Hmmm...not sure it is powerful enough to REALLY drive 600ohm cans -- you might want to just send Spencer an email about that. But as far as I can tell, those cans should only have an impedance of 62 ohms, so you're good. I can confidently say that the Enabler certainly has Hi-Fi quality sound with no noise unless you use cans with really high sensitivty -- you are also okay here since the Q701 are only 105db. I use 1964ears Quad in-ears (don't really need an amp) which have high sensitivity so I do hear slight hiss (118dB SPL/mW) as well as a pair of modded Altec Lansing im716 (essentially an Etymotic ER4-S, much better when amped). The Enabler just sounds fantastic with either one and I'm very glad I got one.
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