Colorsound overdriver (Madbean Cherrybomb) ineffective EQ

Started by VPIF, November 21, 2013, 09:32:41 AM

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VPIF

Hi.

Built a Madbean Cherrybomb on a prefabbed PCB ( http://www.madbeanpedals.com/projects/Cherrybomb/docs/CherryBomb.pdf ) Finally got it to to work after some frustrating debugging sessions, sorting out a short circuit. But now it turns out that the bass and treble controls have minimal - if any- effect on the sound or volume, and the overall volume is lower than I'd expect  (unity at around Vol: 50% with Gain at 25%). I also occasionally get French radio, but this is probably due to the fact that I haven't grounded the enclosure yet. Voltages are off (see below). Transistors are BC109 BTW..

Battery: 8.84V

Q1:
E: 0.38V
B: 0.93V
C: 1.92V

Q2:
E: 1.29V
B: 1.93V
C: 3.84V

Q3:
E: 0.0V
B: 1.53V
C: 8.80V

There is 470 Ohms of resistance to ground from the emitter of Q3, as it should be, so it's not exactly shorted to ground. There is continuity from the transistors to what they are supposed to be connected to. The voltages should, if I understand correctly, be around 4.5-5V and there seems to be something fishy going on around Q3.

Any helpful Points in the right direction will be appreciated. Thanks.


duck_arse

q3 c at 8V8 means it's not drawing current, possibly not connected to its resistor, surely.
" I will say no more "

VPIF

Tested the transistors a while ago, but mucked about with them quite a lot since then and I must have killed one of them in the process... Popped in some 2N5088s and it works now. I was simply not knowledgeable enough to understand that the transistor could completely pacify the tone stack. Going to try som different transistors now, to see if I can make it sound a bit sweeter.

Thank you for your input. It did probably save me some time and anguish  :)