6922 tube recommendations

A couple of years ago I purchased a Musical Fidelity x-can headphone amp. I followed MF's directions and left the thing on all the time, and eventually the tube burnt out. I bought a cheap replacement and it sounded like crap. Specically it had way too much noise to be enjoyable at moderate volumns. I basically haven't used the amp since then.

Given that my wife has been busting my chops for playing my music too loud at nights I was thinking of bringing this amp back into the rotation. However, I need to replace the tube before even considering it. Does anyone have a recommendation for a good 6922 tube? tried searching the forums w/o much luck.

thanks
Sballs