Help. New EDP less than perfect...

[Mark Hamburg <mark_hamburg@baymoon.com>]

My new EDP (delivered this past week), seems to add noise to the loop when 
I
leave it running. Overdub is off. It still seems to be feeding back at 
100%.
But there's a rumble that builds up under or replaces the signal.

A quick search of my archives brought up various issues that would cause
continual decay, but I didn't see anything specifically about this sort of
problem.

Mark