I just bought a Nuforce P-8 preamp to match my Nuforce 8.5 amps. My previous preamp had developed a hum. I don't know if you would call this a level, but this has got me thinking. The P-8 and 8.5's together give a sound that makes me question mixing and matching preamps and amps. I can play whole cd's now. When we mix and match, don't we also just listen to a cut from one, and a cut from another cd(or lp)? Shouldn't we ask, "can you play the whole cd and does it all sound good?".