Transistors on a Rotary Switch

[lucidgenius]

I currently am running some of the following:

BC108
BC109
2N3904
2N5088
BC184
2N7000 (-removed this was causing errors only on second stage Q2)

[eatyourguitar]

why not calculate the difference in collector resistors and attach them to the collectors while your switching them on a 2P6T?

[lucidgenius]

I've read that keeping a germanium pedal powered on for a few days stabilizes the tone, but maybe that's just internet B.S.

[eatyourguitar]

I think the temperature swing with germanium is real but it is more a result of ambient temp rather than heat generated from passing 10microamps of leakage. I have never ever touched a germanium transistor in a guitar pedal that felt warmer than room temp. I believe running power through a component to keep it warm and stable is a real thing on a synth where very small changes have a dramatic affect on tuning stability. your gains on a germanium tranny might change %5 with a 2 degree F temp change but trying to actually make the transistor rise 2 degrees with no base current modulating collector current on a low leakage germanium is yet to be seen. if you have done some tests on the subject I would be very interested to see how it went.

[lucidgenius]

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[eatyourguitar]

I haven't done any tests... but rather assuming (please forgive any blanket statements made), I've read that keeping a germanium pedal powered on for a few days stabilizes the tone, but maybe that's just internet B.S.

there is probably some truth to this but I would fancy a guess that it is more like an electrical burn-in time (not actually burning) rather than a temperature swing that changes gain and the collector bias. no word on if this makes them better or worse but it could make them more consistent if you were doing multiple takes for an album in the studio day after day. might also drain your battery some too. notice that there is some base + collector quiescent current flowing when a fuzz is powered on but not passing audio. this means that the transistor is passing more than the leakage and therefor could actually warm up more in the real world with the example you describe.

I added a jumper to tune leg 3 and it fixed my voltage error on Q2. What voltage should I see on the Q1 collector?

I'm sorry but there have been so many changes to this project I would have a hard time visualizing it in it's entirety without a full %100 accurate schematic and all your voltages and gains. I'm not asking you to do that however. it would probably take you longer to document your work than it would to try some things and do some tests on your own. I'm going to leave it since I have nothing helpful to say about your specific situation. I was going to suggest reading a book on the BJT transistor as a semiconductor device. I just finished hitting all the books a few months ago and it helped me tremendously to be more self sufficient when it comes to design and troubleshooting of transistor circuits. I hope I don't sound like a condescending old man telling you to open a book. just giving you some solid advice is all.

[lucidgenius]

Yeah, I don't blame you, This post is 2 pages worth of troubleshooting a schematic error. I've made the appropriate adjustments to the schematic and all seems to be working now.

I appreciate your help and resources.

[eatyourguitar]

Q1 collector is the same voltage for Q2 base. for me 1.8v to 2.3v is typical but I think you could have anything from 0.8v to 3v and maybe even lower for germanium. you need to consider at what current and voltage to Q2 base it will go into full saturation. once it is saturated, it does not turn on more than it already has. it is totally possible to have Q1 C Q2 B biased at or above the point of saturation and still get a good fuzz sound. AC swings both ways at Q1 base so it makes sense that a positive swing will turn Q1 ON and bring the collector right down into the linear operating range of Q2 for part of the waveform. this will create some kind of rectifier with the square waves that we call fuzz. for germanium I like them biased closer to the standard values from the very old units so I leave R1 as-is most of the time and just play with swapping R2. for silicon FF I usually break all the rules and do a shit ton of mods till I have something I actually want to own. colorsound one knob fuzz is an example of a basic mod. muff fuzz is another. this list of mods on the internet goes on and on.