Q8, Q9, Q10 IN TB303

[zbr]

Hi All

I've just replaced Q8, Q9, Q10 (and Q11 too which I had to undo coz I lost control over my filter frequency in my x0x

I've recorded a run through a pattern before and after

http://soundcloud.com/hacl/x0xb0x-stock ... comparison

It is better if you ask me, and it was fun to do it, but the difference is subtle enough that you can only hear anything in the WAV and mp3 (which I normally love) is just cutting all the difference out - which means that there isn't a whole lot of difference

[guest]

what did you replace them with

[zbr]

oh, of course, I should have said
It's same 2SA733P just some that were supposed to be selected for higher beta (in the 360 range).
I guess the stock ones were not too bad either. or those were not as good. or just the difference isn't that great overall.
I don't have the facility to measure beta in the ones I had there before I'm afraid so the test doesn't actually say much

[antto]

i just figured: how can these make "acid resonance" when none of them are involved in the resonance, at all?
Q8 is important for the square shaper
Q9 adds the bias to the cutoff/envmod coupling (according to the manual)
Q10 is part of the cutoff/envmod coupling
none of these have anything to do with the resonance
tho, maybe 9 and 10 have something to do with the "gimmick" circuit, as the Accent pulse goes thru these