts to ground... blue wire you have going to the input of the tank, but thats actually not pin 3, which is blue.  when ya short the reverb to ground, it kills the output of the reverb, or you'd hear the splash of verb continue when ya hit the footswitch.

OK there' might be a problem there.    The details of how the footswitch works is a mystery to me.   When I looked at the schematic, there is a Blue wire on reverb pin #3 and a Blue wiire on reverb pin #10.
The reverb pin #10 connection goes to the mixer and that does make 100% sense to me.   The reverb pin #3 is the weird one.  I assumed that went to the footswitch and somehow pulled the rug from under it by killing the power to the reverb.   The biasing on Q3 (R12, R13) looks ODD and I assumed this was to stop it banging when the power was cycled.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 15, 2019, 06:48:21 PM
Quote
herculean task, there, bud!!
I think we have both been working overtime on this one.
It's a bit quirky and messes with you head.


Quote
ya know what? belay all that til i can look again. i think we're getting some pins confused. the footswitch wire for the reverb shorts to ground... blue wire you have going to the input of the tank, but thats actually not pin 3, which is blue.  when ya short the reverb to ground, it kills the output of the reverb, or you'd hear the splash of verb continue when ya hit the footswitch.

OK there' might be a problem there.    The details of how the footswitch works is a mystery to me.   When I looked at the schematic, there is a Blue wire on reverb pin #3 and a Blue wiire on reverb pin #10.
The reverb pin #10 connection goes to the mixer and that does make 100% sense to me.   The reverb pin #3 is the weird one.  I assumed that went to the footswitch and somehow pulled the rug from under it by killing the power to the reverb.   The biasing on Q3 (R12, R13) looks ODD and I assumed this was to stop it banging when the power was cycled.

yeah, no, there is NO blue wire to pin 10, never was. that's a mistaken holdover from when i first wrote stuff down and numbered the sockets opposite from how you did.

socket #10 becomes socket #3, see? socket 10 however has the hot from the reverb tank input going to it. and the shield to #11. i suspect at some poiint in my notes before i figured out what i was doing i confused reverb input and output wires.

it would appear that the input of the reverb drive amp would be from the preamp or mixer, but the output of the reverb tank can't possibly work as the schematic is showing now on the updated version

(https://postimg.cc/w3vX8pqG)

r 11 looks too low, but its connecting to the shield going back to the reverb tank, "floating" it above ground. near the reverb return/reverb output jack on the tank itself, the tank is grounded to the chassis for the ground connection there.

tank in TIP is to # 10.  the shield is to #11. that is for the reverb drive amp. i suspect you've got whats labeled #10, 9 and 11 mixed up. to me, it looks like what you have as pin #9 on the last schematic is actually pin 11. as shown, in the most recent schematic, pin 11 would be the +, with the 680r resistor being last in line before the tank input.

so... by the most recent schematic, as shown,

pin 10 is actually pin 3, blue wire going to the reverb footswitch

pin 9 is actually pin 11, reverb tank send shield

pin 11 is actually pin 10, the reverb tank send tip/hot

at least those three connections are messed up
pin 12 is the black wire that goes back to the mixer ground. its at the mixer the reverb is either shorted out of the system or alive by the reverb switches themselves... the reverb on/off switches i would suspect feed the reverb input which comes off the reverb level pot.
the reverb footswitch simply shorts the mess to ground <blue wire, socket #3, not #10. #10 and 11 have shieled wire to them for the reverb send amp, hot pin 10, shield pin 11, no connection to pin 12, and the reverb return amp hot/tip is pin 6, with the shield connected to socket pin 1.

again, all this agrees with all the notes, so i think things just got confused there.
more in a bit. gotta digest things slowly.

i just checked over the schem again, and compared it to the notes. the above is accurate.

what i wrote, i mean.

pin 9, 10, and 11 as shown on the schematic are wrong.

pin 9 on schematic is shown as ... man this shit is confusing.  lol....

bear with me, working up the graphic

ok... i just compared notes and double checked everything. this is how the reverb hooks up. the input of the reverb tank as well as the REVERB CIRCUIT itself jumpers from mix pin#4, blue wire!

the reverb circuit itself is shunted to ground with the footswitch via reverb socket #3

B+ enters thru socket #9, orange wire coming from the terminal block on the power supply side, side a.

the reverb drive amp shield looks funny hanging off the 680r resistor, but again, thats to "float" it i think, the ultimate ground connection is made off the reverb tank itself to the chassis ground.


(https://i.postimg.cc/HcJFH1XB/Ovation-K6001-4ofx-Reverb-Board-corrected-pjp-2-15-19.png) (https://postimg.cc/HcJFH1XB)

check it over. this should now be correct. i will go thru the other boards, one at a time, to match up the schematics and the notes til we got the whole mess.

in some cases, shit gets even SCREWIER cuz there's multiple connections to things which aren't always shown with all the boards separate, but actually connect all the shit. we're used to series signal chains dealing with this, but this is all parallel. so... its gonna be super @#$%in weird bro!!

anyways.. check this, tell me if ya think it looks good, if so, the reverb is done, as is the fuzz i guess. little closer to nirvana!!! ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 15, 2019, 08:19:40 PM
(https://media.giphy.com/media/soEYm1YwpftVC/giphy.gif)

Quote
pin 9 on schematic is shown as ... man this shit is confusing.  lol....

bear with me, working up the graphic

I didn't get any of that!  I read all the words but I don't know what they mean  :icon_mrgreen:.

Quote
so... by the most recent schematic, as shown,

pin 10 is actually pin 3, blue wire going to the reverb footswitch

pin 9 is actually pin 11, reverb tank send shield

pin 11 is actually pin 10, the reverb tank send tip/hot

...
pin 9, 10, and 11 as shown on the schematic are wrong.
I'm not sure what is wrong.  For example,

Quote
pin 9 is actually pin 11, reverb tank send shield
Do you mean change where it says 9 on the schematic to an 11?

That's the *only* thing I can't do.  On the PCB (and the schematic)  pin 11 is connects to R8 and pin 9 connects to R4, R6, R13, and Q2's emitter.    You can see the tracks on the board and I've check it quite a number of times.

(https://i.postimg.cc/NyZzy8Q3/Reverb-Pin-9.png) (https://postimg.cc/NyZzy8Q3)

What can be changed is the color of the wires on pin 9 and the external connection.    So pin 9 is currently Orange and connects to Terminal Block A pin 5.     

Quote
bear with me, working up the graphic
So when I put the updates next to the V2.1 schematic it's pretty much the same connections to me.
However, if the circled numbers means I have to change only the Reverb pin numbers then we are screwed because those numbers have to go to the parts shown on the schematic.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 15, 2019, 08:50:36 PM
all the circled numbers on the schematic have been traced, beeped, verified and corrected for which pins they actually go to. its possible i have the pnp's connections backwards, as i'm not sure if the emitter is actually the reverb drive or the ground.  that part i had to guess. if it makes sense switching ONLY those two connections, thats hip, cuz one of the two terminates in the chassis ground off the tank itself, carried there in the shield of the cable.

i went over the trem socket wiring repeatedly, realized i made a couple mistakes earlier... see?
it IS me!! ;)

gonna post the graphic ,
but trem speed pot

#1 and 2 go to trem socket #1, yellow wire
#3 goes to trem socket #16, green wire

trem intensity i had afu

#1 goes to socket #18, black wire
#2 goes to socket #13, brown wire
#3 goes to trem switch common.
so i think the connection you're unsure of, is probably def not right.

the trem switches, going counter clockwise 1-6
green common  goes to trem sw 2 #5, and trem switch 1 #2, AND
goes to green wire to TB1, A1 as well.
trem switch 2 # 4, to trem sock #9
trem switch 1 #3 to trem sock #5

i did what i could for corrections on this one
check it and let me know. the connections all agree with the unit and my notes now


(https://i.postimg.cc/phrt0Xxd/Ovation-K6001-5ofx-Tremolo-Board-2-15-19-corrected-maybe.png) (https://postimg.cc/phrt0Xxd)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 15, 2019, 09:01:51 PM
hey rob,
dumbish question, but... if i disabled r 1 and 2 on the mixer, would that mean it when

duh. dumb question i didn't think thru ;)

do ya think there's a way to kill the reverb from the footswitch, but change it from the output of the verb to the input?
maybe switch the footswitch from killing the output of the verb, to shorting the input to ground instead? or is that gonna be POP!! causing issues with noise and stuff?

just curious. its 2019, be nice to let the verb "splash " when ya kill it. ;)

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 16, 2019, 01:42:41 AM
i had to ditch the 3906. playing with it today, it just plain sounded lousy. yeah, it was a little louder, but really just too farty and gross. so i replaced that mofo with the ac125 i first tried in the pedal...
yeah...

thats the ticket. woo hoo!

not real loud, but instantly sweet, like just-browning fender kinda tones.
no brainer. ge was most definitely what they were supposed to use, i'd say.
probably switched to si cuz it was NEW and IMPROVED and DID THE SAME THING BETTER!

