how do I calculate the cutoff frequency of a base-collector bypass cap?

[midwayfair]

I've had trouble even searching for this information, because I don't know the technical term for these things. It's the little bypass caps between the base and collector (or gate/drain). Same sort of thing that's in op amp feedback loops to "cut" treble.

[PimpMyTone]

I think it s called the Miller effect .

[irmcdermott]

Is there a resistor there to, like a "feedback" resistor?

I've been trying to learn all this math, so I don't know if this is what you are looking for, but I think the formula is 1/2πRC, R being the "feedback" resistor, C being the cap.

the analysis on www.electrosmash.com has been helping me work through it. there maybe be examples on there. sorry, that's probably not much help, because i don't know if it's correct

[midwayfair]

Is there a resistor there to, like a "feedback" resistor?

There is, but it goes to Vb in this particular pedal, rather than the collector. Not sure if the calculation is the same. I'll check on Electrosmash, thanks.

[irmcdermott]

There is, but it goes to Vb in this particular pedal, rather than the collector. Not sure if the calculation is the same. I'll check on Electrosmash, thanks.

Yeah, I'm a total noob with the math stuff, almost didn't post anything, but thought maybe the site would show something similar. Hope you figure it out, if you don't mind, can you share what you find out?