So my pedal was not working and while I was troubleshooting the problem, I noticed that the orientation for C12, C16, and C11 (D2, and D3 as well)are labeled differently on the build documents, than on the image that shows the tracing. Quick question, does the circuit flow with R14 passing through C16 or is it opposite?
Angry Charles - JHS Angry Charlie v3
- Thread starter l_elu
- Start date
Chas Grant
Well-known member
Actually it is neither. On IC 2.1 pin 1 is the output, you have the AC audio signal and the difference of the DC voltages on pins 2 and 3. The DC voltage should be about 4.5 volts, the AC voltage will depend on a few things, input to circuit volts, gain settings and the likes actual value not to important, just that its there. C16 is a coupling capacitor, it allows the AC audio signal from IC2.1 to pass through to the output but prevents the DC voltage from pin 1 to pass to output. With out this cap you would hear a constant hum on the output, it would make the effect non usable. R14 is part of the tone circuit forming a high pass filter with C13 and the bass pot( R12 and R15 also). When pot is fully CCW, its going to cut the freq below about 500 Hz from the circuit. When pot is fully CW the cut freq is dropped to about 170Hz.
BurntFingers
Well-known member
Long leg through the square hole.
Chas Grant
Well-known member
Well there is conflicting info, on the web page it has the + lead of C16 pointing down, and the build DOC its pointing up. So that tells me there are most likely, at least 2 versions of this board. So I would recommend looking at the back side of the board. For the caps in question you will see a square pad and a round pad. Long leg (+) through square hole. For diode, cathode(side with line on it) goes through square hole.
Chas Grant
Well-known member
If the parts are installed on the board you can't see the silk screen, usually the square pads are correct, so checking those will tell you if the parts are installed correctly.
Alright, I guess I was being lazy. I'm going to take it apart and check the square pad. Do we think this is probably the reason I'm not getting full volume/ very low voltage on C16 (basically 0). I also get a voltage reading on all other pots accept for the volume A100k. The light works also.
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Very interesting... with no power to the circuit, when I perform a continuity test on D2(left) the red light diode. D3(right) lights up. Does the same when power is applied via battery. is this normal. After the light lit up now I'm getting continuity to the ground with lug 1 & 2. but I'm still not getting any readings on the volume pot.
BuddytheReow
Breadboard Baker
The capacitors are still holding some charge. It should eventually stop
