I have a few questions about getting other tubes for the Aune T1.
1) Am I correct in thinking that I can use 6922, 6DJ8, 7308, or PCC88 tubes with this device?
2) Upscale Audio (where I've been mostly looking) sells three different grades of tube. I don't think I need to worry about microphony with the tube application here but I'd love if someone could confirm that.
1) You can use the 6922 tubes and their derivatives with this DAC/Amp.
2) I picked up 2 additional tubes for this per this thread (http://www.head-fi.org/t/633006/aune-t1-usb-tube-dac-amp-discussion-thread-see-first-post-for-faq), specifically some NOS (New Old Stock) that are Voskhod 6N23P Rocket Logo's and Reflector 6N23P-EV Military spec tubes. I use the Rocket logo for listening to music and the Relflector for games since the bass response from the Relfector is more distinctive than the Rocket (this tube is very warm all over and responds very well to classical and any music that is not heavy on bass beats).
Correct. They are all the same tube family but differ in quality and sound.
You can also use 7DJ8 and 6ES8 tube families.
All of the tubes carry a different name in Europe. Check out radiomuseum for that information.
6DJ8 = basic grade
6922 = improved grade
7308 = highest grade
Microphony is not an issue with these tubes.