Rolled some 12ax7's recently...

B-man, we were all beginners once, and although people have to have their own learning experiences, it doesn't hurt to ive folks a little heads up.

As for current ('reissues') vs. NOS (honest people now call them ANOS = almost new old stock = slightly used old stock ;-) Honestly, slightly used is a better bet than brand new old stock because at least the slightly used are proven working. If I were buying expensive BRAND NEW old stock tubes, I'd make a deposit but then insist the seller
test and burn-in the tubes for a few hours before shipping them to me ;-)

As for their sound, the current issues aren't bad, and I'm sure they will slowly get better. The brands bought by the American fellow who owns New Sensor in russia are: Sovetek, Genalex Gold Lion, Electro Harmonix, Svetlana, Mullard, Tung Sol, and a few other I forgot. None of them are like the originals (internally) although some are built very substantially.

The real difference between the old and new is metalurgy. The old-timers who experimented for years and years cooking up new (secret and jealously guarded) plate coatings had no one to pass the secrets to when ss came along. So the craft died with them. They succeeded in achieving very high plate current at rated voltages that tubemakers today can only hope they'll get to one day.

As an example, a typical NOS Genalex GEC or Gold Lion had transconductance values (when new) of 10,000 umhos or more (that's the measure of a tube's gain). Today's best KT-88's, the Genalex or the Shuguang/Penta-Labs (the Penta is an exact copy of NOS tube) when they are brand new are 7000 to 7500. I have some USED NOS Genalex theat are 9000! So it's not so stupid to buy he older tubes and some of them have a sparkle to them than so far no current tubes can duplicate. Anyway that's the basic story. There's tons of history and lore available today at the click of a mouse.
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Great information Nsgarch, thank you!

Yes, it does appear that many older tube varieties have very fragile printing on them. My telefunken ECC83/12AX7s barely have any markings left, just from handling. I am fairly careful handling the ECC803S which were never used (cam in very nice looking boxes, though the cardboard has become somewhat fragile). My Bugle Boys also have somewhat fragile printing.

Because of all of this discussion, I did something I rarely do (being quite lazy), which is to switch out the ECC803S and replace them with the ECC83. Where my memory was that the ECC83 was more "muddled" sounding, that turned out to not exactly be the case. The ECC83 is not really more muddled or lacking in clarity, it is more the case of transients (initial attack of the note) being softened, as compared to the ECC803S. I still prefer the ECC803S, but again, the price differential is striking.

I should also mention that, in another friend's system, the Bugle Boys sounded terrific in the phono stage of a Hovland preamp -- so much more lively than the stock tube that came with the preamp.

Larry, one day I just said, "this really sucks!" and I got some Q-Tips, gathered a few old European tubes that had almost no printing left, and set out to try every solvent I could think of to see if anything would spare the printing. Naphtha was IT. And no surprise really -- that's the only solvent dry cleaners will use on your clothes!

I should have noted that even the moisture in some peoples' skin can take off the printing, so it's best to handle those with really fragile (almost gone) labels with a clean cotton cloth or latex gloves before and after cleaning.
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It seems many are raving about the RCA 12ax7 black longplates, but I've barely seen or heard a word about the RCA 12ax7 GRAY longplates. I've owned and listened to both varieties in my system. I just shook my head. I wound up selling the blackplates.