Next DIY Project: Fancy Fuzz Pedal

[duhvoodooman]

I've ordered parts to make a modified clone of the Fulltone '69. For those of you not familar with that boutique fuzz pedal, it's a take-off on the classic Dallas Arbiter Fuzz Face circuit, with a couple of extra controls. In addition to volume and fuzz knobs, the FT'69 also has a "contour" knob that dials in more or less mid-range, and a "bias" control that cleans up the bass, if it gets muddy/woofy sounding. I'm building it using the Fuzz Face circuit PCB available from General Guitar Gadgets ($9). Their site has the instructions/part lists for 5 different versions that can be built with the one PCB. The Fuzz Face is an amazingly simple design, so it was an easy task to source the needed components, and the other hardware (enclosure, jacks, switches, pots, etc.) are all things I've used for other pedal builds and for which I already had sourcing info.

The Fulltone '69, like many of the early Fuzz Face variants, used a pair of PNP germanium transistors for its characterisitc fuzz tone. This type of circuit construction gives you a "positive ground" pedal, unlike the vast majority of modern effects, which are almost always negative ground. You can still power a positive ground pedal with a typical AC 9V adapter....but not with any negative ground effects hooked to the same power source! So you either have to use a dedicated wall wart for it, or do what most people do--just run it on a 9V battery.

However, the ol' Voodoo Man isn't content to stop where the Fulltone '69 design leaves off! My version will incorporate two additional modifications:

• Switchable transistors--By wiring them up to two DPDT toggles, each transistor position on the PCB will be switchable between germanium and silicon types. Silicon transistors tend to give a somewhat louder and more aggressive fuzz tone than germanium. This dual-switching capability will give four different combinations for the series transistor pair: Ge/Ge, Si/Si, Ge/Si, and Si/Ge. This mod enables adjustment of the character of the fuzz tone, as well as its degree.
• Transistor voltage bias control--Since the two types of transistors have different gain characteristics, a voltage bias pot allows you to dial in the optimal voltage at the collector of the 2nd transistor, to adjust the pedal's fuzz tone. With the switchable transistor feature, I'd consider this an almost mandatory mod to include with it.

Attached below is my preliminary "mock-up" of the pedal's layout and graphics. I may have to alter this some, based upon the dimensions of the PCB and how much room is needed for the two transistor switches, but it should look pretty close to this when done.

I'll post more as the project progresses....

 

[tunghaichuan]

Looks like a cool project. :AOK: Keep us posted.

tung

 

[Robert]

You bastid. You know how to create G.A.S, don't you?

 

[marnold]

Will this be for your own personal use or would you be whipping a few of these bad-boys up? Methinks that a fuzz pedal would be the next one that I'm after. I can't find a decent one for less than bootik prices.

 

[duhvoodooman]

Will this be for your own personal use or would you be whipping a few of these bad-boys up? Methinks that a fuzz pedal would be the next one that I'm after. I can't find a decent one for less than bootik prices.

This one's for me, since I (rather incredibly!) don't have a fuzz pedal in my arsenal of tonal weaponry. Let me see how difficult/time-consuming the build is, before I answer the "commercial availability" question. The transistor switches are somewhat involved (a bunch of stuff in a small space), and there are a lot of wires running between the PCB and all those pots.

 

[kerc]

Funny, today I received two NTE158 transistors for a Fuzz Face clone I'm gonna build.



That looks like it's gonna be a very cool pedal, DVM!

 

[duhvoodooman]

Funny, today I received two NTE158 transistors for a Fuzz Face clone I'm gonna build.

Have they been pretested for the proper gain range, Kerc? Apparently, that is the key to a good germanium fuzz, because these transistors tend to be wildly variable in their gain and current leakage characteristics. Fulltone doesn't even make the '69 pedal any more, because they claim they can't get consistent germanium transistors in sufficient quantities.

I bought a pretested pair from Small Bear, one of GGG's two recommended sources for them. $15 for the pair--not cheap. Compare that to the silicon transistors, which were 25 cents each!

 

[warren0728]

um...with a "grow your own theme" maybe the pedal should be green... :whatever:

ww

 

[Adrian30]

That is going to be one great pedal, DVM. Keep us posted.

 

[warren0728]

This one's for me, since I (rather incredibly!) don't have a fuzz pedal in my arsenal of tonal weaponry. Let me see how difficult/time-consuming the build is, before I answer the "commercial availability" question. The transistor switches are somewhat involved (a bunch of stuff in a small space), and there are a lot of wires running between the PCB and all those pots.

speaking of "commercial availability" are you going to be making anymore zonkin yellow screamers?

ww

 

[duhvoodooman]

um...with a "grow your own theme" maybe the pedal should be green...

Nah, Fuzz Face clones are supposed to be bright red, like the original pedal. It's a tradition!

speaking of "commercial availability" are you going to be making anymore zonkin yellow screamers?

The problem there is that I used the BYOC "Overdrive" TS clone PCB as the basis for the ZYS. Unfortunately, Keith Vonderhulls (Mr. BYOC) is no longer selling the PCB's separately--just the full kits. So what used to be a $7 PCB purchase now requires a $90 kit purchase!! Though I could use many of the components in the kit for the build, it would raise my overall cost per pedal by over $60. Too much to pass through to a customer, IMO, when I'm already charging $200 for a ZYS.

There is an alternative, however. GGG sells a TS-clone PCB, which is essentially the same circuit. So I just need to go through my ZYS design, confirm that the essential features can all be built upon this different PCB, and then build one to prove it out. I'll need a "guinea pig" customer, though. Wanna volunteer, Warren? I'd knock a few bucks off on this first one. I'm not making any promises, until I check it out more closely, but it looks very doable to me at first glance. In any case, I wouldn't be undertaking it until I finish this project and a couple of amp mods I also just ordered parts for....

