[sdiy] distortion pedal for a modular system

Graheme Wilson barkleycal at gmail.com
Wed May 2 17:21:15 CEST 2018

The Fuzz Face and similar pedals were designed for a speaker cabinet, 
this is why a Fuzz Face often sounds like a fizz face without a cabinet. 
I have a built a lot of distortion pedals including many variations of 
the Fuzz Face, it is a great economical design.

One way you might use it is like Jan Hammer did, plug your synth into a 
Marshall 100 watt stack with two 4 x12 cabinets,mike it up, crank up the 
amp and stand well clear.

In summary the Fuzz Face needs to be able to move some air.


On 02/05/18 09:27, stepan kayukov wrote:
> Hello everyone,
> Thank you for the lively thread.
> I have tried placing the FET in series with the capacitor. R7 connects 
> to the source - and C1 is connected to the drain (and then ground.)
> This tames the circuit a great deal, but the bleed is still very much 
> there.
> As for placing a capacitor between the collector of R2 and the first 
> op amp... I realize I drew it wrong in Eagle. This is the "basic" fuzz 
> circuit that I built, before sending to op amps:
> http://fuzzcentral.ssguitar.com/fuzzface/fuzzfacepnpschematic.gif
> So, the output from the transistor does pass through a 0.01uF 
> capacitor before going to the op amp.
> Still, the problem continues. It sounds like many people have had 
> similar experiences bringing distortion into a modular setup. Can it 
> be done? I am hesitant to build a separate power supply just to power 
> distortion modules.
> On Tue, May 1, 2018 at 6:03 PM, Tom Wiltshire <tom at electricdruid.net 
> <mailto:tom at electricdruid.net>> wrote:
>     I was interested to read your experiences with that module,
>     Quincas, since I had a hand in the design. I did some of the
>     voltage-controlled elements, including the tone control. Later on
>     it got an extra gain stage stuck on the front (to use up a spare
>     op-amp, IIRC!) and that probably does make it noisy. To be fair,
>     the original pedals aren't exactly quiet either.
>     Tom
>     ==================
>            Electric Druid
>     Synth & Stompbox DIY
>     ==================
>>     On 1 May 2018, at 17:52, Quincas Moreira <quincas at gmail.com
>>     <mailto:quincas at gmail.com>> wrote:
>>     The Frequency Central Meth Amp module I build recently is
>>     basically a Big Muff adapted to modular, and it is prone to the
>>     same bleed through problem.  I found that it is worse on some
>>     PSUs than others. In My Arturia Rackbrute it is silent, in my
>>     LM317/337 based linear supply it picks up all of my VCOs a lot. 
>>     My solution was to give it's very own small PSU, a little
>>     meanwell DC DC converter. However,  I suspect that sub regulating
>>     the 12v to 9v solves two problems:  It adapts the design without
>>     any component value changes, AND isolates the circuit somewhat
>>     from the main PSU. I have yet to try this myself but I think it's
>>     worth a try.
>>     On Tue, May 1, 2018 at 8:59 AM, Walker Shurlds
>>     <walkershurlds at gmail.com <mailto:walkershurlds at gmail.com>> wrote:
>>>         On May 1, 2018 1:28 AM, stepan kayukov
>>>         <stepan.kayukov at gmail.com <mailto:stepan.kayukov at gmail.com>>
>>>         wrote:
>>>             Hi Walker,
>>>             Thank you for the advice. It definitely sounds different
>>>             than it would on a guitar, but I still like it. The real
>>>             problem arises from hearing things at the output of the
>>>             distortion, even when nothing is at the input.
>>>             The R7/C1 distortion and the way the JFET is coupled
>>>             created a kind of gating effect that I was fond of, but
>>>             if you think it might be the reason for the overall
>>>             bleeding, I should try it the more conventional way.
>>>             Both of your suggestions are very helpful. I will try
>>>             them immediately. Since I am new to this list, I do not
>>>             know if I should post afterwards. Should I give an update?
>>         Yes, please update us! I think even if you leave C1 and Q3 as
>>         they are, but add some small resistance in that branch
>>         between C1 and R7 it could reduce the gain just enough to
>>         reduce the noise. Another thing you could try is increasing
>>         R8. There should be a value high enough that Q1 gets biased
>>         all the way off---this changes the sound pretty drastically
>>         (sounds kind of 8-bit) but makes it completely silent when
>>         there's no input.
>>         On May 1, 2018, 8:35 AM -0500, Joe Frey <frey at radioles.com
>>         <mailto:frey at radioles.com>>, wrote:
>>>         The best distortion pedal(and I have built several) I ever
>>>         built is the harmonic percolator. You can get the PCB layout
>>>         and build info if you search pepper spray distortion. Be
>>>         advised that one of the transistors connections are listed
>>>         backwards. I used components for the original version, not
>>>         the Steve Albini version. JoeF.
>>         I made one of the Tim Escobedo all-silicon version (but added
>>         the diodes back in switchable) and it sounds pretty great
>>         with synth. This would be a pretty good candidate for a
>>         module since the "harmonics" knob is just an attenuator.
>>         _______________________________________________
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>>     -- 
>>     Quincas Moreira
>>     Test Pilot at VBrazil Modular
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