Tubes, old and new

I sat down next to Tim Pavaracini in a room at T.H.E. Show in Irvine weekend before last, and listened to him talk about tubes. He told me that in the 50's and 60's the various tube companies would swap tubes amongst themselves when they ran low of a certain model, putting their own logo on the glass of a competitors tube. It would therefore behoove tube enthusiasts to learn the internal physical characteristics specific to each make, especially when spending big money on them. Tim's personal favorites are Mullards. He had nothing good to say about ANY tubes being manufactured today, feeling the guys and gals on the tube assembly lines have not apprenticed long enough to learn the skills necessary to build a quality tube, that they are not career professionals, but merely temporary employees. Buy your tubes from an honest, knowledgeable tube vendor!
Everything which was done from engineers in that time was for professional use and there was also a lot of competition. Reliability, heat management was a serious chapter on its own. The comeback of tubes is for High End only with all its negative facts (cheap production, lousy wires inside, marketing, Distributor chain, no real knowledge from the modern buyers, too).
On the other side, some NOS are really expensive, real NOS became rare and even burned down tubes with a famous name are totally overpriced. And it is normal that all those who deal with old tubes have only bad words about new ones. In a way they are responsible that for some old - expensive - ones the price went down.
Compared to these prices the new ones are ok. And as usual, you find from everything average, good or better ones. It is the same rule valid like for all "High End" products: when no one has a clue from something, you will get products where the manufacturer says: It is good enough for you. Be it Turntable, Arms, reissue vinyl, Phono Stages....and so on. "They fix it in the marketing".
And the Chinese (and others) do exactly that and not for a dime more. Russian Jet Fighter tubes are the way to go when you want something serious for a fair price. But unfortunately, they did not use 300B, 12AX7....
Yes, back in the heyday of tubes manufacturers put their labels on tubes made by someone else, but it wasn't with bad intent. Tubes cost a couple of bucks back then and most people didn't care if they had an RCA or a Mullard in their tv or radio.

It's not too hard to determine what tube you actually have these days.

Phillips tubes (Amperex, Mullard, Siemens, Valvo and many more) have codes etched into the glass. A list of the codes and how to read them can be found here:

Telefunkens have a diamond molded into the glass at the bottom between the pins and RCA etched an octagon around the tube variety (e.g. 12AX7) into the glass near the top of the tube for a couple of examples of identifying characteristics.

The Tubemonger has a huge library of photographs of vintage tubes that is very helpful in identifying tubes.

Of course, scammers have found ways to counterfeit many tubes and there can be subtle differences between a top shelf tube and its low shelf relatives, so it is best to buy from a reputable dealer rather than try your luck on ebay, probably cheaper in the long run too. A good dealer has a lot of experience that is invaluable.

I do enjoy learning about tubes and their various qualities, though.
You're welcome Bdp24. You are most likely to see Phillips tubes with the "New Code" etched into the side of the glass near the bottom (top drawing at the bottom of page 3), using the top two "Examples of "correct code" format." So you can skip all the stuff about the "Old Code" and other code formats. It's not too hard to figure out the codes but if you have any questions feel free to ask me.
Tubes are best understood and appreciated by listening to them in a system, not listening to them talked about by experts. As soon as anybody spews a blanket statement regarding new tubes being somehow universally inferior, they lose credibility immediately regardless of their supposed expertise.
I think that's a pretty safe assumption! Kavi Alexander had Tim design the tube electronics for the microphones and tape recorder he uses to make his Water Lily albums, some of the best recordings ever made. Roger Modjeski says Tim is one of the other (beside himself ;-) engineer/designers working in Hi-Fi he respects. An unsafe assumption is that I spelled Tim's last name correctly (it's actually Paravicini), even though it's right there on the faceplate of my EAR 868 pre-amp. Duh.
I don't question his reputation as a designer as I like his stuff…I simply think he's utterly wrong about modern tubes, many of which are superb.
Keith Herron, another good one, is with you on the subject, putting current Sovtek tubes in his products, which sound mighty good, and advising against substituting "better sounding" vintage tubes. Modjeski himself says a tube doesn't have an inherent sound, that what a circuit sounds like with any particular set of tubes in it is a function of those tubes performance curves (conductance, voltage, noise, etc.), not an inherent sound per se. I always listen to a products designer when using his product.
In my hifi I use NOS Mullard 12at7s (6201 gold pins) because they flame up on start and sound great (the flame up is important…not sure why), new Gold Lion 12Ax7s because they are built beautifully and sound great, and KT150s because they sound great and are unique. Old KT150s are hard to find as they never existed. In guitar amps I use a weird assortment of El84s, 6V6s, and 12ax7s…new Mullards, JJs…a potpourri as it were.
A guitarist, ay? What amp are those tubes in? The best players I've worked with favor amps like the blackface Deluxe Reverb and Vox AC30. Heard of Evan Johns? Great player, a Tele straight into a Deluxe on 10. Awesome tone! Drinking problem, though. Petty's guitarist Mike Campbell is buying every AC30 he can get his hands on, the glutton. I just sold my blackface Single Showman, a great bass amp.
Wolf, I'll have to try some Gold Lion 12Ax7's in my new phono amp---Keith put Sovtek's in it, but told me sure, try some others. I use GL KT88's in my power amp, they're good enough for me. Where'd you get the 12At7's? They're the other tube in my phono. I'm pretty close to Kevin Deal, I gotta make a trip to his place and see what he has.
I bought a pair of gold pin Mullard 6201s simply because I liked the 4024s so much…not a noticeable tone difference but I like gold pins for anti-corrosion purposes. The 4024s are safe in the backup role. My current fave guitar amps (after owning many, many amps) are a Reverend Goblin 15 watt 1X10 (Jenson Neo…great sounding little 100 watt 10" speaker with another one in a small box) with reverb small combo (they made 300 of these) with 6V6s in the output stage, and a really sweet monster Burriss Royal Bluesman class A single ended 18 watt amp with EL84s. Mesa 12 cab with that one. Lower wattage amps do the job for me as they bloom earlier without peeling the paint off of everything, but still can be loud if need be.
Wolf, how about those Tung Sol 5881 tubes for one of those geetar amps of yours, a favorite of mine in my preamp as a regulator, man are they musical!
If you go to Brent Jessee's site he usually has a bit of history behind the tubes and their provenance: who originally built them, for who, and if machinery was left that the newer ones use. It can be quite informative.

Also, I read somewhere (or was told by Jesse himself) that some of the metals used back in the day are no longer available due to their potential and illicit uses in weapons manufactoring. Newer tubes can be made to very exacting standards but they'll never quite sound the same as NOS. That's not to say they'll sound inferior, just different.

All the best,
I no longer use a 6L6 type guitar amp so 5881s wouldn't work…6V6 and EL84s for lower wattage amps these days.