Figured it out.  I measured the voltage at the drain of Q2 and it was above 20v!  Dropped it to around 4.5v and it works great now. Apparently it was tweaked with before I got it.

Hi,
I need some help with my Ceriatone built Kleinulator.  It makes a white noise hiss that comes and goes.  It is not a buzz or a hum.  It sounds more like when a tube is making noise.  My Mini OTS does not make this noise itself and I do have the gain staging set within normal parameters through the loop.

The Send and Return knobs make no difference in the level of the noise, but the Recovery does.  When it is making the noise, I can turn down the Recovery and silence the noise...so it would seem to me to be something between the Return and Recovery knobs.  What should I check or replace?

many thanks!