The HE-6 is a dragon to slay in terms of amplification. At least that's the educated word in and around the audio water cooler. I'm listening to Cool Blues on them now, powered by the iFi-Micro iCAN. I suppose it's the little amp that Can Can, because I'm enjoying the presentation between my ears in a way that I'm mildly embarrassed to admit. The volume knob is right around 6.5 to 7 on a scale from 1-10. Using sound shaping and bass switches has more effect than on any can's yet...the differences, as one might expect, are simply more there on Cans so discerning as the HE-6's. The presentation is one of, all the music. The presentation is one of a whole but wherein every element of the tapestry can be seen in all of its color. (part of that is what you are listening for...if you want to sit and consider what type of skin is on the snare, or if the horn player is using a #3 or #5 Rico, you can do that with these, but you don't have to.)
Anyway, I just meant to be breaking them in and copping a listen. Frankly, I didn't expect to write anything until I hooked the HE-6 up to the EF-6. In any event, unless you are one who needs merciless volume, I can't imagine you'd need more juice. Are there other amps more suited to drive the HE-6, without a doubt...several of which we carry at StereoDesk, but that the iCan can do it and leave you not feeling short changed, or anything but grinning says a lot about their design and engineering. There you have it...$250 for an amp that moves air on planars. Who'd a thunk it. Even as I turn the volume knob to 9, things don't get ugly, rather just more volume.
YMMV if you need uber juice, but for a fine listen, don't write off the i-Can regardless of your Cans. Hey, you can always send it back within 30 days for a full refund. So far, none have returned. Also an affordable way to add another location to kick back and listen on any variety of cans. I'd also add that these things are magic on the HE-400's...Still, right now, I'm in dreamsville.
Los Hombres Calientes are playing a live concert in my head, gotta run. (also, you'll never really know the genius of Ray Brown until you hear his tone on a great pair of planars headphones-faultless.)
Notes on the iFi with other Cans, and HifiMan with an array of other amps, forthcoming...really, this is too much fun.