Still Got The FF Blues...

[Arn C.]

I decided to make an NPN fuzzface and see if it comes out without the problems I have been having with the pnp ff.

Well, same problem. With the NPN ff I only had the first transistor(Q1) and for the second(Q2) I used a metal can silicon. I tried to get the hfe's correct (around 74 for the Q1 and 132 for Q2)

With 9 volts applied to the circuit I had the same problem as before. This time I decided to change the resistor between Q1 and Q2(9 volt line) the 330 ohm resistor on the npn ff. I put in a resistance decade box and fiddled around until I finally got the voltages to read correctly. 4.5 on Q2 collector and 1.24 on Q1 collector.

The extra added resistance was 430K !!!!

Q1 C=1.24 B=.088 E=0
Q2 C=4.50 B=1.22 E=.766

Do these values look okay now ?
Will the circuit now work okay?

Thanks!
Arn C.

[ErikMiller]

The voltages look good to me.

As for whether it will "work okay," only your ears can judge that, especially with a Fuzz Face type. :-)

How does it sound? Pretty loud, I'd guess, if you cranked up the 330 resistor.

It's best to leave that one at 330, and do your adjusting on the resistor directly connected to the collector. The 330 one is like a volume preset.

I'd suggest dropping the 330 back in, and stick your resistor box between it and the collector of Q2. Start around 10K and see what it looks like.

Also, do your checking with the Fuzz and Volume knobs full up.

[brett]

Bit of a guess.  Maybe you should check that you're not using a 10k or 100k "fuzz" pot.  (or a damaged fuzz pot).  The higher the pot value, the higher the collector resistor to get that magic 4.5 V.  Anything over 20k on the collector of Q2 is very suspect.

hope it works out for you