King of tone clipping noise/lockup

[SprinkleSpraycan]

Hi all. I'm building a knight of tone PCB. So far I only put together one side to see how I like it. Overdrive works. Boost works. Distortion starts making a low oscillating type noise when gain hits about 3oclock. I had bat46's in the clipping and changed it to 1n41448 and now it makes the noise around 4oclock. What gives?

I tried removing the charge pump but it does the same thing at 9v. I was looking forward to trying the high gain mod but that doesn't seem like it work at all with this issue. What do I not understand about this op amp or is it the diodes? I checked resistors/caps and I have the right values everywhere. I also replaced the op amp and tried an tl072 as well. Same issue everytime.

Check out the build.doc and pics below.

https://pcbguitarmania.com/wp-content/uploads/2022/05/Duke-of-Tone-Building-Docs.pdf

[MikeA]

I had a similar problem in a different circuit that has two clip-to-ground diodes, one of which was not connected and that was causing a low oscillation at high Gain knob settings.  Verify that both your clip-to-ground distortion diodes have good continuity to the signal path on one end, and to Vb (1/2 of the supply voltage) on the other end. And verify that they're both installed with the correct polarity.  Both of them facing one way will cause this as well.
<edit> also maybe some insulation between the back of the pots and the solder side of the PCB?  A piece of electrical tape or some thin cardboard would do it, to prevent them touching and shorting something.

[SprinkleSpraycan]

Checked all of that and it's all good. Still low freq oscillation. Why do bad things happen to good overdrives?

[GibsonGM]

Does anything change if you move the wiring around while it's oscillating?

Is it being powered by a battery or 9v supply? If supply, is it a known 'good' wal wart that has no problems w/other pedals? 

[antonis]

Verify clipping diodes MODE _A and MODE_B are wired correctly on respective switch..
By activating both clipping configurations simultaneously, you might result into annoying effects..

[duck_arse]

do you have any wire connected to ground for the in and out, or are you relying on the power supply wire?

[SprinkleSpraycan]

The wiring at the moment is only the 9v and jack.in and out. This is to plug it in to my breadboard/test box that I always use. The wall wart is also reliable.

There is no wiring for the switch which is mounted to the PCB. Switch is also tested and good.

What's weird is I can dime the gain and it works if I play super soft. The second I push too much signal is when it oscillates.

[SprinkleSpraycan]

do you have any wire connected to ground for the in and out, or are you relying on the power supply wire?

The grounds are all tied together

[antonis]

What's weird is I can dime the gain and it works if I play super soft. The second I push too much signal is when it oscillates.

A wrong value resistor (e.g. 2k7 instead of 27k for R5 or 100k instead of 10k for R3) could easily result into the above issue..

I'd short IC1_A pins 1 & 2 to isolate the problem between stages..