Rust Bucket debugging

[Jebus]

Hey, I'm sorry to see this so late, and I imagine you've already checked this. But anyway, in your picture of the solder side of the board, I see what may be a joint with too little solder on the top row of IC6. I haven't built a Rust Bucket myself; this is just what I think my eyes are seeing! 

Thanks, I just reflowed all the connections of IC6 (and lots more)!

No offense intended but there's a number of solder joints that look a bit cold. Especially on the pots. Also double check that the body of your resistors isn't too far in the hole and not making proper contact. A little flux and a little more heat should help a lot. 

No offense taken! I added more solder and reflowed bunch of joints.

Here's up to date pictures of the board (these are pretty large, so I don't want to attach them here):
Component side: https://www.dropbox.com/s/5r232med595xfml/_MG_1435.jpg?dl=0
Solder side: https://www.dropbox.com/s/x5wgvm2cfao5idz/_MG_1437.jpg?dl=0

[Jebus]

Hey!

I changed both IC7 and IC8 and it made a change: now I get this weird distorted signal when attack is set between 8 and 10 o'clock. When attack is set above that no effected signal is getting through. I recorded short video to show how it sounds: https://youtu.be/d9TOt1thvUI (It sounds like its oscillating, but its not. First blend is at half, attack at minimum. Then I rise attack and only clean signal gets through. Then I max out blend and turn the attack down to get signal through).

All that noise and weird sound is introduced at IC11. Input of IC11 is fairly clean.

Soo.. Any ideas? 

[Jebus]

Went through all the components again. All resistors, caps, pots, ICs, diodes and transistors are the correct ones. It's got to be a bad transistor or IC somewhere. Or broken trace or bad solder. Now I wish I had socketed transistors on this build. I think I should have spare one of every IC except MN3007..