Colorsound Overdriver/Black Arts Toneworks Black Forest Voltages

[Zounds!]

Oh no! This looks bad. Basically there was no reason to desolder everything, because Q3 is isolated in DC  from Q1 and Q2 using capacitors. The situation was still good when Q1 and Q2 were at the correct voltage levels.

Ah haha too late now! I started desoldering and testing with the components around Q3. That solved my biasing problem on Q3, but then Q1 and Q2 were off, so I continued on through the rest of the board. So I basically did build it again! But...

- Put in Q1 and Q2 with R1, R2, R3, R5 and R6 including battery connection. Measure that bias is ok.
- Put in Q3 with R11, R12, R13, R14 and C10, C11. Measure that bias is ok for all three transistors.
- Start placing the components for the tone section one-by-one. After each added component, measure bias for all three transistors. This way you'll notice if any added component breaks the biasing. This approach should isolate the problematic part, if any.

This is a really good idea. In measuring all of my components I've realized that it's a really good idea, especially for someone like me with such poor troubleshooting skills. Tested components + bias readings after every new component = a working circuit, finally...I hope!

[Zounds!]

I just stripped every last component and wire off my board and started with your instructions from step 1:

- Put in Q1 and Q2 with R1, R2, R3, R5 and R6 including battery connection. Measure that bias is ok.

My voltages now:

Q1
C 2.66
B 1.89
E 0.0

Q2
2.16
2.65
1.92

Could different transistors account for having different voltages than the ones you posted as a guide? Q1 looks ok I think, but the voltages don't match yours despite using the correct components. Q2 doesn't look right -- either the collector is too low or the base is too high? Will the voltages shift to normal once I start adding other components or is this it? I'll wait to go forward as I don't want to complicate things. Right now the only things on the board are R1, R2, R3, R5, R6, Q1, Q2, ground, and 9v. Thanks again for your patience in walking me through this incredibly frustrating build!!

[jatalahd]

Ok, just to make sure, you should have 100k resistor from battery to collector of Q1, 6.8k resistor from ground to emitter of Q1, 1.8k from battery to collector of Q2, 470 ohms from ground to emitter of Q2 and the feedback resistor 150k from emitter of Q2 to base of Q1. If you are only looking at the vero-layout, you need also the two black jumper wires in place, which add the ground connection and connects Q2 emitter with the 150k resistor. I usually prefer to just look at the schematic and build according to that and that is why i did not mention the jumpers (my mistake).

Using different transistors will have only +- 0.3V effect on all voltages, so my reference values should hold within these limits (except for Q2 collector voltage which can vary +- 1.0V). Q1 emitter should definitely sit about 0.3V above ground and not measure 0.0. With your new values, there is something wrong at Q1, possibly Q2 will correct itself when Q1 is fixed.

- Check if adding the two black jumpers fixes any problems
- Check that you are still getting +9 volts from the battery, when connected into the circuit. If not, then it would suggest a short somewhere.
- Check that the pin-out of Q1 is correct

Other components should not affect the voltages of Q1 and Q2, so once you get this right, then the DC voltages should stay fixed throughout the rest of the build.

[Zounds!]

I'm sure you're not losing any sleep over this, but I just wanted to drop in one more time to let you know that I'm going to put this project aside for a bit. I've ordered a Colorsound Overdrive PCB which I'm just going to populate with the Black Arts value components and just toss the current vero. All of my vero builds end up a mess, so I think I ought to spend more time practicing my soldering and wiring on PCBs even if it costs more and limits me to circuits someone's made boards for (not really looking to fabricate my own at this point). I still have no idea what went wrong with this, but hopefully I'll be able to finish this up using a medium that's not as finicky as vero for a hack like me. Thanks again for helping out though!

[jatalahd]

I really hope that you'll get it working eventually. I have had some hard times too with vero-boards, typically the problems have been soldering related. When you get your PCB populated, please drop a status report in any case. You have worked hard on that build so I want this thread to have a happy ending

[duck_arse]

zounds, Zounds!, get those other boards out, have another look over them, then start new threads (not all ot once, obviously), give the rest of us something to lose sleep over. the only way to improve yr skills is to have something to work on.

[Zounds!]

zounds, Zounds!, get those other boards out, have another look over them, then start new threads (not all ot once, obviously), give the rest of us something to lose sleep over. the only way to improve yr skills is to have something to work on.

Haha thanks for the encouragement! I'll be back with new frustrations soon enough! 

I got this circuit working in no time with the PCB I bought, but only after I realized one of my transistors was shot. D'oh! I used an input cap blend pot instead of the rotary switch and am finally getting to enjoy the thing! Thanks for all the help folks.

[jatalahd]

finally getting to enjoy the thing!

This is good news!