Sans Amp GT 2 Debug

[rasco22862]

Hi, i finished this building from tonepad- I used TLC2262CP for IC2,3,4 and TL072 for IC1. My problem is that with certain configurations of the rotary switches, i hear an ugly oscilation. Also i used shielded cable, connecting the shield to the sleeves on the DPDT IN/OUT connections, and  connecting the shield to the 3pdt ground lug on the DPDT In FX/Out FX connections. Also the volume pot at 7 o´clock (minimum) reads 13k between lug 2 and 3. Is this correct?. Here are my voltages:

IC 1:

4.54
4.54
4.13
0
4.13
4.54
4.54
9.08

IC2:

4.54
4.60
4.52
0
4.54
4.60
4.54
9.08

IC3:

4.54
4.54
4.51
0
4.50
4.54
4.54
9.08

IC4:

4.54
4.54
4.54
0
4.54
4.54
4.54
9.08

2n5088:
_____
9.08
4.53
3.92

Thanks

[rasco22862]

 

[rasco22862]

What about the voltages?

[rasco22862]

I mean in some combinations of MIC and MOD i hear a noise in background. It gets more quiet when i turn the drive pot to max.

Is this normal?

Please

[Johan]

thats a quite advanced project and I dont think too many has built it, wich is why noone has responded...but if I remember correctly there is many cables going to the switches..try moving them around..it might be oscillation somewhere...
j

[rasco22862]

The drive pot is who regulates the oscilation. In a few combinations of mod and amp(dirty), the drive pot controls the oscilation. Sometimes more drive is less oscilations and sometimes more drive is more oscilation. I double checked everything, I move the cables but nothing the oscilation goes on. I used shielded cable. Should i use shielded cable for the pots? Should i start to check PCB´s componentes? I mean, i have signal in every combination.

Thanks

[rasco22862]

What can i do to stop the oscilation? Should i use shielded cable for the drive pot?

[rasco22862]

 

[rasco22862]

Ok, i fix a bad solder. The old oscilattion gone, but a new one appears with the drive pot, but this time is a high pinch oscilation that is very anoying. The drive pot is who regulates the oscilation.

[rasco22862]

Thanks to all I finished, the oscilation stops when the guitar is plugged in the input.