[quote name='Lew-Bass' post='648906' date='Nov 8 2009, 04:49 PM']I think it's something to do with this. This only happened since I put something into the effects input and outputs (headphones, I DID ask where to put them! ) and it started, i took them out of the effects input/output (cant remember which) and it stopped, but then another time 30 minutes or so later it re-appeared, I turned it on and off and it was fine... [/quote]
Lots of people had problems with the Genz Benz Shuttles when they first came out, problem caused by the "make/break" jacks in the send and return. I wonder if these amps have been lying aroung for a while and the "closed" contacts of the send/return are causing the hiss. Just another theory!! Try cleaning the jacks with Sevisol 10 .
Iain H