Help with Fuzz Voltages (Radio Shack Fuzz)

[PeteG45]

I found the schematic and layout to build this "Radio Shack Fuzz" on another website. I've built the circuit and checked it over about a dozen times and it still sounds really bad. The tone sounds mushy (bassy) and the fuzz is really blatty and harsh. I've been reading a lot about fuzzes and it seems like the voltages at the transistors that I get are really different from other pedals. Are there standards for voltages when using 2N2222 transistors? According to Small Bear Electronics the collector voltage on Q2 should be about 4.5v and I'm only getting 0.93v. I know that this is dependent upon the resistors in the design but that's a big difference. Is this collector voltage even close to correct?

[Jazz P Bass]

The collector of Q2 should sit slightly below 1/2 of the battery voltage.
(It is a class a circuit)
In this way the output can swing that much both ways and if it should clip, it will clip symetrically.
Go back & check your work.
A transistor installed incorrectly, a resistor in the wrong spot.
Check both collector resistors for the correct value.

[Enzo]

You say "when using 2N2222." To me that souinds like the original design was for a different type transistor. Is that so?

ANy chance the original design was for something like "C945" transistors? WHich would be 2SC945 in real life. Or 2SC- anything

If so, I bet your problem is that they are in wrong. Looking at the flat face of a plastic 2N2222, the three legs are left to right: emitter, base, collector. The front face of a 2SC945 would be: emitter, collector base. The two may be interchangeable in the circuit, but the legs are in different order, so to go from one to the other means one would have to be turned sideways and the legs bent funny. Nothing wrong with doing that, but you MUST get the legs in the right holes.

If the 2N2222 is the small round metal version, looking at the bottom, ther is a small tab sticking out the side. That identifies the emitter, then clockwise from there will be base then collector. Still not the same leg order as a 2SCxxxx type.

COuld that be your problem here?

[PeteG45]

According to the thread this was designed for the radio shack 2n2222 in the black plastic housing. They come in a multipack with two other transistors. I'll triple check the spec sheet and check my orientation.

[Jazz P Bass]

Here are the datasheets.
Metal can (2N2222) & plastic package (MPS2222).

[PeteG45]

I looked up a spec sheet for the 2n2222 and as soon as I saw the assignments I knew mine was wrong. I am so sure that I checked and double checked the spec sheet and the orientation. As soon as I flipped the transistors I got fuzz without all of the noise. Thanks so much.

The voltage at the collector is about one quarter of battery voltage but it sounds pretty good. I might install a trim pot and play around with that as well as adjusting the cap values (now that it works). Once again you guys rock! Thanks to everyone.

[J M Fahey]

Yes, I calculated Collector2 voltage as about 7V below whatever your battery puts out .
You might lower that 10K resistor to something between 4K7 and 6K8 or raise the emitter2 1K resistor to 1k5 to 1k8.
Anyway, symmetry in this case is not needed , I might say it should be *avoided*; itīs a Fuzz circuit, after all.
Congratulations.
Enzo, as usual, straight to the point.

[PeteG45]

I'm going to try a 10k trim pot in place of the 10k resistor. I've already ordered it along with some other stuff that I needed.