egad. yeah, right.

ok. also finished the footswitch. i smoked one of 'em. haven't done that in years!
i tapped the power off the orange wire connection in the power supply, right off one of the 100uF cans itself. was reading 16v, i figured that would work! i didn't wanna take it later where it splits off to the preamps, i was concerned with led polution of the audio.

good thing i was. cuz man, it was NOT QUIET. it worked, but it needed some creative thinking.

so basically, its wired almost backwards from a stompbox. you HAVE to keep the AUDIO and LED grounds SEPARATE.

what i did was ground all the audio to the case with the black wire from the cable i got , and run all the "grounds" for the led's to the shield. the black wires in the amp also connect like that, and not to the shield, which makes me suspect that they "telescoped" the ground to the footswitches for this unit... hots and a cold, but shield connected at one end only.
anyways, that way, the noise from the led's gets nuked and no hash creeping into the audio.. and no more loud BRUZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ when the fuzz is turned on.
had to add pulldowns, went with 4.7m to case ground cuz they were convenient.
between separating the grounds and the big freekin resistors, most of the noise and pops are gone. when ya kick in the fuzz, it just sounds like ya went from a nice solid state to a nice brown tube instead of hideous noise and farty fuzztone. its hip.
dpdt's needed. each side is different, easier to look at the diagram i made than to explain it.

works great. with the ge in the fuzz, cranked full, ya can kick it on and its a very sweet overdrive now, the reverb works well, tho i'd rather kill the inputs than the outputs, and the trem is actually hip and kinda vibey... when the fuzz is on, it kinda fades in on stuff, with the fuzz off its just nice and shimmery, but not super deep. the reverb is hip! and if ya use the patching i reccomend into the inputs, it sounds like you're running a fender reverb into a tube amp input. its cool as hell.

i am babbling. been working all freekin day lol...
anyways,. here's pics

messy inside, recycled amp footswitch, had to drill some holes and mess with wiring some to get it working right, so a bit ugly, but functional. i just tied the three resistors together and soldered the white wire i added to the center pin of the plug for powering the whole mess.

(https://i.postimg.cc/PLZGrmws/o1.png) (https://postimg.cc/PLZGrmws)

(https://i.postimg.cc/SJtH6ZLb/O2.jpg) (https://postimg.cc/SJtH6ZLb)

(https://i.postimg.cc/CR3ttz6v/O3.jpg) (https://postimg.cc/CR3ttz6v)

here's a Q&D footswitch schematic

(https://i.postimg.cc/8s425kj5/OVATION-6000-FOOTSWITCH.png) (https://postimg.cc/8s425kj5)


i'm beginning to realize we're gonna have to get the power supply right, too, unless ya wanna just say screw it and let peeps use whatever they want. for posterity sake, and any poor loser who dare tread here trying to fix one, it would be kind of us to do i guess. pretty lazy tho.

gotta went. i need me some freekin breakfast! lol been a longggggggg day
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 16, 2019, 04:31:29 PM
For the Reverb:
Quote
all the circled numbers on the schematic have been traced, beeped, verified and corrected for which pins they actually go to. its possible i have the pnp's connections backwards, as i'm not sure if the emitter is actually the reverb drive or the ground.  that part i had to guess. if it makes sense switching ONLY those two connections, thats hip, cuz one of the two terminates in the chassis ground off the tank itself, carried there in the shield of the cable.
Hmmm, so really, that leaves up with the reverb connections unresolved/whacky.   Have you confirmed the reverb tank is internally grounded?  It's not a normal thing to do and even less normal for the drive side to be grounded even more so the tip - totally bizarre!   The PNP pin-out looks fine from the transistor data, the PCB and the way it is wired in the circuit.

Quote
just curious. its 2019, be nice to let the verb "splash " when ya kill it.
Cutting the tank input line might do that since there is DC through the input coil (from what I can see).
Normally you wouldn't want that though.

Quote
do ya think there's a way to kill the reverb from the footswitch, but change it from the output of the verb to the input?
maybe switch the footswitch from killing the output of the verb, to shorting the input to ground instead? or is that gonna be POP!! causing issues with noise and stuff?
There's many ways to do it.   Some methods may invoke the evil hum spirit, either due to the length of the wiring or where the grounding point are made (or due to restriction in the way the footswitch works).  I'm still not 100% sure on the foot switch and power supply.  I haven't had a chance to draw it up.  Also I wasn't sure if the terminal blocks wired one side to the other, or wired above to below  - need to look at it again.

For the Tremolo:

Quote
gonna post the graphic ,
but trem speed pot

trem intensity i had afu

The new intensity connection makes 100% sense now.   That's how I drew it before but it didn't agree with the wiring so we changed it.

Apart from the now fix green wire connection that I had the writing against, the speed pot wiring was actually correct before.  You actually flipped the speed pot and the numbers to make it the same as before.  However when you changed the numbers is now causes a disagreement between the edge connection numbers and the parts on the PCB - we can't move those.   So the correction is
- remove that dubious green wire from the trem switch to the speed pot
- wire the trem switch to the intensity pot
- leave the speed pot wires and number as they were in the V2.1 schematic.

I'll add the labels to the Trem "outputs" to the channels.   They got left off somewhere along the way.

PSU:
Quote
i'm beginning to realize we're gonna have to get the power supply right, too, unless ya wanna just say screw it and let peeps use whatever they want. for posterity sake, and any poor loser who dare tread here trying to fix one, it would be kind of us to do i guess. pretty lazy tho.
Yes, if you want to play with footswitch I think we need to get all that down on paper.  You wiring notes cover most of it.

I need to read over your new PSU pic.

Early on you mentioned the mixer was at 22V and the reverb and fuzz were at 9V.   Is that still true?   IIRC, there are four power rails.  They had 1k resistors and there circuit didn't look like it pulled enough current to drop 22V to 9V across 1k's.


Quote
i had to ditch the 3906. playing with it today, it just plain sounded lousy. yeah, it was a little louder, but really just too farty and gross. so i replaced that mofo with the ac125 i first tried in the pedal...
yeah...
You have to do what you have to do.  ;D

Quote
ok. also finished the footswitch. i smoked one of 'em. haven't done that in years!
Too many 3:00am's

Quote
messy inside, recycled amp footswitch, had to drill some holes and mess with wiring some to get it working right, so a bit ugly, but functional. i just tied the three resistors together and soldered the white wire i added to the center pin of the plug for powering the whole mess.
Things with missing footswitches are always a pain.  They get very little air-play in the docs to work it out.

And a purple mojo led ...
(https://pbs.twimg.com/media/DaTOiwKXcAA9TVt.jpg)

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 16, 2019, 06:43:59 PM
i had to check that pic,it wasn't loading, so i downloaded it, re-upping here.


(https://i.postimg.cc/hJxwxwPs/hend-mad.jpg) (https://postimg.cc/hJxwxwPs)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 16, 2019, 07:13:49 PM
Quote
For the Reverb:
Quote
all the circled numbers on the schematic have been traced, beeped, verified and corrected for which pins they actually go to. its possible i have the pnp's connections backwards, as i'm not sure if the emitter is actually the reverb drive or the ground.  that part i had to guess. if it makes sense switching ONLY those two connections, thats hip, cuz one of the two terminates in the chassis ground off the tank itself, carried there in the shield of the cable.
Hmmm, so really, that leaves up with the reverb connections unresolved/whacky.   Have you confirmed the reverb tank is internally grounded?  It's not a normal thing to do and even less normal for the drive side to be grounded even more so the tip - totally bizarre!   The PNP pin-out looks fine from the transistor data, the PCB and the way it is wired in the circuit.

somethings getting lost here in translation again. the connection there to pins 10 (HOT) and 11 (shield) on the socket are what they are.  i'm not sure which side of the drive amp is supposed to be "the output".

the tip/hot is most def NOT grounded. and the side that has the ground strap to it i believe is the reverb tank output side, not the input side. somehow things here n there got reversed, so we're both trying to figure it out. i dunno enough about reverbs to know where the output is suppposed to be taken from on the drive amp... the e of the pnp? or the 680 r resistor? i'd assume the shield would go to the e, but... in that case, the ground connection would travel thru the shield to the tank, and then terminate in the corner on the other short side of where the tank output is.

sorry... like you said, too many 3 am's lol

Quote
Quote
just curious. its 2019, be nice to let the verb "splash " when ya kill it.
Cutting the tank input line might do that since there is DC through the input coil (from what I can see).
Normally you wouldn't want that though.[\quote]

who ever said i'm normal ?????? ;)
Quote
Quote
do ya think there's a way to kill the reverb from the footswitch, but change it from the output of the verb to the input?
maybe switch the footswitch from killing the output of the verb, to shorting the input to ground instead? or is that gonna be POP!! causing issues with noise and stuff?
There's many ways to do it.   Some methods may invoke the evil hum spirit, either due to the length of the wiring or where the grounding point are made (or due to restriction in the way the footswitch works).  I'm still not 100% sure on the foot switch and power supply.  I haven't had a chance to draw it up.  Also I wasn't sure if the terminal blocks wired one side to the other, or wired above to below  - need to look at it again.

i don't really NEED to do it, i just find it weird to here the reverb die like that in this modern age lol.
the cable to the footswitch is about 22 feet long, so yeah, hum could be an issue for sure.

right now, due to the weird wiring i stumbled on and doc'd last nite, its fairly quiet, and works well with very little "popping". every other way i tried was inSANE. popping? shit, EXPLOSIONS ffs. lol

and did i mention i'm fairly lazy?


