Problems with Tonemender Gain Stage

[cab42]

I have built a ROG Tonemender, where I have left out the tone stack in order experiment with different tonestacks and gain stages. So basically what I have is a buffer and a gain stage.

I tested it with RG's Quick & Dirty Test Oscillator and everything seemed fine. I then plugged in my guitar, but no sound! I have swapped several times and it only works with the oscillator.

I have traced the signal and the buffer works perfectly, but the sound stops at pin 5 of the opamp, when using guitar input.

I have also tried injecting the signal directly at pin 5 but that makes no difference.

Any ideas?

Details:

Schematic: http://runoffgroove.com/tonemender.html
Layout: Torchys vero layout. I don't think it is available online anymore. I checked it several times and it looks fine.
Changes: Connected pin 1/2 of opamp to the junction of 1M resistor and pin 5 for bypassing tonestack. Used a TL072 opamp (that was what I had)
Voltages:
Battery: 8.7V
Board: 8.7V
Vref: 4.0V
Opamp
1: 4.14
2: 4.14
3: 2.02
4: 0.0
5: 2.04
6: 4.15
7: 4.15
8: 8.29

Regards

Carsten

[PRR]

What did you put in place of the tonestack?

> 5: 2.04

Looks like a leak to ground in the tonestack area.

[cab42]

My plan was to have the tonestack on a separate board or soldered to the pots, so for testing, I ran a wire, so there's no tonestack at all. Just buffer into gain stage.

I'll (re)checked everything and I think I found a tiny solder bridge. After running a sharp knife along all traces, my problem seems to be solved. Now pin 5 reads 4.15V.

The lesson learned from this is that I have reached the age where I need to wear my reading glasses, when building electronics.

Thanks for the advice

Carsten