 

[warren0728]

I'll need a "guinea pig" customer, though. Wanna volunteer, Warren? I'd knock a few bucks off on this first one. I'm not making any promises, until I check it out more closely, but it looks very doable to me at first glance. In any case, I wouldn't be undertaking it until I finish this project and a couple of amp mods I also just ordered parts for....

i'd be interested....

ww

 

[sunvalleylaw]

Sounds like a cool project. I have been having fun playing with my EH Little Big Muff Pi Fuzz.

 

[Dreadman]

Cool thread. I only understand about every other word of the technical stuff but it's enlightening none the less.

DVM - If you ever have a need, I own a CNC machine shop and would be happy to extend a very friendly rate to you for forum project stuff (I love a good forum project). Drilling and/or engraving on cases, drilling and cutting blank copper clad boards........ Don't hesitate to ask.

 

[Kazz]

I agree with the nekkid pancake flipper....the pedal should be green.

 

[duhvoodooman]

I agree with the nekkid pancake flipper....the pedal should be green.

Your opinion is duly noted. So you should paint yours green, when you make one!

 

[mrmudcat]

:rotflmao: :master: :beer:

Raunchy red fuzz!!!...........cant wait for this one!!:AOK: :rockon:

 

[warren0728]

Nah, Fuzz Face clones are supposed to be bright red, like the original pedal. It's a tradition!

yeah but the tradition of "growing your own" is green :beer:

ww

 

[marnold]

yeah but the tradition of "growing your own" is green :beer:

Just to further this pointless debate, I agree with DVM on red. Plus, if I say that, he may be more likely to build me one

 

[sunvalleylaw]

Just to further this pointless debate, I agree with DVM on red. Plus, if I say that, he may be more likely to build me one

Seems like a custom Fuzz pedal should be the color of perhaps pocket lint, or maybe the stuff in your dryer's filter after a pajama load. Looks like it will be great DVM!

 

[warren0728]

Seems like a custom Fuzz pedal should be the color of perhaps pocket lint, or maybe the stuff in your dryer's filter after a pajama load. Looks like it will be great DVM!

:bravo: :rotflmao: yeah some contact spray glue and dryer lint and you really will have a fuzz pedal!!

ww

 

[duhvoodooman]

When exactly did I lose control of this thread?? :thwap:

 

[warren0728]

When exactly did I lose control of this thread?? :thwap:

i would say pretty much from the start.... :beer: :rotflmao: :thwap:

it will be a great pedal though i am sure....

ww :greenguitar:

 

[WackyT]

How 'bout that red fake fur contact cemented to the case?

 

[duhvoodooman]

Something like this, perhaps?

 

[Algonquin]

Something like this, perhaps?

That's really disturbing...

 

[Tone2TheBone]

Come on you guys Fuzz Faces and their clones have to be red!! Although the original Dallas Arbiters and reissues have been known to be primarily red, blue, gray with a couple of yellow ones and yup even one green one having been made but are owned by one guy who worked for Crest Audio back in the '80s when they made reissues. (the Foxrox Electronics dude).

 

[duhvoodooman]

Progress!!

Got the last of the parts on Monday and built the pedal the last 3 evenings. I used an enclosure predrilled for the jacks, LED and 3 knobs, and then added 4 more holes for the other two pots and the two switches. Next time, I'd buy the enclosure undrilled and add all the holes myself, because the predrilled hole positions forced me to crowd everything in up near the top and made the wiring a real PITA. Live & learn.

Anyway, here's a topside pic and a "gut shot". Only had a chance to check out basic functionality at very low volume (it was late last night when I finished it), so while everything works properly, I really don't know what it sounds like yet! This evening, we'll unleash the hounds! :rockon:

I still need to be decal & clearcoat it, and mount the AC adapter jack permanently, though this positive-ground design is really best suited to running on a battery....

 

[Tone2TheBone]

Wooooooo buddy that's lookin' good. Nice and fuzzy red. Good call you made on future undrilled enclosures. I know you used PNP transistors but I'm unclear as to how you'd wire for the negative ground adapter connection. I'm gonna wait patiently for those clips and final photos.

 

[duhvoodooman]

....I know you used PNP transistors but I'm unclear as to how you'd wire for the negative ground adapter connection.

Basically, for a positive ground pedal, you just have to think of the electrical flow as backwards through the pedal circuit. So any polar component on the PCB (e.g. electrolytic caps, diodes) have to be soldered in the reverse orientation. Then, when you wire in the battery or AC adapter jack, you attach the positive lead to the input jack ring and the negative lead to the 9V eyelet on the PCB--the exact opposite of how the vast majority of effect pedals are wired. Hence, the DC current flows in the opposite direction through the pedal circuit.

The cool part of this wiring method is that you can still use a standard negative-tip 9V effects adapter to power it; you just can't power any negative ground pedals from the same power adapter. If you do, the adapter shorts out (and may overheat or be damaged) and the effects attached to it won't work, though they won't be harmed by doing this. Alternatively, you could wire the AC adapter jack itself backwards, too, but then you'd need to run it with a positive-tip adapter.

I've read that there are ways to wire a negative ground circuit to use PNP transistors, but I understand these combinations often give oscillation problems and are best avoided. Apparently, GGG (where I got the PCB and all the instructions/diagrams for this fuzz pedal project) used to offer a negative ground PNP version of the pedal but no longer do because of the high frequency of problems with that combination.