Muff sounding gated after q4....

[BraindeadAudio]

OK so I made a 4 knob muff PCB , driving 1st clipping stage with LEDs and second stage on a switch to be either LED/Silicon or germanium.  I am using SE4010 transistors. PCB works fine on other units,  now, I am having a problem with something someone may be able to help on.

I made 4 that sound 100% fine, but someone hooked up an 18v supply to one and q4 is making unit not sustain. Almost clipping off the frequency like a power starve is in effect.

Swapped q4 and q3 and unit gates almost instantly, sort of like a Zvex fuzz factory.

Possibly blown transistor? Possibly blown components? Unit is not in front of me so I cant test just yet, just trying to get a head start so I can possibly redesign board if I did something wrong.

I am having them mail the unit back to me to troubleshoot it but I am wondering what could cause this in a muff circuit so I do not have this problem again.

Any help is appreciated.

[BraindeadAudio]

I should say i think, this isn't a madbean board but my own i made in eagle and had made at oshpark.