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What I've got now is the GGG schematic posted above, except for I've changed the 2nd 4u7 cap to 10uF and added an external pot for bias.

*Question- I have one small issue and it's been happening since I first built this as a Supa... when I stomp the switch there is a slight delay before the fuzz comes out. I've never had that with any of my builds before. What did I do wrong? I'm not using a pulldown resistor or anything - should I be?

A lot of the old Tone Bender schematics are wrong, but close enough. It's hard to really pin point a go to schemo as the variants were so minor. There just wasn't the info back then as there is now.

No there shouldn't be a delay, how did you wire your switch?

Switch is wired like so-
http://www.generalguitargadgets.com/pdf ... gi_bat.pdf

So it turns out the issue was likely because I used a negative ground PNP layout. So it was decided that I should reverse the 3 electrolytic caps and then switch it to positive ground. I did so and now it has extremely low output. No fuzz, just very very low clean output. almost can't hear anything at all even with volume and fuzz knobs cranked full blast.

Do I need to switch the collector and emitter legs of the transistors around too? Please advise. I don't want to ruin them.

JVanDe7 wrote:So it turns out the issue was likely because I used a negative ground PNP layout. So it was decided that I should reverse the 3 electrolytic caps and then switch it to positive ground. I did so and now it has extremely low output. No fuzz, just very very low clean output. almost can't hear anything at all even with volume and fuzz knobs cranked full blast.

Do I need to switch the collector and emitter legs of the transistors around too? Please advise. I don't want to ruin them.

I don't know exactly what you did to make a pnp negative ground before, but now you are just wiring exactly the same as the schematic you referred to earlier.



2 of the elctro +'s go to ground and 1 to the input. Q1/2 emitter go to ground and Q3 emitter to 100k/1K attack

if you changed from npn to pnp or vice-versa, the electros would flip, the battery would flip and nothing else

good luck

Alright. All I did was flip the electrolytics and the red/black from battery (and the LED/resistor). I touched nothing else. Not sure what the issue is here but I guess I'll have to fiddle with it for a bit and try to figure that out. Maybe I overheated a cap? Worst case, I'll just build it again with a different layout.

Did you double check everything to the schematic? Flipping stuff leaves for a good margin of error. That vero layout is a mindfuck to look at. Print that schematic out, and go over it with a highlighter making sure you got everything orientated right.

Yeah that layout is a mess. I thought it would be great since it's so small, and it does get a few points for that, but aside from that, the layout should be scrapped. The fuzz and volume are shown wired backwards, the negative ground causes problems with PNP transistors (seemingly), and it's not easy to work with since everything is right on top of each other. Sorry I don't mean to bitch so much, especially since I'm not even skilled enough to produce a layout myself, but I really screwed up when I decided to use that thing.

I've already decided to just do it right and redo the whole thing using this layout instead... (probably won't get around to it until the weekend but we'll see, having too much fun playing with my V846 wah I built last night)

Be careful. Your -9V wire should be black and the +veGround should be red and make sure you follow the POSITVE ground wiring layout from GGG.

Thanks man. Good lookin' out. Despite my moronic posts here (haha) I'm actually fairly competent. I have several positive ground pedals that I've built. I do appreciate all of your wisdom and warnings and whatnot though - thank you. I'll be careful and it'll turn out fine. I think I can salvage most of the components from the old board. I have plenty of resistors so I'm not worried about those so much. I may have to track down a .1uF axial film cap though. And maybe a 4u7 axial electrolytic. I also think I might skip the transistor sockets this time. They add height to the board which is bad for business - small enclosure, tight fit. And I don't see myself experimenting with different trannies. I have but one or two laying around.

The new board solved it. So now I'm back to a Sola Sound MKII and not a Supa Fuzz at all. Sorry for posting it in this thread but I wanted to tell the conclusion to my Supa Fuzz adventure/build. I used all the stock values shown on this layout...
http://tagboardeffects.blogspot.com/201 ... ional.html
The only mod I did is use a 50K external pot instead of the 100k resistor on Q2c (bias control). Sounds great! Not a Supa Fuzz though.

JVanDe7 wrote:Not a Supa Fuzz though.

Not the Marshall made variant. That layout is based on an OCC81D Tone Bender MKII/Marshall Supa Fuzz. See page 3 of this thread for details.

Right on. So I don't even have to change the labels...

Bumping an old thread ......

A few months ago I got a bunch of really old pedals in for repair from an old guy that had most of them since the early 70's, and one of them was a Marshall Supa Fuzz with OC75's.

So here's a few pics













It had been repaired before, jacks and pots replaced, but everything else looked original.
I took a few voltages and also popped the transistors out and tested them using the RG method.

Battery 9.45v
Q1 - Hfe 67, Leak 241uA
C -8.61
B -0.043
E 0

Q2 0 Hfe 55, Leak 224uA
C -0.113
B -0.074
E 0

Q3 Hfe 52, Leak 177uA
C -9.39
B -0.115
E -0.174

I reckon changing the bias for Q3 would have made it sound better, or even changing it for a higher gain OC75 may have helped.

It still sounded cool.

and no, he wouldn't sell it to me.

Those hfes are quite low.. interesting.
Q3C sure is on the high side! Bet it was loud as fuck.
What does it sound like?

Hey EW, sorry for the delay in replying.

It actually didn't sound that loud, and it was quite a smooth fuzz sound, not in your face, not like any of the tonebenders I've built, but then again, I always use a higher gain transistor for the final stage. Also the owner was never over impressed with it over the years he used it. he said he always wondered what all the hype was about it. Still, I offered to buy it from him, but he wan't selling it.

Off topic and not related to Supa Fuzz.......

here's another pedal I fixed at the same time....... this got run over by a van after falling out while loading gear after a gig, can you guess what it is

Quite an early Rangemaster!

Q3's hfe could have been the problem, but it's a myth that it needs to be higher than Q1's and Q2's.
With three hfes and three leakages, a MKII is a rather complex thing with six variables. It's not always easy to figure out which variable you need to change to make it sound better.

Sweet, these are definitely my favorite Fuzz.
I have some metal can Ge PNP's with low hfe like that, with a bias pot they can be dialed in to sound great.

The circuit is not all that picky about hfe range. Leakage is far more important.