Weird issue with a Fuzz Face circuit

[hooya]

First off, this isn't my first rodeo.  I've made several dozen successful pedals, all of them more complicated than a simple Fuzz Face.  Most of them aren't dirt pedals though, and most of the dirt pedals I've made are Op-Amp based, not transistor.  Needless to say, I've got experiencing debugging complicated circuits (Meatball) but this one boggles me.  I can verify that the circuitboard doesn't have any bridged connections or missing any, I've gone over that more than anything else.

I'm using the Pelusa Face layout, etched myself, using the components suggested on the layout except for the transistors.  I'm trying to build this NPN using NPN silicon transistors (tried a variety).  For whatever reason, even using the Negative Ground version of the layout with NPN transistors the circuit is dead silent when powered.  Signal passes when the ground is disconnected on the circuit though.  If I connect the ground it sounds like I'm shorting the signal to ground.  If I power the circuit in reverse (switch the power connectors on the battery) it works somewhat, but I can hear my transistors die within a minute or so.  I've only done this once.  ;-)  I have tried TN3904, 2N5088 and 2N5457 but only got any results with the 3904.  I've flipped all of the transistors around on the layout (checking the pinout as needed) but no real luck there.

What the heck is going on here?  Can I not really use this layout with NPN transistors when selecting negative ground?  Why would it work when I send +9v to the ground of the circuit?

Any ideas?

[Quackzed]

that shem looks off to me, actually. it looks like the polarity isnt reversed for the ground connections, i dont think it will work as intended the way it is shown...

there are lots of other npn fuzz face schems to check polarity, but negative battery connects to ground, and positive, between the 330 and the 33k at the top.

[hooya]

OK, that schematic is way more straight forward than the Pelusa Face one.  I'm going to get a perf board from Radio Shack tomorrow and build based on that schematic (which might as well be a layout it's so simple).  Hell, I might even P2P it.

[PRR]

> I can hear my transistors die within a minute or so.

These circuit values and these voltages, you transistors won't die.

If the circuit is right, and you reverse the polarity, it usually won't work.

The fact that it "does work", then craps-out, suggests your electrolytic caps are unhappy about the polarity.

Circuit posted by Gil is correct for polarity and wil fuzz.

[hooya]

Interesting.

I just wired up this circuit P2P and it well... sorta works.  I really have to drive the crap out of it.  Probably one of the caps is fried then, since I re-used them.

I'll swap them tomorrow.

[Quackzed]

am i right about the schematic being half polarity reversed ?...


http://www.tonepad.com/getFile.asp?id=82


take a look...if so, maybee we should give tonepad a heads up?

[rousejeremy]

I built a Germanium Fuzz using the tonepad layout and my own etching. It looks weird, but it's right. You just have to let your eyes adjust.
As for the circuit muting when you connect the ground, try different jacks. You never know.

[deadastronaut]

hi guys...is that fuzz schematic above ok then?..looks nice n simple...still getting my head round schematics...

i want to build a fuzz for a bass....so using that schematic should i change the input cap to a 4.7 uf..and the out put cap to 100nf yes?...

going by the bazz fuss schematic ?...(which sounded too buzzy for my tastes)

what do you guys think...would that work? ive got a few of bc108s.......

is it tip negative?....

chees rob.

[Quackzed]

o.k. i think i see, the tonepad negative ground schem is for using negative ground with pnp trannies not npn.
so the tonepad schems are both for pnp transistors. not for npns and npns wont work in either the pos or neg versions.
the npn silicon should work with npn transistors. q2's collector resistor may need adjusting for best sound.
and  yeah, a bigger in cap and out cap will let more bass in...but may sound buzzy as well, the bass has a big signal and will drive the fuzz harder than a guitar would, but you can turn down the fuzz...

[hooya]

That totally makes sense. I'm planning to start fresh with this tough and will let you know how it works out.  Thanks so much!

[deadastronaut]

o.k. i think i see, the tonepad negative ground schem is for using negative ground with pnp trannies not npn.
so the tonepad schems are both for pnp transistors. not for npns and npns wont work in either the pos or neg versions.
the npn silicon should work with npn transistors. q2's collector resistor may need adjusting for best sound.
and  yeah, a bigger in cap and out cap will let more bass in...but may sound buzzy as well, the bass has a big signal and will drive the fuzz harder than a guitar would, but you can turn down the fuzz...

thanks quackzed...cool ,so the schematic is ok then....

if using pnp trannies...

and maybe a trim on the q2 collector instead?...

cheers rob.

[tiges_ tendres]

Interesting.

I just wired up this circuit P2P and it well... sorta works.  I really have to drive the crap out of it.  Probably one of the caps is fried then, since I re-used them.

I'll swap them tomorrow.

When you say drive the crap out of it, do you mean hit the strings really hard?  If so, your circuit is misbiased.  Could you post your voltages?