Headphone amps HD what are the choices?

You should check

www.headfi.org
www.headwize.com
www.headphone.com.

The first two are forums and information sites. The last site is Headroom's commercial site that also contains loads of good information. I personally have an MG Head DT tube headphone amp as well as a Headroom "Little" amp. I use my HD-600's with both of these amps and am quite satisfied. Would be hard to choose between them, because they are very different amps. If you are running sound out of a computer, then I assume you play MP3's more than CD's. The MG Head DT, though very clear and tight, might be slightly more forgiving of the lesser quality sound of MP3's. Another budget priced amp I have heard great things about, but never heard, is the Corda amp, at

http://home.t-online.de/home/meier-audio/

Jan Meier, the guy who runs this site is great to deal with. I bought some AKG 1000s from him. he probably has the best deals on Sennheiser stuff too. His store is in Germany but his site is in english and the shipping here is surprisingly quick.

Good Luck

hi!
i never run any MP3 at all
only CD DVD soon DVD-A and HDCD

and then digital in from PS2 and satell dish

the card will outputs really high quality sound ( waveterminal 192X or terratec dmx 6 fire )

but at that price the amp shouldn't be too much in used
...

what other choices do i have in the used amp market?

and how much will cost replacement tubes?

Corda Headamp.

Generally, depends on your tastes and $ to spend, but I second the MG head recommendation (Antique Sound Labs) - very good headphone OTL amp.

It combines very well with the HD600.