Hi!
I’ve been using the PS-2A for about half a year now, and until now I’ve been using the amp’s own FX loop. When I got a second amp, I wanted to try using the PS-2A’s FX loop so I could more easily use the same effects with multiple amps.
However, using the PS-2A’s FX loop causes such a high-pitched hum that it’s impossible to play at all…
“4-cable setup”
guitar → Quad Cortex input
QC out → Engl E670FE input
PS-2A FX send/return → QC return/send
PS-2A spkr outs to one or two 8-ohm speaker cabinets, depending on the situation
The QC works flawlessly when I connect it directly to the amp’s own FX loop, and the problem only occurs when I try to use the PS-2A’s FX loop. The PS-2A’s “Ground Lift” doesn’t help with the problem, nor does trying the “Ground Lift” on the Lehle P-Split III.
So the problem is apparently not caused by a “ground loop,” since the “Ground Lift” on any of the devices (Quad Cortex Return Out, PS-2A, or Lehle) doesn’t help at all?
All devices are powered from the same outlet.