Quote
For the Tremolo:

Quote
gonna post the graphic ,
but trem speed pot

trem intensity i had afu

The new intensity connection makes 100% sense now.   That's how I drew it before but it didn't agree with the wiring so we changed it.

Apart from the now fix green wire connection that I had the writing against, the speed pot wiring was actually correct before.  You actually flipped the speed pot and the numbers to make it the same as before.  However when you changed the numbers is now causes a disagreement between the edge connection numbers and the parts on the PCB - we can't move those.   So the correction is
- remove that dubious green wire from the trem switch to the speed pot
- wire the trem switch to the intensity pot
- leave the speed pot wires and number as they were in the V2.1 schematic.


yes, exactly... i believe that that is all 100% correct now.
sure seems to make more sense. i didn't remove the dubious green wire in the updated graphic
i digitally molested last nite.

Quote

I'll add the labels to the Trem "outputs" to the channels.   They got left off somewhere along the way.

that will certainly help MY dumb ass!! lol... btw, which of the resistors do you think are limiting the trem depth? maybe change R6 from 100k to 47k, or even 10k? or will that make it unstable?
i have barely messed with trems at all. generally me and anything that oscillates can't seem to get a long ;)


Quote
PSU:
Quote
i'm beginning to realize we're gonna have to get the power supply right, too, unless ya wanna just say screw it and let peeps use whatever they want. for posterity sake, and any poor loser who dare tread here trying to fix one, it would be kind of us to do i guess. pretty lazy tho.
Yes, if you want to play with footswitch I think we need to get all that down on paper.  You wiring notes cover most of it.

I need to read over your new PSU pic.

it should be dead on the money. but... if something should be green and i say blue, or should be yellow and i say white, thats this goddamn glaucoma. i can't tell some colors apart without super brite light anymore.

btw, it appears the terminal blocks pass THRU the chassis i think, from the power supply side to the pcb side. i will try and beep it out to be sure.

i know the center terminals DO connect thru for sure.


Quote
Early on you mentioned the mixer was at 22V and the reverb and fuzz were at 9V.   Is that still true?   IIRC, there are four power rails.  They had 1k resistors and there circuit didn't look like it pulled enough current to drop 22V to 9V across 1k's.

after changing the q's on the fuzz board, i get 25-0-25 off the transformer.
most of the boards seem to run about 16volts, the fuzz runs at about 11. reverb, too.
the voltage definitely has changed since we started with it.

one thing thats a bitch tho, is to get at the pinouts for the sockets, you usually gotta pull a board to get at the ones in back... and when ya pull a board? the voltage seems to go up a volt or two. so that's probably where some discrepancies came from too.

also.... while i remember... in SOME cases, sockets have multiple connections to the same pins, and in SOME cases, the color coding changes when it leaves the socket... mosty on the osc board for the tuner if memory serves, but that could account for some weirdnesses too. once i can see all the schematics together, hopefully i can match up all the connections so the whole bloody mess makes a little more sense.



Quote
Quote
i had to ditch the 3906. playing with it today, it just plain sounded lousy. yeah, it was a little louder, but really just too farty and gross. so i replaced that mofo with the ac125 i first tried in the pedal...
yeah...
You have to do what you have to do.  ;D

now, when ya kick it in, it just sounds like natural overdrive, that nice tubey sound only ge can give. no boost in volume, and ya gotta peg the fuzz, but thats ok, i'd rather have a useable overdrive i can add fuzz to than an unruly fuzz that's just plain.... not that great.

lol.. of course, i also learned why i need to put a three prong power on it and ditch the reverse switch, as last nite this thing was humming louder than a pack of harleys lol

Quote

Quote
ok. also finished the footswitch. i smoked one of 'em. haven't done that in years!
Too many 3:00am's

Quote
messy inside, recycled amp footswitch, had to drill some holes and mess with wiring some to get it working right, so a bit ugly, but functional. i just tied the three resistors together and soldered the white wire i added to the center pin of the plug for powering the whole mess.
Things with missing footswitches are always a pain.  They get very little air-play in the docs to work it out.

And a purple mojo led ...
(https://pbs.twimg.com/media/DaTOiwKXcAA9TVt.jpg)

well, the important thing is, we CRACKED THIS SUCKAH!!
the footswitch will be handy for some poor guy someday i am sure.
it DOES make it noisier, but its not THAT bad.

we'll carry onward. gonna go hit the dungeon and see what happens. i will try and beep out the connections on the terminal blocks to see if they do indeed pass thru the chassis from one side to the next.

more later ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 18, 2019, 05:36:37 PM
Quote
somethings getting lost here in translation again. the connection there to pins 10 (HOT) and 11 (shield) on the socket are what they are.  i'm not sure which side of the drive amp is supposed to be "the output".

the tip/hot is most def NOT grounded. and the side that has the ground strap to it i believe is the reverb tank output side, not the input side. somehow things here n there got reversed, so we're both trying to figure it out. i dunno enough about reverbs to know where the output is suppposed to be taken from on the drive amp... the e of the pnp? or the 680 r resistor? i'd assume the shield would go to the e, but... in that case, the ground connection would travel thru the shield to the tank, and then terminate in the corner on the other short side of where the tank output is.
I'm pretty sure the output of the amplifier which drives the tank input should go to R8 (pin #11) and ground.  I'm not overly concerned about the shield going to the output pin.  They might be flipping the phase of the reverb so it adds back to the dry signal correctly.

I'm mainly concerned with the fact with haven't proven the tip does connect to ground.  In fact if the Tank input tip *is* wired to Reverb pin10 we have already accounted for both Tank inputs.   In that case it doesn't makes sense for there to be a ground at the reverb.  If the Tank input when to ground at the reverb it would effectively short pin 10 to ground and that would kill the reverb drive entirely (as it shorts the drive amp input to ground through the reverb).

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right now, due to the weird wiring i stumbled on and doc'd last nite, its fairly quiet, and works well with very little "popping". every other way i tried was inSANE. popping? shit, EXPLOSIONS ffs. lol
I don't understand it yet but when I look at the circuit the wierd R12 R13 thing makes me think someone tinkered with the values to reduce the pop when switching.

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the cable to the footswitch is about 22 feet long, so yeah, hum could be an issue for sure.
So if you went down that road you would need a relay or JFET (or maybe transistor) to switch audio at the amp end and only run the control signal down the footswitch wire.

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which of the resistors do you think are limiting the trem depth? maybe change R6 from 100k to 47k, or even 10k? or will that make it unstable?
R6 will probably do something.  My initial impression is R12 and R18 are limiting the depth.  So reducing those might increase the depth.   The way I look at it is the tremolo modulates the gain of the last stage of the channel amps.   The minimum gain is when the Vactrols are open leaving 6.8k's in the emitters.  The maximum gain is when the Vactrols are shorted.  The series resistance limits the the minimum resistance to 1.5k.  1.5k in parallel with 6.8k is 1.2k.    So the gain can't change more than about 6.8 / 1.2 = 5.7.     Now that assumes the Vactrols are being driven from close to short to open.  Maybe they aren't and if not R6 might work too; maybe R6 an R12 and R18 all need tweaking, it comes down to the specifics of what the Vactrol resistance is.
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it should be dead on the money. but... if something should be green and i say blue, or should be yellow and i say white, thats this goddamn glaucoma. i can't tell some colors apart without super brite light anymore.
Not good.  I haven't had a chance to go over it in detail.

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after changing the q's on the fuzz board, i get 25-0-25 off the transformer.
most of the boards seem to run about 16volts, the fuzz runs at about 11. reverb, too.
the voltage definitely has changed since we started with it.
OK thanks - cool.

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one thing thats a bitch tho, is to get at the pinouts for the sockets, you usually gotta pull a board to get at the ones in back... and when ya pull a board? the voltage seems to go up a volt or two. so that's probably where some discrepancies came from too.
Yeah, that whole area is a mystery to me.

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well, the important thing is, we CRACKED THIS SUCKAH!!
the footswitch will be handy for some poor guy someday i am sure.
it DOES make it noisier, but its not THAT bad
Yes we aren't too far off.   I guess we have gone a lot further than just fixing the thing :icon_mrgreen:






Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 18, 2019, 09:36:42 PM
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somethings getting lost here in translation again. the connection there to pins 10 (HOT) and 11 (shield) on the socket are what they are.  i'm not sure which side of the drive amp is supposed to be "the output".

the tip/hot is most def NOT grounded. and the side that has the ground strap to it i believe is the reverb tank output side, not the input side. somehow things here n there got reversed, so we're both trying to figure it out. i dunno enough about reverbs to know where the output is suppposed to be taken from on the drive amp... the e of the pnp? or the 680 r resistor? i'd assume the shield would go to the e, but... in that case, the ground connection would travel thru the shield to the tank, and then terminate in the corner on the other short side of where the tank output is.
I'm pretty sure the output of the amplifier which drives the tank input should go to R8 (pin #11) and ground.  I'm not overly concerned about the shield going to the output pin.  They might be flipping the phase of the reverb so it adds back to the dry signal correctly.

