Pepper Spray - C1 question

[Bret608]

I'm in the process of getting parts together for a second Pepper Spray, this time a 'stock' specs version. The closeout sale was the impetus to finally try it after a two-year honeymoon with my Albini version.

I have a question on C1. It mentions that 390pf is listed on some versions. This happens to be the value I was easily able to find in silver mica at work. What impact does this part have on the sound? I notice it works together with C2 at the input but am clueless beyond that. Let me know if there's any reason why this would/wouldn't sound good.

One other quick, secondary question. On Q1, I grabbed a 2n404 at work thinking it would be a low-gain leaker, which I know is okay for the circuit. Instead, it's under 150 ua leakage, and the corrected gain using R.G. Keen's method is 204 hfe! Will this still be okay? The one I got from SB for my Albini one was 57 hfe.

Thanks,

Bret

[midwayfair]

C1 forms a low-pass filter in combination with the resistance between lugs 2 and 3 of the Harm control. When the Harm is at max, the cap does very little (caps without accompanying resistors don't really do a whole lot). This filtering is part of the reason you get more of an octave effect as the input level increases (and why some people prefer both controls at max). Something it does NOT do: filter "radio frequencies" (you may sometimes see people mention this as a reason for small caps at the input of a circuit -- to actually filter radio frequencies you'd need a much, much larger cap ...).

Use a socket for the transistor. Something that high is very likely to cause horrible oscillate in this circuit. It's easy to get trash transistors, though; I'd just get something more likely to be suitable. It doesn't have to be a 404A, any low-gain PNP will work just fine.