A somewhat different fuzz

[Pojo]

I like the abbreviation for this project....capslock and one swipe against the left side of the keyboard: ASDF 

[Gus]

Built the circuit and tested it with a J bass
I used a 1meg gain control
.47uf for C1
two 1n4148 diodes for clipping with a 10k in series with the diodes and C7
removed R2 and R10 and grounded the emitters
added a diode and cap at the DC supply

Bump
anyone build it?

[pinkjimiphoton]

got this one and the new buffer to boost in the pile bro.
been real busy with some fuzzes... like, 6 or 7 new ones this week... new to ME anyways.

hoping to get to this soon... so much to do so little time.

i DO seem to remember building this or laying it out, but damned if i can find it!!

[pinkjimiphoton]

hey gus, here's a vero that should be good to go. rudimentary power supply filter added to make it happier with a wart.

thinking it may sound good to have a diode clipper on the output for more of a boost..
will try and get on it soon. at least it's drawn up finally.

edit: helps if i remember the dang pic, eh?

[pinkjimiphoton]

edited .... there's a fine line between clever and stupid...

[pinkjimiphoton]

edit:

is this better gus?

[mac]

Sounds good to me, anyone else build it?

I built something very similar.
The major differences are:
- the first silicon is a low gain device, 2SC1213, hfe:130, no R3.
- both emiters are grounded.
- second stage 470k resistor is splitted in two 220k with a 33n cap from the junction to ground to have more gain, switcheable.
- BMP gain pot.
- no input resistor and smaller input cap, 33n, less bassy.
- 100p roll off caps

Except for the input cap, I bet that Gus and mine sound really, really close.
I highly recommend this one, very sweet sounding.
Think of it as a Small Muff Pi, or boosted Bazz Fuss 

mac

[pinkjimiphoton]

last vero i posted on the thread is built and running. used exactly what you posted, does sound nice.
fired up right away. it is kinda noisy, probably cuz it's not boxed.
very nice rich distortion tho i'd like it a little gainier if possible.
also tried (of course) germanium. ge x 2 sounded like poo, but a random ac176 or three i threw in there sounded great as q1 and most of the noise went away.
i'll probably make it so q1 is switchable between ge and si.
added one 1n4001 for polarity protection and a 100u filter cap.
the 100r resistor trick on the b+ would probably help with some of the little bits of hash.
also added 10r e to ground resistors instead of grounding them.
you got me in that habit gus.

nice project brother, thanks!! i'll try and shoot some video before i mutate it.

i'm thinking a single ge diode between the junction of the diode clippers and q2 c will help the noise and make it a little warmer.

i really like the tone. well done!

mac's right, it does sound like  that... maybe small muff pi  or a big bazz fuss pi

[pinkjimiphoton]

i just messed with this a whole bunch. i'm gonna make it so there's a switch for both transistors, ge on one side and 5089's on the other.

if it's too brite, try a 50k output pot instead of 100. warms it up nicely.

the gain control can go down to 100k and you get a real nice sweep but lose a little distortion.. but also makes it quieter.

really nice circuit. i am really digging your gain control gus. this is very cool!!!

tried gain pots from 10k-1m. 1m gives probably the most pronounced distortion. i bet 250 or 500k would be perfect if you're up to tinkering a little.

[Gus]

This is what I built

[mac]

I wonder if R20, D1 and D2 are similar to a pair of Leds or 4 x 1N4148 without R20...

mac

[pinkjimiphoton]

i went back in and played with this some more, decided to just stay with the 89's. not enough difference tonally really, but the 89's are a good deal louder.

and i like that.

[mac]

Jimi,
I bet that high gain AC187 can work fine, +200 or so.
I posted long ago a trick to put a Germ in a BMP without changing bias: just replace the 100 ohm resistor with a silicon diode.
This way the 100k will see the same voltage drop, and the diode resistance will be of some tens or hundreds of ohms.
If you need more gain bypass the diode with a big cap.
AC187 might need a smaller roll off cap or none at all.

or a big bazz fuss pi Wink

mac

[pinkjimiphoton]

i like that trick... i actually did it on the toneblaster project, i think it was.

thanks for explaining it to me! 