I'm mainly concerned with the fact with haven't proven the tip does connect to ground.  In fact if the Tank input tip *is* wired to Reverb pin10 we have already accounted for both Tank inputs.   In that case it doesn't makes sense for there to be a ground at the reverb.  If the Tank input when to ground at the reverb it would effectively short pin 10 to ground and that would kill the reverb drive entirely (as it shorts the drive amp input to ground through the reverb).

the tip doesn't connect to ground bro. the tip connects to the tip. that's pin 10. the sleeve connects to pin 11, and pin 12 is grounded, but to a specific point.

what i'm not sure is where the signal comes from that goes down the shielded wire, if it exits the circuit from the 680r resistor, or e of q2 is what i mean. to me, it seems either would probably have signal on it.

ok. just compared the overlay to the schematic. we definitely are still reversing some connections.
pin 10 becomes pin 3 when ya flip the board. which appears to have happened.

again. ;)

so... we'll reverse shit and go with the pinout you prefer, which is 180 opposite of mine.

reverb socket pin 1 reverb send shield (reverb drive amp)
reverb socket pin 2 no connection
reverb socket pin 3 blue wire to terminal block #2, side a #3
reverb socket pin 4 reverb level 2
reverb socket pin 5 key
reverb socket pin 6 reverb send hot/tip (reverb drive amp)
reverb socket pin 7 green wire to reverb level 3
reverb socket pin 8 purple wire to mixer pin #11
reverb socket pin 9 orange wire to terminal block #1, side b, pin #5
reverb socket pin 10 reverb return tip/hot (reverb recovery amp)
reverb socket pin 11 reverb return shield (reverb recovery amp)
reverb socket pin 12, ground at mixer pin #8

i just messed with the drawing a little, compared my notes to the schematic and the parts overlay,
and this is definitely gotta be it on this drawing. we had the pinouts opposite each other.
remember, i was describing from the COMPONENT side of the board, not the trace side when numbering, as in the amp its opposite the way the fuzz is.
so all our connections are backwards from each other.
(https://i.postimg.cc/18ZM9k30/verb-correct-maybe-2.png) (https://postimg.cc/18ZM9k30)

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right now, due to the weird wiring i stumbled on and doc'd last nite, its fairly quiet, and works well with very little "popping". every other way i tried was inSANE. popping? shit, EXPLOSIONS ffs. lol
I don't understand it yet but when I look at the circuit the wierd R12 R13 thing makes me think someone tinkered with the values to reduce the pop when switching.

r12/13 on which board?
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the cable to the footswitch is about 22 feet long, so yeah, hum could be an issue for sure.
So if you went down that road you would need a relay or JFET (or maybe transistor) to switch audio at the amp end and only run the control signal down the footswitch wire.[\quote]

yeah, probably the easiest way to do it, but i'll really need help cuz i haven't tried a transistor as a switch yet, tho it looks kinda easy... still gotta pass power down the cable tho to power the led's, wondering if its worth it to add another daughterboard inside the unit or not.
if ya crank the preamp fairly loud, and turn the amp down, its pretty quiet.

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which of the resistors do you think are limiting the trem depth? maybe change R6 from 100k to 47k, or even 10k? or will that make it unstable?
R6 will probably do something.  My initial impression is R12 and R18 are limiting the depth.  So reducing those might increase the depth.   The way I look at it is the tremolo modulates the gain of the last stage of the channel amps.   The minimum gain is when the Vactrols are open leaving 6.8k's in the emitters.  The maximum gain is when the Vactrols are shorted.  The series resistance limits the the minimum resistance to 1.5k.  1.5k in parallel with 6.8k is 1.2k.    So the gain can't change more than about 6.8 / 1.2 = 5.7.     Now that assumes the Vactrols are being driven from close to short to open.  Maybe they aren't and if not R6 might work too; maybe R6 an R12 and R18 all need tweaking, it comes down to the specifics of what the Vactrol resistance is.

should i get a reading off of them? would i have to unsolder one end like with resistors, or just clamp my meter to them? pink don' knows nothin' bouts no vactrols....
the trem is actually pretty sweet since i changed the fuzz around.

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it should be dead on the money. but... if something should be green and i say blue, or should be yellow and i say white, thats this goddamn glaucoma. i can't tell some colors apart without super brite light anymore.
Not good.  I haven't had a chance to go over it in detail.

yeah, when i hooked up power for the footswitching, i looked EVERYwhere for the "white" wire i'd found the nite before... only to discover in daylight it was yellow, not white. glaucoma sucks... even with COPious amounts of... cof.. medicine


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after changing the q's on the fuzz board, i get 25-0-25 off the transformer.
most of the boards seem to run about 16volts, the fuzz runs at about 11. reverb, too.
the voltage definitely has changed since we started with it.
OK thanks - cool.

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one thing thats a bitch tho, is to get at the pinouts for the sockets, you usually gotta pull a board to get at the ones in back... and when ya pull a board? the voltage seems to go up a volt or two. so that's probably where some discrepancies came from too.
Yeah, that whole area is a mystery to me.

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well, the important thing is, we CRACKED THIS SUCKAH!!
the footswitch will be handy for some poor guy someday i am sure.
it DOES make it noisier, but its not THAT bad
Yes we aren't too far off.   I guess we have gone a lot further than just fixing the thing :icon_mrgreen:

yeah, we done good bro.
when all was said and done, i ended up with a pair of ge's in the amp itself, i had to go a bit higher gain than i wanted, but it got a nice overdrive to it. as ya turn the fuzz mix pot, it actually phases against the channel settings, allowing quite a wide range of tones.

i used an ac176/ac128 combo for the npn/pnp respectively.

in the standalone, its gonna either need some values tweaked or really low gain q's.
right now i've been trying to choose between two different ge npn's for q1. i've got an ac128 in q2 which seems happy there.
but its so weird. it wants LEAKAGE to be happy in q1. not too much, not too little.
in q2, the ac128 reads 89hFE with 108mv leakage <i can't do math, best i can offer, sorry>
in q1, i tried using a switch to choose transistors. it was actually kinda amusing, cuz at first i tried tieing e's and c's together and just switching b's. THAT was interesting. frankly, i liked it better... i could get a clear difference tween a nice overdrivey kinda warm ge tone, and a boosted much louder FUZZtone.

i may go back to it. still trying to decide. the other way leaves the b's connected and switches the e's and c's. it pops more, and i lose a bit of fuzztone and volume. interestingly, if i reverse beta one q, it gets a better fuzz and is about 4x louder!

anyways, in q1,
the first q on the switch is
2n1302 ge
hFE 36(!!!) with 226mV leakage.
reverse beta gives a very unapologetic 60's style fuzz, correct its like a warmish overdrive.

but the OTHER transistor, shit, i dunno what to make of it. its ge, marked o73 and is a VERY old q, one of the first that was available, a real antique. i picked a couple up years ago, and thought their gain too low. but man, in this fuzz, it really rips!
http://dsmcz.com/prestashop/unknown-spec-transistors/6466-transistor-4-073.html
i can't say what the gain is, cuz neither my meter nor my transistor tester can seem to read it.

it comes up as two opposing diodes with a tap in the center...
                                            2
like...  1--------I<--------------+----------------->I---------3
the left side reads 1.11v, the right side says 419mv

no idea!!!!! above my paygrade!
wondering if what its actually doing is conducting the input to the base thru to the collector to get amplified by the second stage.

every @#$%ing thing about this circuit is beyond weird!!!!!!!!!!!!!!!!!!!!

anyways, i await what ya think... let me know if the reverb looks right above.
it gets confusing for sure.. and often stuff got reversed between your notes and mine, so i've started looking at stuff the opposite way if it doesn't make sense, and then things seem to start to work. i think.

its like... take neon green. if you make it the opposite, ie negative, it becomes hot pink.

these sockets are like that. i think now, we're getting 'em right.

i'm gonna go play with transistors for another hour or so trying to find the optimal ones for the standalone. i've spent a good chunk of a couple days doing this, and got it narrowed down to the two.. do i go with the fuzzier tone, or the more overdrivey one?

@#$%! said pink... i likes 'em both!!

but, saith the voice of reason... dude... yer using GE. its gonna sound different EVERY SINGLE TIME
lol

i think i've found my own private hell ;)   :icon_twisted:
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 18, 2019, 10:30:03 PM
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the tip doesn't connect to ground bro.
When you were talking about the reverb being grounded at the reverb end I thought you meant, *in order to fix the reverb drive issue* the Tank input "tip" was ground *at the reverb*. I understand the tip is not ground at the Reverb board side and goes to Reverb #10.    I think I misunderstood which terminal you said was grounded at the reverb.   It's the shield on the Tank Output - yeah?    Sometimes that *is* done whenever the Reverb Tank casing cannot come in contact with chassis ground - like when it is mounted on the wooden base of an amp, or isolated with rubber gromets.   The Tank Input usually floats both terminals.

