Fuzz face npn and pnp questions

[Mustachio]

So I built a a GGG fuzz face last year with silicon transistors, I used the 2n2222 metal cans. This last week I decided to change it up to germanium trans and bought a matched pair off ebay  ...... I know I know I shoulda went with small bear and I will on my next purchase. So what I ended up getting off ebay was a matched pair of ac128K and an ac176K. I didn't check the datasheet ahead of time and I really cant find great info yet on them but it seems after testing on the dmm the 128 is PNP and the 176is NPN. They test pretty close hfe.

So from what I understand I cant use these together in this circuit. Also I was going to use this

http://www.sabrotone.com/wp-content/uploads/2011/01/Charge-pump.gif

to supply the -9 and use the +9 for the led

I wasn't sure but should I flip the polarity of the electrolytic caps ?

And what does everyone suggest ? Use one Si tran with a Ge as long as their both PNP or NPN (with corosponding Ge)? Or order another set from the same guy ? Or order new set or singles from small bear ? which I will probably build a few more fuzz's and order from small bear or from the store here if there are any specifics you guys can suggest.

[slideman82]

IMHO, use a PNP pair (first PNP 70-100 hFe, 2nd PNP 90-130 hFe) and use a non alkaline 9V battery. They last a lot! If you use a led, use a high brightness one (3mm, could it be blue or red), limited with a 15k resistor, so it drains low current.

[R.G.]

... what I ended up getting off ebay was a matched pair of ac128K and an ac176K. I didn't check the datasheet ahead of time and I really cant find great info yet on them but it seems after testing on the dmm the 128 is PNP and the 176is NPN.

So from what I understand I cant use these together in this circuit.

That is correct. They must either be both NPN or both PNP. Since you have one NPN, you can't use it, unless you use it with one of your silicon NPNs or find another germanium NPN somewhere.

to supply the -9 and use the +9 for the led

An LED doesn't need +9V. It only needs a voltage difference across it. It will work fine from -9V. However, using +9V and a charge pump to make -9V just for this circuit will let you use a PNP fuzz face from a negative ground (that is, +9V and ground) power supply and share the ground lead. This is an advantage for ease of powering the resulting pedal.

I wasn't sure but should I flip the polarity of the electrolytic caps ?

If you mean "in converting the NPN silicon fuzz face to a PNP, positive ground effect, should I flip the polarity of the electrolytic caps?" then the answer is yes. Electros must always have the applied voltage be in the correct direction.

And what does everyone suggest ? Use one Si tran with a Ge as long as their both PNP or NPN (with corosponding Ge)?

I suggest that for quick and easy, especially if you socketed your 2N2222 transistors, you try the NPN germanium in each transistor socket and see how you like it each way. Only if you don't like the result either 2x silicon NPN, or 1 silicon, 1 NPN germanium would you rebuild it. In fact, why don't you just build a *second* fuzz face with the PNP germaniums and compare that? Leave your NPN with either 2xS or 1S1G. They'll sound different. Whether one is better than the other is a matter of taste.

Or order another set from the same guy? Or order new set or singles from small bear ?

I would build a second one for the 2x PNPs and compare with the various combinations of 2xS NPN, 1S1G NPN, 1G1S NPN. You're most of the way there already without ordering new transistors. Get some information, then decide what you like and which way you want to go. It is *possible* that you'll like the 2N2222 version best if you can submerge the propaganda that germanium = good from your head. Some people do. And be aware that distortions sound different to your ear when they're at bedroom volume versus stage volume. 

[Mustachio]

Thanks guys ! I ended up ordering a few more pnp Ge's from some one else. Ended up finding some for cheap just to test around with.

Slideman thanks for the hFe ranges! The new ones I ordered tested good for Q1 with very low leakage! and ill try the larger resistor to the led thanks man!

I wanted to do the charge pump just in case me or anyone plugs it in with the wrong psu. I tend to stay away from batteries in my builds. So I will flip the +\- on the electro's and do the charge pump, I already have parts on the way for it and a few more builds.

After I posted last night I thought I should try this ac176k with one of the 2n2222's since their socketed , its like you read my mind 

As well as building a few more fuzz faces on vero and testing out all the trans. So the plan is in motion!

Also R.G. I wanna say thanks to you I've read so many of your posts that have helped me fix every project Ive had problems with ! You sir deserve an award ! Especially the info you and PRR Have given in regaurds to the dynacomp and debugging in general! you guys are great!