Thanks for all the suggestion guys. I ended up getting a very good deal on an ATI 2007 amp. 100lb beast with 200 watts and seven channels. No fans to deal with, claimed s/n ratio of 120db (their cheaper amps have a 105db s/n ratio so maybe we can trust the specs?). Balanced and single ended inputs. Each of the seven channels has fully balanced circuitry. So basically this amp has fourteen 100 watt amps inside.
It also comes with a 7 year warranty and is made in the USA. Too many reasons not to get it, though I wonder if there is any real benefit to fully balanced circuitry when it's feed from a single ended pre-pro?
Being fan-less I can stick this guy behind the screen to feed all 7 of 11 channels up front.
Originally Posted by coctostan
I've even seen some pro amps that use a noise gate at idle which can give a very nice idle S/N but not necessarily what you want.
Initially I was using a dbx drive rack pa+ to boost the -10dbu signal to +4. Every time there was a gap between songs, you could hear the muting circuit kicking in. VERY annoying, the original drive rack didn't do that.
Originally Posted by MKtheater
I have bought many used amps and some have a hiss and others don't, usually it has nothing to do with the S/N ratio but leaky capacitors or bad resistors and once repaired they all become silent.
Those noisy XLS's were all bought new. I had five of them at one stage and they all had the same issue with hi-efficiency speakers. They were fine on normal speakers. Possible they all had the same fault from the factory I guess.