If you're looking at dedicated headphone amps, then any "good" otl tube amp will work fine(ex. little dot mkiv). I had great results with the ming da mc84c07. It's transformer coupled, but doesn't use step down resistors. So it will drive just about anything. The best amp I've heard them with was a balanced bijou. That's a diy amp and may be hard to come by. But if you're thinking vintage, then anything from the pioneer sx line or some of the 70's yamahas will work good with them. The marantz's, like what you have, are just a little too warm sounding with them imo.
Edited by moodyrn - 11/14/11 at 10:23am