Hi Stevan, You need to be careful with under 4ohm types, but anything else is good. If you have a fairly clean power supply then you are good. Try the 1000watt monos.
Hi Stevan, I have found valve amps have too many short comings. I have found other ways to get the fluidity valve fans adore.
I have to say you have work real hard to beat the ICE power type amps. They are utterly a revolution for audiophiles. They are cheap, powerful, run cool, with very low distortion and the size of a shoe! No heat sinks to cut your hands on or even break your back lifting them. Just make sure your source is good and up to date and you will be happy.
Another Apogee man here! Try different amps from Krell. In the old days they were probably the only thing that could drive Apogees. Now the Technology has moved on... Belcanto e1 will kill the KSA Krells in every way. Tubes are a little more tricky in my opinion with these. The Apogee is capable of mind numbing bass and tubes will detract from their bass performance although the mids...