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ok. just compared the overlay to the schematic. we definitely are still reversing some connections.
pin 10 becomes pin 3 when ya flip the board. which appears to have happened.

again.
...

so all our connections are backwards from each other.
I'm pretty sure all the connections on the last dump of "revision 2.1" schematics are correct.    If you look at your reverb markup and my latest Reverb V2.1 schematic all the connections now agree.  Your markup was on V1.0 which *did* have the reversals.

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what i'm not sure is where the signal comes from that goes down the shielded wire, if it exits the circuit from the 680r resistor, or e of q2 is what i mean. to me, it seems either would probably have signal on it.
Ok the drive definitely comes out of Q2's collector then though R8 (680R) then to the reverb tank input (shield).   That's part makes 100% sense to me.

The hanging issue is where the other end of the drive goes ie. the Tank Input tip.   Based on the current wiring and schematics:  it goes to Reverb #10 which then goes to R1 on the schematic.  This matches the V2.1 Reverb Schematic and your wiring.   You can see pin #10 goes to R1 on the overlay,

(https://i.postimg.cc/v1VVJ2jB/Reverb-Pin-10.png) (https://postimg.cc/v1VVJ2jB)

So if all the checks point to that - it must be like that?

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r12/13 on which board?
On the reverb board.

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should i get a reading off of them? would i have to unsolder one end like with resistors, or just clamp my meter to them? pink don' knows nothin' bouts no vactrols....
the trem is actually pretty sweet since i changed the fuzz around.
It's a bit tricky as the resistance gets modulated and you will end-up with fluctuating results, which could be useless.   Given we have nothing to lose give it a try.   You could measure the resistance across the vactrols when the both Trems are disabled.  Measure both Vactrols.   That might help work out the centre.  However it doesn't really tell us if it swings closer to open or closed.

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even with COPious amounts of... cof.. medicine
One of my bosses had that (he was a good guy).   He had it under control but I'm sure there's varying degrees of the symptoms.

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when all was said and done, i ended up with a pair of ge's in the amp itself, i had to go a bit higher gain than i wanted, but it got a nice overdrive to it. as ya turn the fuzz mix pot, it actually phases against the channel settings, allowing quite a wide range of tones.
You might as well put all you can into it.

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nterestingly, if i reverse beta one q, it gets a better fuzz and is about 4x louder!
Hard to say what will happen.  It comes down to specifics and where the bias points end-up.

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                                            2
like...  1--------I<--------------+----------------->I---------3
the left side reads 1.11v, the right side says 419mv
If I saw that the first thing I would think of is it is a Darlington:  1=e, 2=b 3=c

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anyways, i await what ya think... let me know if the reverb looks right above.
it gets confusing for sure.. and often stuff got reversed between your notes and mine, so i've started looking at stuff the opposite way if it doesn't make sense, and then things seem to start to work. i think.
I think were are in agreement now.

I"m still not 100% happy about the Tank Input tip going to the input of the amp - it just looks totally whacked to me.


Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 19, 2019, 09:26:17 PM
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the tip doesn't connect to ground bro.
When you were talking about the reverb being grounded at the reverb end I thought you meant, *in order to fix the reverb drive issue* the Tank input "tip" was ground *at the reverb*. I understand the tip is not ground at the Reverb board side and goes to Reverb #10.    I think I misunderstood which terminal you said was grounded at the reverb.   It's the shield on the Tank Output - yeah?

yeah!!!!!!!

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   Sometimes that *is* done whenever the Reverb Tank casing cannot come in contact with chassis ground - like when it is mounted on the wooden base of an amp, or isolated with rubber gromets.   The Tank Input usually floats both terminals.

yeah, this is floated completely, rubber washers, and it connects funny... weird machine!

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ok. just compared the overlay to the schematic. we definitely are still reversing some connections.
pin 10 becomes pin 3 when ya flip the board. which appears to have happened.

again.
...

so all our connections are backwards from each other.
I'm pretty sure all the connections on the last dump of "revision 2.1" schematics are correct.    If you look at your reverb markup and my latest Reverb V2.1 schematic all the connections now agree.  Your markup was on V1.0 which *did* have the reversals.

hahahha i think i need sleep ;)


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what i'm not sure is where the signal comes from that goes down the shielded wire, if it exits the circuit from the 680r resistor, or e of q2 is what i mean. to me, it seems either would probably have signal on it.
Ok the drive definitely comes out of Q2's collector then though R8 (680R) then to the reverb tank input (shield).   That's part makes 100% sense to me.[/quote]

The hanging issue is where the other end of the drive goes ie. the Tank Input tip.   Based on the current wiring and schematics:  it goes to Reverb #10 which then goes to R1 on the schematic.  This matches the V2.1 Reverb Schematic and your wiring.   You can see pin #10 goes to R1 on the overlay,[/quote]

yep, thats right. i agree. somehow i guess i lost one of the graphics with a puter issue or something, or i AM that braindead or possibly both ;)



(https://i.postimg.cc/v1VVJ2jB/Reverb-Pin-10.png) (https://postimg.cc/v1VVJ2jB)

So if all the checks point to that - it must be like that?[/quote]

yes exactly correct

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r12/13 on which board?
On the reverb board.

i will take a peek in the morning when i have good light.

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should i get a reading off of them? would i have to unsolder one end like with resistors, or just clamp my meter to them? pink don' knows nothin' bouts no vactrols....
the trem is actually pretty sweet since i changed the fuzz around.
It's a bit tricky as the resistance gets modulated and you will end-up with fluctuating results, which could be useless.   Given we have nothing to lose give it a try.   You could measure the resistance across the vactrols when the both Trems are disabled.  Measure both Vactrols.   That might help work out the centre.  However it doesn't really tell us if it swings closer to open or closed.

tried, my shitty meter is acting up and i couldn't get a "range" where anything seemed to show up.
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even with COPious amounts of... cof.. medicine
One of my bosses had that (he was a good guy).   He had it under control but I'm sure there's varying degrees of the symptoms.

stuff just slowly gets.... dimmer.

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when all was said and done, i ended up with a pair of ge's in the amp itself, i had to go a bit higher gain than i wanted, but it got a nice overdrive to it. as ya turn the fuzz mix pot, it actually phases against the channel settings, allowing quite a wide range of tones.
You might as well put all you can into it.

when i get a chance to actually breadboard the thing, i'll play with values to adjust it to sound a bit better. i'm imagining the bias is way off from where it should be to get the circuit to sound its best.


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nterestingly, if i reverse beta one q, it gets a better fuzz and is about 4x louder!
Hard to say what will happen.  It comes down to specifics and where the bias points end-up.

and a whole lotta leakage!! ;)
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                                            2
like...  1--------I<--------------+----------------->I---------3
the left side reads 1.11v, the right side says 419mv
If I saw that the first thing I would think of is it is a Darlington:  1=e, 2=b 3=c

wow. weird, the only time i've seen it on the little chinese transistor checker do that is with really leaky germanium. sometimes it will read them as jfets. weird. ;)
did they make germanium darlingtons?
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anyways, i await what ya think... let me know if the reverb looks right above.
it gets confusing for sure.. and often stuff got reversed between your notes and mine, so i've started looking at stuff the opposite way if it doesn't make sense, and then things seem to start to work. i think.
I think were are in agreement now.

I"m still not 100% happy about the Tank Input tip going to the input of the amp - it just looks totally whacked to me.

wayyyyyyyydaminnit... i think i'm suddenly misunderstanding this again. where the hell does the signal to be reverberated COME from? cuz yeah, it sure seems weird looking at it, but its gotta be what its gotta be.
the only explanation i can get would be reverse #11 and #2 again, cuz it can only be one or the other. #2 has no connection AFAIK!

so... the input to the reverb drive amp comes from ????????????? would have to be the mixer, right?
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 20, 2019, 04:24:57 PM
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So if all the checks point to that - it must be like that?

yes exactly correct
It's just weird!  weird weird weird ...  (skips off in the distance with a crazed laugh)

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tried, my shitty meter is acting up and i couldn't get a "range" where anything seemed to show up.
Well, you could do an experiment and put a 470R ohm in parallel with the 1k5's.

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wow. weird, the only time i've seen it on the little chinese transistor checker do that is with really leaky germanium. sometimes it will read them as jfets. weird. ;)
did they make germanium darlingtons?
Leakage could make cause the tester to show dodgy results.  Maybe check the "diode" voltages directly with a DMM.

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wayyyyyyyydaminnit... i think i'm suddenly misunderstanding this again. where the hell does the signal to be reverberated COME from? cuz yeah, it sure seems weird looking at it, but its gotta be what its gotta be.
the only explanation i can get would be reverse #11 and #2 again, cuz it can only be one or the other. #2 has no connection AFAIK!

so... the input to the reverb drive amp comes from ????????????? would have to be the mixer, right?

