"latest FF mod brief'

[petemoore]

Depends on so much I figure just put the 'brief' out here and see what FF tweekers think of them.
 Nothing really new except my interpretation here either.
 All these FF mods have values, here I'm just 'calling' them 'Small and Smaller'.
 Rolling off highs and how the highs are clipped is the focus.
 There are numerous ways to do this, I'm finding great results using 'smaller' caps in the known positions, but more of them sprinkled throughout the circuit.
 I'm not enough of an EE to understand how a HF rolloff cap across the ~470ohm [great mod on Axis Face] compared to across Q2's C/B connections, using smaller than specified in the Axis Face, in combination with a Q2C/B HF rolloff Cap [~.0022uf or less].
 It should be noted I'm the only one I know of who's used the 'sprinkled rolloff caps' method for smoothing an Si FF, so my finding it useful is quite subjective, but warrants mention.
 Also a cap marked 102 can be used 'anywhere S.P. to ground", including Q1 Base. Larger small values, or a .01uf>10kpot to ground at output can be used.
 All of this leads to the Angel Series [partially inspired by the AS] type FF,
placing a Mu amp after the FF.
 I have a wall warted, V/Regulated with LM317 power supplied Mu Amp [voltage drop knob], that sounds superb with a Mu amp of FF driving it.
 Tweeking the FF for use with the V/R'd Mu Amp [highs get accentuated by the Mu, maybe rolling off some of them in the FF] may help.
 Anyway, that's my circuit...makes for a very smooth toned muscular and flexible FF/Mu sound !!!
 You've heard me typing about that V/R'd Mu, THIS IS a great circuit to have around. It can be set many different ways, I've it set so single low notes 'bloom above', chords get squashed [when pushed to do so], single notes ring harmonics....VERY Nice.
 Besides the great tone and flexibilty of a Mu with MPF's to 458's in it [for L ower Gain or High Gain use], it lends itself perfectly to being voltage starved because the rest of the bias arrangement can remain 'static' [tweeking other bias R's isn't needed to maintian 'proper' bias under starved conditions]...you...somebody else besides me...needs to try this.
 I used a 2u2 across the B/G instead of the 3u3 in the Minibooster, {Thanks to Jack Orman for the great Minibooster !!! }this helps keep the bass from becoming loose with use of a pregain stage.

[WGTP]

Like you, I'm know EE, but I think that each time you add another cap to the circuit to roll of highs, you are creating a higher order low pass filter and possibley lowering the roll off point.   Sometimes I think I'm doing that when I'm inadvertantly paralleling the caps.

Mark Hammer has advocated using 2nd order filters for more effective fizz removal.  

In many of our multi-stage distortions we create high order high pass filters by using caps between stages.  Just a thought.  

1 - 6db/oct.
2 - 12db/oct.
3 - 18db/oct.
4 - 24db/oct.

[petemoore]

SincI don't really know...
 Rolling off highs at the input, anything that gets in/out of the circuit is rolled off including both sides of the waveform clipping, anything more than just a detectable touch of it here takes too much of the character from the Fuzz.
 Rolling off highs between Q1C/Q2B and ground hasn't been discussed much IIRC, I never tried that much.
 The ingenious Axis Face rolloff cap across the 470...[?'s]...in practice works great.
 Q2B/C rolloff cap, I like this one, not talked about much, I think it's good to combine this mod with the AF 470 mod, letting both positions share a smaller rolloff role [smaller values spread over 2 positions instead of 1].
 Output...I have a Ge FF with a seriesed .01uf/10k from SP to ground, but I think I like the caps 'inside' the circuit board for rolling off highs better.

[jmusser]

Pete, I've never actually built a Fuzz Face. I have built the hybrid Easy Face, but it seems like I've read on here before that a Fuzz Face really doesn't work to get the wooly Ge sound, unless you're playing through a tube amp. Can you shed any light on this? I kind of felt that was the down fall of my Tycho too, that it really needs a tube amp to shine.

[petemoore]

FF into SS amp...I'm not the one to recommend it or have suggestions for it...never had anything but unusable results, others report great tone[?]...
 Thays a million FF's, the one you like best is the one you know of to work best...finding the 'new' ones [to you] might be where it's at.
 I just put this up [the sprinkle cap thing] because that's one I'm liking...hopefully [because FF 'tunings' are, and should be IMO very subjective] your's is different and matches your equipment and needs.
 With 90% of the components of the FF, changing the value of one or adding another can fundamentally change it's response.

