Next DIY Project: Fancy Fuzz Pedal

[Tone2TheBone]

Great information Voo thank you. I'll snail mail you some Radio Shark cheapo batteries to use in your box. As you know Fuzz Faces sound their best with those. Lots of great stuff here I totally enjoy your pedal project posts.

 

[luvmyshiner]

Very sweet Voodoo, keep inspiring us!

 

[mrmudcat]

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.

Oh no the gears in my brain started smoking and are clooging up trying to digest this tidbit of info .............wait its sinking in gears are moving again ......im OK......phew that was close to a full lockdown!!!!

 

[Tone2TheBone]

Oh no the gears in my brain started smoking and are clooging up trying to digest this tidbit of info .............wait its sinking in gears are moving again ......im OK......phew that was close to a full lockdown!!!!

Hey I heard that ole Skydog used to put his Fuzz Face inside a cooler because he felt it sounded better cold so you need to start paying more attention to this sort of stuff buddy.

 

[mrmudcat]

Oh if only you could see my batch of nearly dead batteries:beer: (based on the same mythical legend):bravo:

My wife thinks im crazy:rockon: But she always has:rotflmao:

 

[tot_Ou_tard]

Your opinion is duly noted. So you should paint yours green!

How do you know that he hasn't already.....

O! we're talking *pedals*!

Never mind.

I might have missed it, but why does the PNP germanium doodad force positive grounding?


Great project as usual Vood! I can't wait to hear the clips.

Are you gonna give us a blind vote on the different Ge/Si settings as you did with the Zonker?

 

[duhvoodooman]

I might have missed it, but why does the PNP germanium doodad force positive grounding?

Great project as usual Vood! I can't wait to hear the clips.

Are you gonna give us a blind vote on the different Ge/Si settings as you did with the Zonker?

As I understand it, employing PNP transistors doesn't force the use of positive grounding, but it is much less prone to complications and undesirable side effects that often pop up with their use in a negative ground circuit. The GGG site specifically mentions that they used to include a PNP/negative ground version of the FF clone project on their site but dropped it because so many people (the language used suggests that it was a majority of those who built it!) ran into problems, primarily oscillation when rolling back the guitar's volume knob. And since a popular feature of the Fuzz Face circuit is its ability clean up nicely when you back off on the volume a little bit, this was a really annoying problem. Why this happens, I couldn't tell you.

I hope to get a couple of clips recorded and posted this weekend. Will try to cover the four transistor combinations as part of that....

 

[Tone2TheBone]

Clips man we need clips. Oh you already said that. Cool.

 

[duhvoodooman]

Well, I still haven't gotten around to recording a clip or two to post here, but I did finish decaling & clearcoating the pedal, so it's officially "finished" now. I posted this pic in another thread, but seems like I should have a shot of it here, too, for the sake of completeness: