@knollbrent I assume your phono preamp uses 12AX7 tubes. The big names I've heard are:
Mullard
Telefunken
RCA Clear Tops
A good place to begin looking for tubes is:
https://www.thetubestore.com/search?keywords=12AX7I'd also recommend that you login to the discussion forum that the tubes4hifi.com crowd uses:
http://dynacotubeaudio.forumotion.com/Those guys will have a lot to say about different kinds of tubes. There's also the DIY audio site:
http://www.diyaudio.com/What I find to be immensely rewarding is getting my hands inside the gear in some fashion. I've built loudspeakers off and on since the late 70's. There's little more satisfying than really being hands on with your gear. And you'd be shocked at how good the right DIY designs can be.