Parentheses - High pitched whine without a buffer in front

[Coop]

Absolutely love this pedal. I have been using the Rat side as a boost into my Wizard MTL clone and it is one of the only boosts I like with the amp. Adds just the right amount of grit and aggression with the volume cranked and the gain just barely on. I wasn't able to find a LM308 so I am using a OP07. The pedal makes a high pitched whining noise. It seems to get worse if I kill the signal with a killswitch on my guitar but it is always present. I tried playing with my grounding and another power supply with no success. For fun I tried running my SD-1 clone into it and the problem was resolved. Any thoughts on why it would need a buffer out front?

 

[hamerfan]

I am not sure whether this solves the problem, but the TL071 does not need the comp cap C15 as the LM308

 

[Coop]

I am not sure whether this solves the problem, but the TL071 does not need the comp cap C15 as the LM308

This is an OP07. Same deal?

 

[jwin615]

I've heard of others having this issue with Rats usually fixed with a buffer. There's an obscene amount of gain produced and oscillation can be a problem.
May be worth double checking the solder joints around the negative feedback loop and make sure you don't have any small bridges
C15 isn't needed for op07 but I don't think it's causing issue.
May also be worth audio probing and trying to see where the oscillation is coming into play.

What's up with R20/C9? 60hz low pass? Shouldn't those be inverted to be a high pass? What am I missing?

You could try running a small cap, like 10-100pf between pin 6 and 4 to bleed some highs at the output to ground