Vintage kit fuzz - 1.5 to 9v conversion advice?

[RickL]

I love simple little projects like this one. I built two of them one with NPN transistors and one with PNPs. The PNP version is simple, all you have to do is reverse the power supply, no polarized caps.

I fiddled with a bunch of different transistors and it seemed to work best with very low Hfe, around 50. I used a 100k pot for volume and this puppy is loud. Unity volume is less than half way up on the volume pot. Pretty clean with the volume pot on my Tele copy up to about 7, then the grind starts. The only other change I made was to add a spdt centre-off switch to add either a 4n7 or 4n7 and 1nF caps in series with the stock 100n cap. It gets kind of ice pick-y with the 1nF and quite a bit quieter, but there's lots of room on the volume pot to make up for the loss.

I tried both Si and Ge transistors for the PNP version and ended up with a couple of random Ge ones from my junk box, both about 50 Hfe. Si transistors with Hfe equal to about 150 worked okay too. Maybe a good use for Ge transistors with gains too low for other projects.

The trim pot didn't seem to have much effect on either of my builds. Maybe a little extra volume from one end of the pot to the other, but no dramatic changes in gain or tone.

My guess is that an AA battery will last forever so unless you absolutely have to hook it into the power supply on your board, I'd just use a battery. I don't play live any more, these will just be two more to put on my shelf.