After I got my first fuzz face clone to work, I liked it so much, I decided to make one for my friend. I wired exactly the same as my first one (see attached circuit and stripboard image) except that I replaced the original Si Q2 (BC108) with a 2N222A. For some reason the gain at both the Si and Ge Q2 collectors are 9.32. It's like the current is somehow bypassing the trim pot resistors I installed.
I rebuilt the circuit, same problem. I rebuilt the circuit a third time, but used PC circuit board instead of strip board to make sure there weren't any connections where they shouldn't be. I also direct wired the Q1 to the ground and wired the collector of Q1 directly to the base of Q2 (see picture). Same problem.
What am I missing here?!?
(https://i.postimg.cc/qNgvXLtw/fuller-schematic-and-transistor.jpg) (https://postimg.cc/qNgvXLtw)
(https://i.postimg.cc/Sn5NZMCh/modfuzzface-OG.jpg) (https://postimg.cc/Sn5NZMCh)
(https://i.postimg.cc/kRnnVF3x/B16-B294-A-5401-43-F3-BA80-327810-B12-DE2.jpg) (https://postimg.cc/kRnnVF3x)
Quote from: guywonder44 on May 03, 2022, 09:20:27 PM
For some reason the gain at both the Si and Ge Q2 collectors are 9.32.
If by "gain" you mean "voltage", it might be due to the use of n-p-n Si BJT instead of p-n-p one.. :icon_wink:
Your board calls for negative ground & n-p-ns where your schematic calls the the opposite..
This might be a good starting point for what you want to do, guy! https://fuzzcentral.ssguitar.com/axisface.php (https://fuzzcentral.ssguitar.com/axisface.php)
It'll work with your transistors, but you may wish to use some sockets to try swapping them out later, after it works...
If the germanium transistors you used in the first working circuit were NPN, and those in the current one are PNP, then it would explain why the first one worked and this one does not. (It's not visibly evident what the Ge transistors are in the photo.)