From what I can see with the current set-up:  one side of the drive comes from the 680ohm (Reverb pin #11), the other side comes from Reverb pin #10.   However, the input to the reverb drive amp (ie. the input of the reverb "block" in the bigger picture)  is also on Reverb pin #10  the input signal to the drive amp comes from Mixer pin #4.     The weird thing is the reverb spring is wrapped from the out back the input of the reverb drive amp.   So that *is* how it appears to be connected.  However, to me it makes no sense and every time I look at it red lights flash and I hear a robot voice saying does not compute.   To me the input and output are at wrong phase for that connection and the impedance driving the input is too high.

Anyway I can explain where an input the Reverb is coming from (Mixer pin #4 to Reverb pin #10)  but the connection of the Tank Input is screwed.



Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 20, 2019, 08:02:03 PM
ok, that all makes sense... at least as much as can be made with this monstrosity!!

i'm ASSUMING the weird shit is cuz everything is in parallel. right up until ya peg it its fairly weak to normal, but when ya peg it... the channels, reverb, or fuzz... everything kinda saturates.

this is the weirdest thing i ever dealt with!

if you're as sick of messing with it as i am getting to be, let me know, and i'll call this nut cracked, at least cracked enough. the main missions were to remake the fuzz, and get it working, so mission accomplished, the rest is cake i think.

i wanna thank you for the help, and more, for the hang, bro.  you rock. let me know what ya wanna do... if ya wanna finish the beast off for posterity, i can get whatever data remains. if ya think we're good, i'm good with that, too. my job has been the easy part, you've done all the heavy lifting, so i'm leaving the final decision up to you!

 :icon_mrgreen:

now, i'm-a gonna go build me a flangerlicious pedal while i await your reply. ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 20, 2019, 08:58:08 PM
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this is the weirdest thing i ever dealt with!
Same here.   It's just different enough to put you off the scent at every step.  Normally I can guess what is going on but I can only put a 20% confidence on any guesses with that thing.

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i wanna thank you for the help, and more, for the hang, bro.  you rock. let me know what ya wanna do... if ya wanna finish the beast off for posterity, i can get whatever data remains. if ya think we're good, i'm good with that, too. my job has been the easy part, you've done all the heavy lifting, so i'm leaving the final decision up to you!
No worries at all.  It would probably be a good thing to polish off the switching and PSU.  I scared to go there because it might open another can of confusing worms.   I had a dream about tracing the tuner.  That might take a while.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 21, 2019, 12:04:15 AM
heheheh

well, since its in parallel, ummm... want me to pull the dang board n just mail it to you?

;) may be easier than me messing stuff up again.
i must warn you tho
that some of the missing connections, or connections that make no sense probably jumper to the tuner board.

but what the hell, in for a dollar, in for a dime, i'll start getting the last of the info asap.

and hey!!!
them "vactrols" ain't vactrols i don't think. they only have three legs, and appear to be some kind of diode-y thing. i found one almost identical to the ones on the tremolo in my semi junk drawer and it had the same markings. tried to look it up, i don't see anything else like it.

the preamp, by itself, now has a really nice vintage tone, the fuzz sounds like tube distortion, the reverb is pretty much killer AND the tremolo sounds almost more like a vibe on the lower strings.. very phasey.

i will get a picture of the dang component, i meant to bring it upstairs with me but forgot all about it. need sleep. lol

rock on bro
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 21, 2019, 12:40:16 AM
rob,
on the tremolo board, could it be some kind of weird schotke diode?
cuz them black things on the tremolo board have three terminals pokin' into the board, and the markings on the front look just like the ones on this, but double, kinda...


(https://i.postimg.cc/w1H15dn2/Screenshot-2019-02-21-Sourcingmap-30-A-100-V-3-Terminal-Schottky.png) (https://postimg.cc/w1H15dn2)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 21, 2019, 05:09:34 PM
Quote
well, since its in parallel, ummm... want me to pull the dang board n just mail it to you?

;) may be easier than me messing stuff up again.
i must warn you tho
that some of the missing connections, or connections that make no sense probably jumper to the tuner board.
I wouldn't separate it from the unit.  The board is pretty much irreplaceable and should be kept with the mothership.   Whatever I get done is fine.  If you feel like getting the values in the future that's fine - I'll pencil it in for 2030  ;D.

Quote
and hey!!!
them "vactrols" ain't vactrols i don't think. they only have three legs, and appear to be some kind of diode-y thing. i found one almost identical to the ones on the tremolo in my semi junk drawer and it had the same markings. tried to look it up, i don't see anything else like it.
To be honest, I'm not 100% sure what they are.   I drew them as vactrols with a common "LED" + resistance terminal.  That configuration should work (there are some issues with feedthrough in the Ovation ckt).     The part numbers looked a bit like some opto part numbers I've seen in the past.   I could not find any info on them.    It's on my "to do" list.   In 1969 there was probably all sort of weird parts floating around.   Parts that didn't work out disappeared and by the mid 70's the electronics world was largely what we see today.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 21, 2019, 06:22:42 PM
its some kind of diode bridge or rectifier... wondering if thats why it sounds so phasey?

this is what was in my junk drawer, the markings are the same... i googled a metric arse load of vintage diodes and found nothing particularly close other than maybe this:

https://www.silicon-ark.co.uk/rvd10dc4r-dual-diode-by-international-rectifier

(https://www.silicon-ark.co.uk/image/cache/catalog/data/bespoke/rvd10dc4r-diode-national-panasonic-500x500.jpg)

we need to get rg and mark n paul and jc in here so somebody can figure this out! lol


(https://i.postimg.cc/7fgNBb2v/diodey-thing-1.png) (https://postimg.cc/7fgNBb2v)


these are the two best crappy pics i could get of the things. they are marked with the same thing as the one i have and ones i've seen. apparently the "dot" is where the common cathode or anode ends up, depending on which way the diodes drawn on it face.

i will endeavor to get readings off the one i found tomorrow.



(https://i.postimg.cc/fJZdRCJF/diodey-thing-2.png) (https://postimg.cc/fJZdRCJF)

(https://i.postimg.cc/kVk63F0T/diodey-thing-3.png) (https://postimg.cc/kVk63F0T)

the ones in the unit, the top is epoxyed, makes me suspect its like, just two diodes in there. i have heard of diode based phasers AND trems, maybe this is what it is?
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 21, 2019, 06:46:30 PM
Quote
these are the two best crappy pics i could get of the things. they are marked with the same thing as the one i have and ones i've seen. apparently the "dot" is where the common cathode or anode ends up, depending on which way the diodes drawn on it face.

i will endeavor to get readings off the one i found tomorrow.
Cool.  Yes!!!! They definitely are a dual diode device.

I can't quite make it out but to me it looks like, from left to right
(1)---A1--->|---K1---(2)---A2--->|--- K2---(3)

So the diodes point in the same direction.   Is that how you see it?
(In your "red and black" rectifier the diodes point to the centre terminal (2) which is much more common.)

So in the trem circuit, the general connections are,
Rectifier pin 1 to Collector
Rectifier pin 2 to channel amps
Rectifier pin 3 to Emitter

The lower diode, pin 2 to pin 3, is the variable resistance.
I can only assume the diode, pin 1 to pin 2, helps the tremolo transistor keep in the good range of bias voltages.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 21, 2019, 07:10:25 PM
i forgot my bol, am on my way out the door to my thursday thing, so i will check cuz i gotta go down there anyways... gimme a second bro

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 21, 2019, 07:20:11 PM

0---->I--0--->I----0 is the marking in the ovation, and the same as the diode thing i found bro. so its def a dual diode!! cool!!

so thats in/anode cathode /center tap/ to anode to cathode/out?
i wonder if thats why it sounds so phasey. more of phase shift maybe than a trem?

stay tuned to this bat station!!! lol

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 21, 2019, 07:45:33 PM
Quote
so thats in/anode cathode /center tap/ to anode to cathode/out?

 in/anode
 out/center tap
 common point/ cathode

Quote
i wonder if thats why it sounds so phasey. more of phase shift maybe than a trem?
[/quote]
Normal diodes dont make it sound phasey, more distorted or you get ticks in sync with the LFO.
Phasey might the be due to the coupling cap between trem and the channel.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 21, 2019, 09:18:34 PM
This is the only info I could find,

(https://i.postimg.cc/qz9Y8bJ2/GE-Silicon-Rectifier-Modules-1972.png) (https://postimg.cc/qz9Y8bJ2)

The part number you gave kind of follows the pattern even though there are a few holes.
I'm pretty sure there's a datasheet somewhere elaborating on more options and details.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 22, 2019, 01:34:50 PM
https://www.digchip.com/datasheets/5897984-ld6935l-dual-low-dropout.html