[MartyMart]

In my experience, FF --> Solid State amp = BAD sound
FF --> Valve amp, just starting to break up = Great sound

They can be little "Buggers" to get right, I have two that just won't do
"The sound" and two that are just perfect !  :shock:
I guess that there's some "mojo" going on, even if you have the "exact"
same layout/parts/transistors ( too a degree ) they are all going to be
different.
Some times you get lucky ..... but when you do  

Marty.

[brett]

Rolling off highs between Q1C/Q2B and ground hasn't been discussed much IIRC, I never tried that much.

Cool idea.  Because the output impedence from Q1 is fixed (ie the 33k resistor is more-or-less standard), it is easy to nominate a cap for this position.  0.001uF will give a cutoff frequency of 5kHz, which I find is about right.  IF you are going to combine this mod with the rolloff cap across the 470 ohm resistor, the filtering effect will be stronger, and the value should probably be lowered to 680pF (fc=7kHz)or 470pF (fc=10kHz).

The ingenious Axis Face rolloff cap across the 470...[?'s]...in practice works great.

Indeed it does.  I've been promoting that ever since I built Aron's Rocket (which has the mod).  Before that it might have come from Gus ??  To my ears it was better than the base-collector cap method, so I  passed it on to Philip.  

The mu boost is a VERY cool circuit and the idea of variable starving it is great.  I agree with the 3.3uF cap being too large.  Personally, I don't understand why it is so large when its series resistances are very large (megohms I *think*).  I've built it with a 0.1 uF, and it seemed to work fine.  

Do you have a schematic of your starved mu booster? (Gees I'm lazy sometimes!)

cheers

thanks Pete

[petemoore]

Yes but I haven't been able to get a link to it, tried for a time and will try again.
 It's in Express Schematic on this computer, and...I I'm a bit illiterate about how and what I need to convert it to gif and all that.
 I don't like to tell this story for fear of trying to be helped !!!
 People try to help me in vain, I don't know what programs I need to read up on...I don't know how you guys figure all that stuff out !
 I know once you get it it's probly easy...I suppose I need to try again soon.

[Coriolis]

Hmm...I've just deleted Express Schematic and Express PCB from my system for the same reasons: It seems that the only way the want you to be able to export anything, is to Express PCB themselves. Makes sense considering they want you to buy some pcb's, and not just drawing schematics and pcb layouts to share with others.

Only luck I've had was with taking a screenshot and pasting it in GIMP or another graphics program (Photoshop), then saving it to a GIF, PNG or JPEG.
That would work fine with a schematic, since size and scale isn't critical (with regards to printing) as it is with a pcb layout.

I'm actually building an FF (69 clone actually) right now, and it's my first, so I'm enjoying your tips and tricks a lot here! Thanks people!  

C

[brett]

Going OT a bit.

It seems that the only way the want you to be able to export anything, is to Express PCB themselves.

Not far wrong.
There IS a problem with screendumps (ie hitting the PrintScreen key and pasting into a graphics program).  With large schematics, shown all on one screen, the text can be substituted with stupid little boxes.  Arrghhhh!!!!
However, using the "Copy schematic to clipboard" option (under "Edit") works, keeping the detail.  
To manipulate and convert the image, open IrfanView or PhotoEditor or a similar graphics package and Paste it (PhotoEditor:"Paste as a new image") in there.  Usually there's a lot of empty white space in the image, but most packages have a "crop" option.  To convert the finished product to a .gif file, check out saving as a .gif file under "Save as" in the File menu.  
Although I use PhotoEditor at work because MS Office is our standard gear, at home I use Irfanview a lot.  It's free, it's a small download (essential for my 28.8k modem) and it offers more options than I'll ever need or understand.
cheers

[formerMember1]

about ff mods:
The roger mayer mods according to geofx, you know raise the 8.2k to a 18k and raise the 1k to a 2k and etc...  I never had any luck with that.  The pedal always was misbiased this way.  Anybody ever modify a FF and get it right with these mayer mods?  Did it sound like montery pop?

