Fuzz Face question

[tcobretti]

I built my socket face and have been plugging and playing components like mad.  A really weird thing happened when I turned the electrolytic caps around - nothing changed.  Everybody says to go from PNP to NPN you have to change the caps' polarity, but as far as I can tell it doesn't make a difference.  What am I missing here?

[alderbody]

Everybody says to go from PNP to NPN you have to change the caps' polarity, but as far as I can tell it doesn't make a difference.  What am I missing here?

you also need to reverse the polarity of the power supply...

PNP -> positive ground
NPN -> negative ground

[brett]

nothing changed

Did the gain stay the same?  With the 22uF cap reversed I'd expect its capacitance and AC conductance to be diminished.  But maybe not?  Any loss of bass?

[mac]

With a max of 0.45 - 0.5V voltage drop across a reversed 22uf cap in a FF, can capacitance and ac conductance be altered to be appreciable??

mac

[Tamir]

By the way question, what another polarity actually gives us? what are the differences between PNP and NPN in sound? do we do it just because of the transistor type?

[tcobretti]

1) I do realize that you have to reverse the polarity of the power supply.  My point was that I didn't and it didn't make a difference with regard to the electrolytic caps' polarity.

2) There was no detectible change in the sound as long as the component was present in the pedal, regardless of polarity.

3) The only reason to build PNP vs NPN is that most Ge transistors are PNP. 

[Tamir]

thank you very much 

[tcobretti]

Does anyone have any ideas about my original question?

[R.G.]

The voltage across those caps is quite low.

An aluminum electro will withstand a slight reverse voltage for a while. Eventually it will fail, but it works for a while. Tantalum does this even better than aluminum.

[tcobretti]

Thanks RG.

[mac]

I heard of some people saying that pnp versions sound better, ie, www.pisotones.com in spanish. But how to compare Ge npn & pnp unless you use complementary transistors, ie, ac187 & ac188? And even if you get complementary ones, are they identical, or they do have different freq response?


mac

[tcobretti]

I think the general opinion is that there is for the most part no aural difference between PNP and NPN if you can get equivalent transistors.