Audio-Voice 12AX7A

I bought this tube as a spare for holes 2 through 5 (actually I bought four, because the Chinese factory doesn't make 12AX7 and 12AT7 tubes anymore). So I also tried this one in the gain hole. The most noticeable fact was that this tube sounds very direct, not exactly harsh or shrill, but loud, in your face. It produces very good clean sounds, but when playing lead and rhythm the amp sometimes doesn't sound like a tube amp anymore. The Audio-Voice may be great for other positions, but certainly not for the gain hole.

Information from http://www.fbk.eur.nl/BIT/MHM/gear/preamptubes.html

Sovtek 12AX7LPS

The LP stands for long-plate, the S for spiral (for AC filaments). There are stories about people returning this tube, because they didn't see the filaments glow and thought it was defective. People, use your ears for listening, not your eyes! But they were right, it is hard to see if the tube's functioning, I had to stick my head in my amp to see some vague glowing. And the sound? A lot like the 12AX7WA, but brighter, and that's a plus with all types of sounds. The lead still has that nasal feeling (good), the rhythm is still a little hollow (not so good) and the clean sound is very rich and clear. One time during rehearsal I noticed that this tube is more microphonic than the 12AX7WA. I bought a tube damper, but due to the LPS's slightly bigger size it wouldn't fit! The 12AX7LPS scores a better overall than the 12AX7WA, but they both have problems with rhythm.

Information from http://www.fbk.eur.nl/BIT/MHM/gear/preamptubes.html