Tonemender Debug (I think)

[MmmPedals]

I built a tonemender from runoffgroove.com http://runoffgroove.com/tonemender.html
For the most part it works fine and all the controls works as expected.......
.....Until the boost and bass or treble reach a certain point. then there is a huge volume drop.
To explain myself better: If the tonestack is set "flat" (bass and treble at min. mids at midway) then the boost works fine all the way up to max. Then if I turn the bass or treble up until a little past half way the volume drops off to very little.  I can get the signal back by backing off either the volume or treble/bass.
I am getting some scratchy sound with the rotation of the bass, treble and boost pots. makes me think there is dc leaking in to the junction of the bass and treble pots.
Any idea if this could cause the problem or what possibly could?
PS I used an NE5532

[PRR]

Layout. Take picture.

Output wiring FAR away from tonestack.

Tonestack wiring very compact.

Wires from tonestack to U1b very direct and possibly shielded.

Treble wiper wire NOT near Level pot wires.

[MmmPedals]

Got is sorted.
The joint between pin 7 and c11 was funky. added some solder and it works fine. Not sure how this caused the problem (or how the signal passed at all ) but it works!