As I mentioned earlier I was able to do some (completely subjective of course) listening with the Super PAS 2 (from Frank about a month ago) with various tubes. I have old Telefunken ECC83s, JJ ECC83s (new, short plate), Sino 12ax7s, EH 12ax7s, RCA 12ax7s, and JJ ECC803s. The power amp was a AVA U70, an AVA Omegastar 260EX, and a stock but perfect Dyna st-120. Speakers were B&W DM110is and B&W 803s. The sources were a Marantz CD5001 and a HK T-25 Turntable with a Grado Green with Longhorn. I didn't go in and set the Phono termination to 10K, but just left it like it came (presumably 47K).
Obviously I didn't try every combination but it wasn't that hard to tell the difference between the tubes anyway.
Sino and RCA - mediocre. The RCAs were old but had little use, and the Sinos were new matched pairs. Both had some noise and were really not in the game even with 30 seconds of listening. They were really bad in the phono section.
JJ ECC803 - bad. Very quiet but just didn't seem to work very well. Almost everything had a metallic "ring" to it and it may have been marginally damped or marginally stable, or maybe it was microphonic (although a "tap test" didn't show that). Gain was noticeably lower than others. Might require circuit changes to work best but it didn't work in a Super PAS.
JJ ECC83 - Very good. Very quiet, excellent linearity, excellent damping and definition - cheap
EH 12ax7 - Very good, DEAD quiet, excellent linearity, very punchy/powerful sound, very high gain- cheap
Telefunken ECC83 - Very good, not overly quiet and was marginally too noisy in the phono section. Worked very well in the line amp section, maybe slightly reduced definition - free because I already had them but expensive if you try to buy
Right now I would have to say I would probably prefer the JJ ECC83, with either the Telefunkens or EH as a close second. The Telefunkens are old and maybe that's why they have a little more hiss and a little less gain as a result, but at least IMHO they aren't any better than the JJ or EH overall. I prefer the EH in the phono and the JJ in the Line positions. The only problem I have had with the JJ is that I have had two (of four) go over the hill in the space of a month or so. That aside when they are working they work very well and either the EH or JJ is really cheap. The difference between the brands is so small that I am sure the unit-to-unit variation would swamp it. From this experiment (which is hardly comprehensive) you are not losing out of you can't get Telefunkens and to be honest I would guess you could buy a stack of JJs for the same total and sort through them to get the best ones, and wind up better off. The sound quality is a wash even with the examples I have. Who knows about the reliability, but I would be surprised if the JJ or EH were around and functional in 40 years like the Telefunkens. Just buy a bunch of spares.
I would also note (like in the other thread) the Super PAS itself is outstanding. Of course it's dependent on the tube quality but it's as good as anything I have heard regardless of cost ($20,000 for a CJ? PT Barnum would have loved it). To be honest with you, I was more than a little surprised at how good is was. I figured Franks take on 12AX7 amps would be better than average, and a stock PAS 2/3 in good shape is a pretty decent preamp but I was blown away by how good the Super PAS is. Overall it's as good as the Omegastar although a little different here and there.
Brett