Pooh Bear wrote in message ...

On my later amplifier designs we offered a Pin 1 lift to solve
groundloop problems with unbalanced sources. Shouldn't normally be a
problem with balanced unless there's a *big* loop.

Even when lifted there was 100n in parallel with 10k to chassis IIRC.


exactly, this is often cause of this solution
if the ground is poor designed, some problems with
the groundloop could appear...