Bass mod for my BYOC MKII Tonebender? Transistor Question

[VeridisQuo]

I don't know if the transistors in the BYOC MKII kit are NPN or PNP but I'm wondering if I can swap them out with NPN or PNP transistors like a bc108 or something like that?

I'm trying to find a way to make this fuzz have more low end and just have "more". Do you guys know if switching out the transistors will do that? Or is there some capacitor or resistor I can change to make that happen?

[VeridisQuo]

Anyone? No?

[PRR]

> Anyone? No?

some of us can't remember EVERY brand and model of pedal out there...


A link to your particular pet would be nice. (And more useful than the image.)

> more low end ... switching out the transistors will do that?

No.

Modern transistors do not care from zero frequency to over 10 MegaHertz (1,000 times higher than the top of the audio band). You won't get "more low end".

Ah..... OC75 is PNP and Germanium. Very old. It will still cover the whole audio range, and certainly midrange as well as bass.

However Germanium allows cheap tricks which do NOT work on modern Silicon devices like BC108 (which is NPN). In particular, Q1 is biased-up by self-leakage. Germanium leaks enough for that to work. Silicon does not.

"more low end" is usually capacitors.

Raise C2 0.1uFd to about 5uFd. This will be electrolytic, put the "-" leg away from Q2. Work carefully. Test this! Put that 0.1uFd in place of C3 0.01uFd. Test this.

It is very likely that you can have "TOO MUCH low end". Low notes and high notes distorted together make awful sounds. Most distortion circuits trim as much bass as a soloist will tolerate. So be prepared to go back split the difference between the factory's shaved-bass cap values and my over-size cap values. Maybe 0.5uFd at C2. (C3 is probably not so critical.)

Read DC Volts from chassis ground to Q1 pins. Voltages will all be "-". Collector must be above -1V but below 8V (on 9.0V battery). If it is slammed to zero or full battery voltage, it won't be happy. If slammed, swap with Q2 or Q3, see if the new Q1 biases itself better. 2V to 6V would be a zone. Then re-do the VR3 trimpot bias-set on the new Q2 Q3 pair.