Thank you everyone!
My audiophile headphones have been gathering dust lately thanks to my 2 (noisy) young kids. Hopefully, I'll be able to listen to some music tonight.
ECP Torpedo III with 12au7 tubes and the low impedance output setting has -6dB gain:
http://www.diyforums.org/Torpedo-III/TorpedoIII-tubes.php
You can do the same thing with the Torpedo 4, but I'm not sure what the gain would be exactly:
http://beezar.com/pho-bzr/catalog/pub/docs/Amplifiers/T4/T4-FINAL.pdf