suggestions for a headphone amplifier

Daltonlanny -

IMO the Senn 650 has a smoother, richer midbass and better balance than the 600. I find the midrange of the 650 is flowing and the highs are smooth, with a slightly dark presentation. To me, the sound of the 600 is generally similar to the 650; however there are some slight differences - the 600 treble is grainier, the midbass is boomier, and the bass is less robust. I also find the 650 to be more comfortable than the 600 and I have less listening fatigue with the 650.

Also, the MF X-Can does not lack power to drive the 650.

John

Thanks Johnrob!
Lanny

Another vote for the Antique Sound Labs Head MK III. This is a fine, economical intro to the magic of the SET experience. I thought the MF X-Can perfectly capable, but the ASL added that special quality of living air; with a marvelous hang-time for a note's resonant fade-out ...

Group,
It's one day later and I am savoring all of the suggestions.Some additional snooping on my own has uncovered Audio Valve RKV MK11, Singlepower offerings, enen a Gillmore new offering or the established Little w/ dedicated power supply. In some instances my 500.00 dollar ceiling is blasted, though I knew that would occur anyway. Headroom amps are for the most part unavailable for now, and I guess that their new line won't show for a month or two. Looks like there's a ton of great product out there. Tough choices!!!!!!

Don't forget to replace the stock 650 cord with the Zu Mobius one. I use a Headroom Max amp (with the new reference module that is in the latest version). This all works fine with me. Kubala Sosna Emotion ICs work well well with the 650s, as the ICs complement the 650's slightly dark sound.