What are your favourite tube screamer mods?

[Brett]

You should be fine with the switching you have if you’re using off board bypass switches for each circuit. It may be a good idea to adjust your net labels so your CAD software shows the correct connections when you start your layout.

 

[neiltheseal]

Hello again.
I finally got around to putting this together and (as I had suspected) it doesn't work properly.

Would anyone be able to have a look at the schematic for me and give me some tips re why why it's not working? The most recent schematic is attached.

It passes signal so that's a win, however there is no gain. With an audio probe I have tracked the problem to IC1.1. The signal enters strong on pin 3 but comes out extremely weak from pin 1 and therafter.

I measured the voltages and they are as follows:

1. 7.8
2. 7.8
3. 0.2
4. 0
5. 7.6
6. 7.6
7. 7.6
8. 8.6

This seems to confirm the problem is here as I assume that pins 1,2,3,5,6 and 7 should be about 4.5v. I suspect this means that I need to bias the op amp but I have no idea how to do this.

Thanks!