LD6935L
Category   
Title   Dual low-dropout regulators, high PSRR, 300 mA
Description   The LD6935 series consists of small-size dual Low DropOut regulators (LDO). Each device delivers two times 300 mA with a typical voltage drop of 240 mV at 300 mA for each LDO. Each device offers two individual fixed nominal output voltages (VO(nom)) from 1.2 V to 3.6 V.
The LDO has an integrated Soft start to control the inrush current during start-up. The output states when disabled can be high‑ohmic 3‑state or auto discharge. Optionally a delayed output circuit is available for the second output. The devices are available in DFN1612‑8 (SOT1225) plastic package with a height of 0.4 mm.
Extremely low standby current in shutdown mode (≤ 0.1 μA)
Low quiescent current
Low output noise
Fast turn-on time
High Power Supply Rejection Ratio (PSRR)
Auto discharge or high‑ohmic mode for output states when disabled
Delayed output circuit for second LDO (optional)
DFN1612-8 (SOT1225) leadless package 1.6 x 1.2 x 0.4 mm
Pb-free, Restriction of Hazardous Substances (RoHS) compliant, free of halogen and antimony (Dark Green compliant)

i thought this may be it until i saw the damn datasheet
https://www.digchip.com/datasheets/parts/datasheet/1019/LD6935L-pdf.php

the one in my junk drawer is a dual SELENIUM rectifier. assuming the ovation is the same. google and nte searches have turned up ONE OTHER ONE very similar to the one i have.

gonna keep lookin'!! its just a matter of time... all there base are belong to us lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 22, 2019, 04:16:05 PM
Quote
LD6935L
I'm pretty sure that's the date code 69 = 1969.

It's like a fluke that the date code is the same as a part number.
There's no way that regulator was around in 1969.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 22, 2019, 05:55:51 PM
agreed. i'm gonna take some measurements of the one i found in my junk drawer, and will post them to see what's what... hopefully can narrow it down.

from what i've been reading on the hifi sites, these can often be replaced with 2 diodes and a current limiter resistor.

still trying to find an exact-ish example somewhere, but i have a feeling its gonna be wicked hard to find. not that it's not out there...

maybe i should contact haveyouseenhim and see if he still has access to that surplus electronics place

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 22, 2019, 06:08:21 PM
Quote
from what i've been reading on the hifi sites, these can often be replaced with 2 diodes and a current limiter resistor.
Honestly I'd try just two 1N4148's.

The way it's used in the circuit the two diode don't even have to be matched.  Only one diode is used as the variable resistor.


Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 22, 2019, 10:39:59 PM
hahahah,
so, in fitting with  everything else, one more example of why the hell would they bother using dual diodes if they coulda just stuck a simple diode in its place?

man... these guys musta been on acid lol

i'm gonna head for the dungeon, dunno if i'll mess with it tonite much tho, kinda burnt and very lazy ;)

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 22, 2019, 11:38:15 PM
found these guys
https://cougarelectronics.com/power-conversion-components/selenium-rectifier-suppressor/

the dual diode i believe is selenium, tho i may be wrong.. it had this to say tho, so i thought it may be relevent:

SELENIUM POWER RECTIFIERS

A selenium rectifier is an electronic component that permits free passage of electric current in one direction, but almost completely blocks the flow of current in the opposite direction. Like a silicon diode, when an alternating current is applied to a selenium rectifier in series with the load, half of the AC cycle is blocked and the load receives a pulsating direct current. by using two or more rectifiers in an appropriate center tap or bridge circuit, both halves of the AC cycle may be rectified !

Main parameters :

    Voltages: Standard Voltages per cell up to 36 v rms. The voltage rating is determined by the number of cells in series
    Current: Ratings are determined by the size of the cell, the number of cells in parallel, the circuit configuration and the type of cooling, Current Ratings of 0.5 amps for a 1.0 X 1.0 cell in a half wave configuration to 270 amps for a 8.0 X 16.0 cell in a 6 phase circuit.
    Circuits:Half wave, Doublers. Center Taps, Full Wave Bridges single and three phase.


this is the thing i found in my junk drawer

https://www.ebay.com/itm/IR-Selenium-Dual-Diode-DD05-repl-GE-K118J966-1-NIP/264197276052?hash=item3d83628194:g:etcAAOSw9GhYao2F
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 23, 2019, 12:17:53 AM
Quote
hahahah,
so, in fitting with  everything else, one more example of why the hell would they bother using dual diodes if they coulda just stuck a simple diode in its place?
I'm serious - really!  We should learn from our past and not ask why about anything on that unit.

Quote
SELENIUM POWER RECTIFIERS
I've played with a *lot* of selenium rectifiers in my time.   
I seriously doubt that device is selenium.   The part number you quoted doesn't look too far off a General Electric (GE) Silicon Rectifier.    I tried to find a GE datasheet with more complete info, which included that device, but I couldn't find much.

The selenium rectifier normally look like the link you posted,
https://duckduckgo.com/?q=selenium+rectifier&iax=images&ia=images

- open construction as opposed to moulded.
- made from plates (round, square, rectangular) stacked side by side
- a rod, screw, or rivet passing through the plates to hold it together
- the whole thing is usually covered in some sort of paint
- Some had 3 terminals (full-wave) and some had 5 (bridge)
- A very common thing was the outside terminal had to be linked together, like this,
https://www.cehco.com/wp-content/uploads/2015/01/K362B4EC1_SR7-300x235.jpg
(Some smaller ones folded the terminals together across the device.)
- Common ones were about 1"x1" (maybe 2A) but you could easily get 4"x4". 
  The smallest one I've seen was about 3/16" in diameter inside an analog meter.
  (Those little ones need to be fed a lot of electrons before they grow into the full size ones.)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 23, 2019, 12:49:40 AM
i had a whole box full of them ones. i was just thinking se cuz i saw some being advertised as se, and it seems like the description's kinda in line.

but hey... i know NADA!
i'm a monkey with a breadboard! ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 23, 2019, 01:03:14 AM
Quote
i had a whole box full of them ones. i was just thinking se cuz i saw some being advertised as se, and it seems like the description's kinda in line.

I'm sure at some point in the 60's GE produced a document which explained all their rectifiers and part numbers. 

I saw a few possible books and catalogs for sale but no PDF's.   No guarantee those books and catalogs cover the part in the Ovation. 

The sheet I posted comes out of a GE book but it's not a databook so it only contains short form info.

It's amazing how difficult it is to find data on old stuff some times, it quite literally has fallen of the planet.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 23, 2019, 01:18:01 AM
We need the diode or rectifier version of this document:

https://www.datasheet.live/index.php?title=Special:PdfViewer&url=https%3A%2F%2Fpdf.datasheet.live%2Fa8be1379%2Fgefanuc.com%2FC3513FB1AD1.pdf

https://pdf.datasheet.live/a8be1379/gefanuc.com/C3513FB1AD1.pdf

These page number is 1046 so the databook that came from might also have the rectifiers.

I think it's from this one,

https://archive.org/details/GeneralElectricSemiconductorDataHandbook1977

1977 is a maybe a bit too late?

[Edit:  on (printed) page 152 there is table similar to the one I posted earlier.   It shows configuration D as a "doubler" with two diodes.   The "packages" are different but none match you package.   So basically similar info but not quite enough to decipher you part.

On (printed) page 164 it mentions to contact GE for info.]
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 23, 2019, 02:28:59 AM
far @#$%in out ;)

thats a nice find. yeah, could call ge but i bet they'll be no help literally 50 years out.

i'm gonna check that archive link.

on the ebay link i think i posted for the one identical to the one i have here, or almost...
if ya look on the back, it lists all kinds of replacement numbers for different appliances, but i don't think its worth going thru all that nitemare to try and match it up if a couple 1n914's will work. ;)

lazy tonite. all i did was epoxy the broken mount back to the chassis, crazy glue'd first to get it to stay put, then hit it with the goo. its nice and solid now.
while watching it dry, i whittled a bigger hole in a very botched les paul  for a middle pickup i found somewhere. i did not do it. ;)
they really buggered this poor thing up. a couple hours with a couple files later, i can fit a humbucker in the damn hole and have room for the pickup rings as long as its an open coil one. i gotta box of buckers, i'll just throw some in.

ya play thru as much fuzz as i do, ya discover them cheap ones got one hell of a sound, a lot closer to the days of yore all the tonehounds with the 22k pickups supposedly pine for ;)

anyways, also gotta proper neutrik 6 pin din plug for the footswitch, the pos plastic one on got on ebay is already falling apart from the weight of the cable, lol.

oyyyyyyyyyy

anyways.. 2:28 been up since this mornin at 7 after gettin home last nite at 2:30 so i'm beat.

peace out and have a pleasant tomorrow, tonite, or whatever it is wherever you may be ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 23, 2019, 05:21:46 PM
Quote
but i bet they'll be no help literally 50 years out.
2019: I'm phoning about a rectifier ... What problem do you want rectify? ...
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 23, 2019, 10:34:16 PM
youu cain't get theyah, from heeyahh....

took the nite off finished tom/electric druid's flangealicious. very yummy.