I don't know if i am reading the geofx site wrong, but right after the mayer mods it says about changing the input and output caps,  Is this part of the mayer mods or is that just a tip from R.G.  ?

thanks  

[brett]

Hi.
The JH mods definately work.
I *think* it was the first pedal I ever built.
It increases maximum gain a tad, with no adverse effects that I could detect (in the pedals sold with this circuit they also used high hFE transistors (MPSA18s I think) that ruined the effect).
have fun

[petemoore]

Two words for FF: Bread Board
 or these two: Trimpot, socket
 The insides of Q's can't be 'diddled' with, having a handful of these which are 'likely candidates' helps 'tip the odds'.
 Having about 3x the number of caps the FF uses makes it easier for You to voice it [various values, and these can be 'built' into other values too].
 Otherwise just use the schematic[s.
 I've gotten quite a lot of various responses's from FF's, built batches of them, and found 1 that I like best...again, it's very close to the Axis Face.

[formerMember1]

yeah, i am building the axis face and axis/vox wah now. ( I just got my halo and propot so far.  I heard great things about the axis face too.
yeah i gotta get a breadboard, i keep putting it off.  I am gonna try get a jameco in my area if not i'll order one.

also got sockets,

i ordered a lot of different values for the input and output caps. also trimpots.  

it just seemed that when i changed the dunlop fuzz to mayers mods it didn't sound right.  I used a pair of matched trannys off smallbear.  When i biased it my way, it was pretty good, but nothing great. Doesnt matter now though cuz i threw it out.  Just kept the enclosure.
same with my gcb-wah.(well actually used it for spare parts)


Once i find my desired values in the fuzz should i unsolder the sockets and solder the parts in, for reliability?  It seems you would get a better connection by soldering.

[petemoore]

I've been running SP through sockets for years, had not a problem with that once...except.
 Larger caps [like 224's] need to have a 4 pin socket for proper 'hold' if I bend the leads to fit in a 2 pin socket, the caps will tend to fall out :oops: .
 So my take is just leave the sockets in there. Pulling them out is difficult and tends to bridge solder across pads...no good. [not so bad if you have a 'center pad' [open pad[s between 2 soldery pads] that's not used.
 I just shake wiggle and find if a parts likely to fall out. I have pliers that flatten the tips of socketted leads, useful for cramming two leads into one socket pin, and pliers that put a 'catch' on leads to keep them in sockets. some use hot melt glue to hold the parts in.

[formerMember1]

cool thanks for the help,

I still might take out the sockets, cuz instead of soldering them tightly i will just use a third hand and barely stick them i their.  That way i could reheat it and pull them out.  I just don't like the idea that a part is connected by a socket.  I could see IC's but not transistors and caps and stuff.  thanks

[petemoore]

I always use sockets. I've never had a well placed transistor fall out, J201's I put the source on the 'bottom'. Whoops edit, it happened before the below methods were implimented, with heavy, tall NTE158.
 I like that I can swap Q's, especially in a FF, that way it can always be 'another' FF.
 That's just me, I cut, bend, *permeate [*straight tread plier jawgrip'] the transistor leads.
 I have had caps fall out.
 For WCScenarios like pedal drops, soldered in stuff will withstand these incidents to a greater degree, impossible to argue against the logic that follows this fact.

[formerMember1]

hey petemoore & other DIY's, :wink:

I was wondering something, i understand your method of using sockets, but i just don't feel comfortable using sockets in a "finished" pedal.  Since i am going to socket the input cap,trans, etc... in my fuzz, as well as socket the biasing R, vocal, input cap, Q1, Q2, etc... in my wah.  I was wondering if when i install my sockets , if i could take the plastic off of the sockets and solder them to the board, then when i finally figure out what "finished" values i am gonna use, i wonder if i could solder the caps,trans, etc... into the sockets?

summary:
Anyone know if i could leave the sockets in board and solder the parts in the sockets without any extra noise or capacitance etc...?

Or maybe when i am find my "set" parts, i should just take out the sockets.

thanks,

[petemoore]

well you found the questiong to which the answer is  :oops:
 Short answer is yes it can be done.
 Just doing one lead of a large cap is plenty nuff for me to believe the other end will stay in the cap,
 Pinning the plastic part of the socket to the board is what keeps the socket and part from swinging back and forth, the bend resistance of the socket wiper ribbons and board pads is reduced if the plastic part of the socket is eliminated...
 I've seen hot melt glue used over large caps, a glob going from top or side of the cap to the 'floor of the board isn't uncommon. This insures the cap will not come out until you want it to [I'm sure clean surfaces, reasonable temperatures, humidity and time notwithstanding], hot melt gloe seems to do the trick.

[formerMember1]

cool thanks,

but what do you mean:

well you found the questiong to which the answer is :oops:

*EDIT*
Never mind, i woke up in the middle of the night and realized what you meant,  :lol: