headphone amp under $350

I need recommendations for a headphone amp. I'd like to max the price at $350. I will likely use it with a Sennheiser HD-580. I listen to classical and jazz. I'm going to be using the headphones at night so I don't disturb (and am not disturbed by) my neighbors.

I'll be plugging my arcam alpha 9 cdp directly into the headphone amp. I want detail without the sound becoming analytical and prefer balanced sound top to bottom rather than something that really features the midrange (or lows/highs).

Either version of the Antique Sound Labs MG-Head, all tube, TONS of gain, or the V2 version of the Musical Fidelity "X-Cans" (has (1) tube, but more of a hybrid-type design, with slightly more speed and detail).

Have used both extensively with HD600's, really depends on your "taste".

Plenty of great choices in this arena! Kinda nice to look into an affordable category, with so many options, for a change, eh?

Good luck!
Go with a "Headroom" amp,they "all" sound great.Will blow away,the one's that are mentioned here.Ron...
I've heard very good things about the ASL. I'll look into the others that were mentioned as well. Thanks.
I auditioned the ASL (v.1) vs. the X-Cans (v.2) with my HD600's, and bought the MF unit for its superior sound (the ASL, much as I liked it, just sounded too 'tubey' [or 'transformer-y' - I believe it was transformer-coupled] in an obviously colored sort of way, even with upgraded tubes, while the MF [also tubed, but direct-coupled] sounded more neutral, dynamic, and faster, though I don't know about the latest versions of each unit). However, the unique, plastic-encased output jack assembly on this v.2 of the MF is just a terrible part - I've been through two of them already and need another one, because the extremely thin, flexible contacts inside deform way too easily over time and you begin to lose one channel, eventually completely. This part, which solders directly onto the PCB, cannot successfully be opened up and repaired (I've tried - it self-destroys), and a replacement is hard to get, so next I'll be attempting to retrofit a conventional heavy-duty, unencased phone jack (something the latest v.3 appears to have switched to, judging from photos of its front panel), though I'm not yet sure I'll find the necessary clearance inside. You've been warned...
Head-Fi has some good owner feedback on nearly every headphone amp available. You might be able to find a direct comparison of the amps on your short list that will help narrow your choice.