i DID however, tho i forgot to measure that diode <and may have lost it in the debris field in the dungeon> remember to pull the tuner board out of the ovation. i'll scan both sides of it and try and write in the values tomorrow morn....err afternoon when i wake up.
i did check my notes, and other than the actual "on/off" switch and polarity reversal stuff, we got everything documented except for what bulb types and #'s for the strobe tuner and the pilot light. they're both incandescent. we're real close to being done with it i think, so i can finally button it up. i'm dieing to try it live. and its taking up serious bench estate!!
lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 24, 2019, 01:37:12 PM
ok rob,
here's the strobe tuner board.
PLEASE let me know if ya think there's any other data we need, i'd love to get this
behemoth off my bench ;)


(https://i.postimg.cc/563fdCWC/ovation-tuner-board-comps.png) (https://postimg.cc/563fdCWC)

(https://i.postimg.cc/zyG8JGqP/ovation-tuner-board-trace.png) (https://postimg.cc/zyG8JGqP)


this sucker is just about ready to sink a fork in ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 24, 2019, 03:55:12 PM
Quote
ok rob,
here's the strobe tuner board.
PLEASE let me know if ya think there's any other data we need, i'd love to get this
behemoth off my bench
Wow, awesome.   I think the unknown transistors are female, they have little skirts.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 24, 2019, 06:10:58 PM
hahah yeah little blue transistor spacers, not even sockets... and burkas made of epoxy ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 24, 2019, 07:15:23 PM
Quote
hahah yeah little blue transistor spacers, not even sockets... and burkas made of epoxy
A lot of old equipment had those things.  They come in various colors - for different occasions  :icon_mrgreen:.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 24, 2019, 07:52:50 PM
i thought they were sockets at first, but....
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on February 24, 2019, 08:25:03 PM
Quote
i thought they were sockets at first, but....
I've always understood they improve reliability when you have shock and vibration.   Not sure how well they work since if you don't glue everything the transistor can still move away from the PCB.   For TO-5 & TO-18 packages it can stop the metal can pushing all the way down onto the PCB and shorting on something.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 24, 2019, 11:33:45 PM
hahahah maybe they're so them stoned ass techs could line up the tabs on the q's so they'd install right ;)

hahah.... man, gonna be good to put this thing back together again ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on February 28, 2019, 02:12:38 AM
c/p from the fuzz ovation thread...

this thing is the weirdest freekin circuit i've ever freekin seen.

its had me and rob strand scratching our heads for weeks trying to understand how some of the stuff in the preamp this was lifted from can even work. seriously.

anyways, i was dicking around with it tonite and decided the 50k pot gotta go. its just not worth freekin' being there, its more of a damn switch for all intents, and doesn't really affect the tone enough to merit keeping.

that said,...
an
A500k pot is almost kinda cool, if you wire it as a variable resistance with just 1 lug and the wiper... as you mess with the resistance, there's spots in the sweep where it acts like a compressor, and squashes your attack and then swells in... depending on the transistors you used. very sick. not super great sounding, but ok for some sick leads, and not annoying if the piss flanged out of.

i ditched that pot entirely. i also found i liked a diode clipper at the end of the circuit, with a bat41, cathode to ground, and a 1n60ge with anode to ground. loses some volume, but gets a nice squishy overdrivey sound thats really tough to beat. especially when ya read this next part...

this was designed to be a parallel fuzztone with a preamped signal. weird, right?

i'm seriously wondering, after messing with this for weeks if they were freekin high on acid, geniuses, morons, or what... cuz in the original unit it phases against the signal and gets a fairly wide range of sounds.

this thing is WEIRD. i thought it was supposed to be a pnp in q2 and an npn in q1... but i somehow got that backwards. i think. sorta. i don't understand this @#$%ing thing AT ALL and it makes no sense whatsoever to me.

but i've got it running now, and sounding like a nice old-school overdrive/fuzz

for q1,
2n2905A.... pnp, si
https://www.onsemi.com/pub/Collateral/2N2905A-D.PDF
ready?

hfe 166
uF 663mv

reverse beta... c to ground
voltages, 9.26v b+
e  1.54
b   .70
c   0.0


q2, 2n5088 , npn, si
hFE 522 <close to the original bc109 in the original unit>
uF 672mv

ALSO reverse beta, c to ground
e 1.95
b   .57
c  0.0

gives a really nice, warm fuzzy overdrive with much more common parts.

this is a really weird circuit. i will try and get video of it soon.

anyways.. thats the update for now. i'll try n re-jig the layout and schematic accordingly.

i'd love to hear thoughts on why the hell this thing would be so completely different from the original unit, which had two bc109e's and .001u caps other than the 330n input cap... and it sounded like utter ass.

i'm gonna have to reopen the dang headpiece and try the different transistors out and see if it suddenly comes to life like it did tonite messing with it.

peace.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on March 02, 2019, 04:00:47 PM
FYI, I've been trying to finish other stuff off so I haven't had a chance to go over the tuner.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on March 02, 2019, 09:23:39 PM
i think i'm gonna pop it back open and try different transistors on the fuzz, see if it makes an improvement like it did on the standalone.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on March 14, 2019, 05:26:26 PM
hey Rob,
did ya ever get the tuner part drawn up?
;)

gonna go change the q's in it to what i reccomended above, and see if it brings it to life a bit more. stay tuned bro!!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on March 14, 2019, 06:14:40 PM
Quote
hey Rob,
did ya ever get the tuner part drawn up?
I haven't forgot.  I'm waiting for a chunk of time where I can do it in one hit.
ATM, I'm just cleaning up stuff in small dribs and drabs.
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on March 14, 2019, 06:58:15 PM
i feel that!
i actually could see the surface of my bench. for like, a couple hours. noddanymore lol
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on March 21, 2019, 02:59:26 AM
OK I finally got around to doing the Tuner.

I found a few issues which I've highlighted under "Unknowns" on the schematic.  In addition to those notes,
- There was one resistor without value on you parts value markup (R7) which I could derive from the other values.
- The value of R20 (47R) was marked as 98R. I'm pretty sure this is 47R.
- I've also guessed/calculated the value of the Trimpot RV2.

Under the "Unknown" section on the schematic:
- Looking at your first and second revision wiring notes, when I look at the white wire on SW1b it looks like the PSU is getting switched into the Top Boost switch.  This doesn't make sense.   Unfortunately I can't unravel where it should go since it kind of makes sense as is. 
- There's also some ambiguity with the Brown wire on SW1a and the Lamp Brown wire.

These aren't big issues but there's something a bit weird going on there.

Anyway here's the schematic and the part designators for the Tuner:

(https://i.postimg.cc/Rqk08BZN/Ovation-K6001-6ofx-Tuner-Board.png) (https://postimg.cc/Rqk08BZN)

(https://i.postimg.cc/BjgQXPcK/Part-Designators-Tuner-Board-top-view-xray.png) (https://postimg.cc/BjgQXPcK)

If you want to go over it to check it, or you (or anyone else) sees anything wrong please post the problems and I'll fix it.

Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on March 22, 2019, 10:17:44 PM
hey rob,
looks good man!
i will check my notes when i get a chance to see where stuff went, i believe the tuner on switch only has them two connections, and it definitely goes to channel 2 pin 10 i remember that. but i will check as soon as i can. kinda a busy weekend, so please bear with me!! ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on March 22, 2019, 10:55:18 PM
Quote
i will check my notes when i get a chance to see where stuff went, i believe the tuner on switch only has them two connections, and it definitely goes to channel 2 pin 10 i remember that. but i will check as soon as i can. kinda a busy weekend, so please bear with me!!
Cool, see how you go. I struggled with those parts a bit.

The way I understood it is Tuner #6 (Gray) goes to Channel 2 #4.  So basically that's the E tone passing to the input of of channel 2 - so you hear the tuner tone in channel 2; as per the manual.

The other connection is Tuner #10 which is the signal from Channel 1.  So what that does is feed a signal tapped of channel 1 into the tuner so you can use silent tuning using the tuning lamp light; again as per the manual.

I was thinking either Tuning #6 or Tuner #10 could go through the switch to isolate the tuner from the channels. However, since one side of the switch kills the power to the tuner it will probably work without switching those signals out.    When I look at the switches I can't see any switching of either of those signal (but that could be me misunderstanding some detail).

What I see on the tune switch is one side switching power to the tuner (Sw1a as shown).   However I'm puzzled where Sw1b goes!  It does go somewhere!
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: pinkjimiphoton on March 23, 2019, 01:47:46 AM
yessir, i guess i gotta take the mofo apart again. i wanna update the fuzz section anyways and see if it will work in the unit like the standalone does.

may take a couple days ;)
Title: Re: ovation fuzz from the late 60's/// help me resurrect it?
Post by: Rob Strand on March 23, 2019, 06:48:11 PM
Quote
yessir, i guess i gotta take the mofo apart again. i wanna update the fuzz section anyways and see if it will work in the unit like the standalone does.

may take a couple days
OK see how far you get.  I might have another look at you old wiring doc, new/revised wiring docs and the pics again.  I'm pretty sure I can't work it out since a couple of things didn't agree.