Fuzz face / noise maker worries

[spule]

Hi- this is my first post here 

Recently I built an (almost) standard pnp fuzz face using AC151 - Here are the schematics (very similar to General Guitar Gadget's Boutique Fuzz Face) : http://img355.imageshack.us/img355/7465/noisemachinesa0.jpg

So- when I was trying out the circuit, I accidentally touched the bottom of the board with my fingers and the whole thing started to oscillate like mad! I found out that when points A or B (on the schematic) are connected to point C with a resistor of a larger value (or my fingers in this case  ) the oscillations start. I liked what I heard and I decided to incorporate that in my pedal. So here's the picture:



The board on the top is just an etched PCB and words "Fuzz" and "Noise" are connected to points A and B and "Machine" to point C from the schematics.

And now for the worries part:
This came to my mind (of course) after I boxed the whole thing up- Could this oscillations (which seem to be louder then the guitar signal) be harmful to my amp? And is there something wrong (electronically) with connecting these points in the circuit with a resistor - does this maybe damage the transistors?

And one more weird thing- when the pedal is bypassed I can still make the thing oscillate by touching the PCB, although it is much more silent..

So-what do you think?

[GREEN FUZ]

Dunno but it looks damn cool.

[spule]

Thanks!
It's my third build and I'm pretty happy how it turned out.. But the noise maker side of it is really worrying me.. 

Anyone?

[darron]

hmm.. i can't see any major issues. i may not be the best authority on this one. i also found this with a fuzz face when i used my finger and accidentally shorted between the input and another point.

using point A however will bypass that input cap by a tiny amount, which COULD let DC through into the circuit if the effect before it doesn't have a output coupling capacitor. i suppose points A and B sound a little bit different because of the voltage divider.

so you could just use the point b one, or to be ultra safe put a large value capacitor before the input and before point a?

hey.. could you please get some sound recordings? (: i forgot what that cool shorting sounded like and i never followed it up....

what happens when you play barefoot?

[spule]

Hmm.. So there IS something to worry about. Points A and B do react differently and I want to be able to use both, so I think I'll do as you say and use that large value cap and see how it works.

And as for the recordings- I don't have my camera at the moment, but as soon as I get it back, I'll make a clip.. Maybe even a barefooted one 

[yeeshkul]

I built a silicon FF and i noticed the same trouble - when i touched the second tranny with my finger it started oscillating like mad.

Oscillation can be sometimes caused by unwanted feedback from the collector of the second tranny to the base of the first tranny. That's why there is often resistor between the 33k resistor and the 25k pot (usually combined with a filtering capacitor between the voltage and the ground)