Been wanting to do this for a long time to complement my Sennheiser 535′s. Links to plans:

http://www.techtv.com/screensavers/howto/story/0,24330,3405528,00.html http://headwize2.powerpill.org/projects/showproj.php?file=cmoy2_prj.htm – If you go halfway down the page on Appendix 1 you can see a amp built inside of an altoids tin. TIGHT. http://www.minidisc.org/headbanger.html http://tangentsoft.net/audio/cmoy-tutorial/ – Full tutorial including electronics basics, for construction inside a circular mints tin.