[Gus]

Have you had a chance to try it with a passive bass?

[pinkjimiphoton]

naaah, my bass is buried at the moment in the guitar chamber (26 of 'em stuffed behind my recliner and the only one i can get at without moving a bunch of stuff is my late wife's longhorn. probably sound good, i bet with lipsticktubes.

been hung up debugging another project. found a mistake on the schemo i think, trying to work it out. it's a little kay amp emu, all ge, very sweet sounding distortion that when working sounds ridiculousy like my kay 707 of my mis-spent youth. that beotch got loud at 4 ohms (supposed to be 16) with a kay fuzztone and a clone theory in front of it with a lpb 1 to overdrive it. too much fun.

[Gus]

I wonder if R20, D1 and D2 are similar to a pair of Leds or 4 x 1N4148 without R20...

mac

The 10K was selected for setting the 2nd stage gain when the diodes conduct
The .1uf was selected for the frequency the 10K and diodes can start to conduct, at lower values it will allow for more more bass level for the 2nd stage at lower frequencies before the diodes conduct
Both are tuning points for the circuit as well as the diodes used

I posted what I think is a good selection of parts I took into account
min and max gain
how the gain changes in both stages with the gain control setting
how the circuit clips
easy to find and standard value parts
no trimmers
The high and low pass frequencies

Other parts like the gain control (Jimi posted about this)are parts that can be adjusted
C1 the .47uf can be adjusted up and down in value along with the gain control
All of the cap values except the power supply filter cap will change the tone because you can change the high pass frequencies and low pass(C8) frequency

With all the points that can be adjusted it might be good to try this as posted before changing the values

[pinkjimiphoton]

in the end, other than the pot values (which i found worked best for me) the stock circuit is ace.

i mean... when the hell do i EVER use silicon transistors over germanium in something for me?

very toneful project as depicted. you CAN mess with it, but i don't think it's necessary. like, it's THAT good.

[Davelectro]

I think i'll need to build this one. Gain pot should be linear taper, right?

Now...

If Q1 were a low gain device, the emitter resistor could be smaller (10ohms) or taken out, and the clipping might be less symmetrical and more harmonic.

Gus, would you recommend trying a lower gain transistor for Q1 (think hfe 50-100) and smaller emitter resistance? I'm concerned about increased noise.

[pinkjimiphoton]

the gain pot, linear taper is great. used shielded cable and make sure the pot casing is connected to ground as well.
the output, you may wanna consider a reverse audio taper pot, it may give a better sweep from off to blast if you have one.
i'm betting you could go down as low as 10k on the output pot and it would work ok. i MAY have a defective pot tho, as i've run into a couple bad ones here and there.

fwiw, the 5089's i used were just pulled from the bag, i didn't really check 'em or anything, other than to make sure i got the pinout right with my checker (nice little digital multi meter with a decent transistor tester for like, 19 bux at harbor freight) but i do remember the first one was around 560hfe. to me, that's WICKED high for a fuzz to sound this good. the other could be higher or lower... i tend to be of the school i'll use random transistors, and see how it sounds before trying to tune it. and in this case, the original two were the best sounding.

i was really surprised at how much clean up i could get, and i just spent about an hour noodling on my semi hollow (the one in the video) thru it on various amp settings and really, really dug it.

it sounds kinda like a big muff a little... the way it breaks up is unique... but it's WAY smoother than a bmp, yet not as wooly as a fuzzface...but it responds like a fuzz face.

gus i think reinvented the klon right with two transistors. not the tone... but the idea of adjusting the gain stages like that. it's pretty cool.

lotta nuance... from smooth and sustainy to crystalline.... the highs aren't harsh, and the lows and mids are almost compressed.

my very favorite amp of all time was this univox i had for a while in the 70's. it had a cleanish compressed midrange, an explosive bass and a screaming distorted treble. this is kinda like that but not a bright.

i'm betting lower gain transistors in q1 will gain some upper harmonic content at the expense of some overall distortion. but there's a good amount of that on tap.

this DID sound pretty good with npn ge's, too ... switching a lower gain germanium with a sweeter quieter overdrive with a 5089 that's screaming could make a really nice footswitchable option.