Headphone amps


I like to listen to music at night - my wife likes to sleep - I can't understand why she does this with so much good music to hear. Headphones have been a blessing for maintaining peace given our somewhat different nocturnal patterns. I'm soon getting a new integrated amp without a headphone jack, so I will require a little amp for the headphones. Please provide recommendations for headphone amps that you have used and loved. I like to listen to jazz and classical at night. I'm using a FMJ 23 as a source and I tend to like tube sound. I have Sennheiser HD 600 headphones.
johnrob
Sorry, I gave the wrong link in my previous post. That should be head-fi.org (not head-fi.com).

Jeff
Look at the Earmax (http://www.stoneaudio.co.uk/stoneaudio/products/details.asp?product=217) line.
Try this site. Its home to headphone lovers.

http://www4.head-fi.org/forums/forumdisplay.php?s=&daysprune=&f=20
I second the Earmax, especially the Pro. Swap out the stock tubes with NOS and WOW! I have the Sennheiser 600s and could listen for hours...and do!
I don't know about the matchup of my amp with the Seinheisser 600's, but my Berning Micro-ZOTL with Sony MDR-CD3000 cans is magic.

Definitely check out HeadFi for all your headphone questions.

Marco