Would you buy a tube amp if you were unable to use vintage tubes in it ?

I'd ask the opposite question- does the unit sound good with a modern production tube? Good old stock is depleted and pricey- yeah, I run them but it gets harder to source replacements. And in my experience, there is a big difference in sound among different tubes that are semi-equivalent if not directly equivalent. So, I'd want something that will play nicely with a readily available tube, not just unobtanium, if I were in the market for new gear today. And, what is readily available today may not be tomorrow. I've been using tubes for audio since the early-mid '70s. If I were starting from scratch today, I don't know that I go down the rabbit hole at all, but that's wishful thinking-- I am where I am. Enjoyed the journey. Appreciated the days when you could buy new old stock Tele 12ax7s for 10 bucks a pop-- which was considered a premium. 

@bigtwin I think the answer was supposed to be the transistor but I've been around long enough to remember how much better the ARC SP3 preamp sounded than its solid state competition in the early-mid '70s. And, insofar as tube manufacture is concerned, I think it is a combination of things: materials and worker safety, tooling and loss of know-how for what is at best a now a niche market. That tubes were still manufactured in the old Soviet bloc had less to do with their belief in old technology than it was their inability to modernize. Sure, there are similar issues with rare earth materials involved in semiconductor manufacture, but the tube is obsolete and as such, people go back to the days when they were still a mainstream product. Did you ever see those old newsreels on video of the production of Mullard tubes? Fascinating- it was like a steampunk assembly line.

Here's one: https://www.youtube.com/watch?v=GDvF89Bh27Y 

@wmr57- my doppelgänger--you still using the Allnic phono pre? I rolled a bunch of rectifiers in that, finding the sweetspot for me, given my system voicing, to be the GEC U-52 cup base. I have a metal base Mullard (really a Philips-Miniwatt from Holland), a grail tube, but it had mucho bass and no "air" or nuance on top. For those unfamiliar with the unit, it is supplied with a cheap, crappy rectifier (or at least it was) and I suspect the manufacturer knew that folks were gonna roll it. It’s really the only tube that makes a difference in the unit.

@inna- with respect to Lamm, they supply a Sovtek 12ax7 as part of the full tube complement for the ML2 series SET amps when you buy from the company, which most do. Those usually get rolled by owners. I asked Lamm about it once- they didn’t really go to the trouble to source NOS 12ax7s  (though a lot of the tubes in the amp aren’t new manufacture--you take your chances on the power tube/regulator Russian 6C33C which you can buy cheaply in the open market but there are risks of failure and those tubes have a weird range of bias that corresponds to each amps range for biasing them, a factor that Lamm keeps proprietary). The only tube I "roll" in the Lamms is the 12Ax7 and use an old stock ribbed Tele, which gives the amp a little more bite than the smooth plate. Both versions of the Tele sound far better than the Sovtek. 

As to wide availability of common tubes, like the 12AX7, you can buy "pulls" of that tube all day that measure well. My experience is that they don’t last as long and go noisy. True NOS isn’t cheap if you can trust the vendor and my experience is that the amps hold bias better too. (Use a Fluke pretty much every time I run the amps to verify). 

In a world where tubes were common and easy to get it was fun. Now that a lot of these are unobtanium--try finding NIB GEC KT66s as a quad (I did some years ago for my Quad II amps), it becomes another hurdle. I’m not in this for bragging rights, I’m in it for sound, which is why I suggested that modern tube amps that will sound good using readily available modern production makes even more sense today, with the depletion of stock. 

@wrm57- not a problem. I mistyped your screen name earlier. I did find another cup base GEC U-52, this time a black base, not a brown base. I think it is an earlier production, although someone else who had a lot of these said that the brown base was preferred (my brown base tube still has some life but had some time on it), and the fresh black base sounds fine. Doesn’t surprise me that Kron is not readily available. Are they still in business?

When I retubed everything (all components, not just the Allnic), I did get old stock Holland E810Fs. I had bought some a few years before, never used them, but they were printed on the glass as made in Great Britain. I later learned they were made by Amperex in the States. Apparently, during the golden age of tubes, affiliates took overflow and since both were owned by Philips, no problem. My seller was surprised to learn that- I didn’t return them, they are in one of those boxes of "fresh" old tubes stashed away here.

Even having been in this market for decades as a consumer, there is a lot to learn and nuances that aren’t obvious to the uninitiated- all the more reason to source tubes from a trusted seller. Andy is one of the best I’ve encountered in the States since the Great Disappearance™ of Elusive High End Tubes, but you have to be patient. He can’t always scratch the itch when you need a tube, pronto. 

@musicfan2349- I was pretty picky about my cigars too and probably had more depth in those at one point than in NOS tubes (which have all kinds of nuances re where manufactured, when, getter, and other internals and I only have knowledge of the tubes I've used).

The benchmark for me was a spicy smoke that wasn't harsh- I was able to experience everything from pre-Embargo to Davidoff cubans, and my go-to was a good Monte #2 but they were variable (I guess b/c they are organic, but I don't know if wine connoisseurs find bottle to bottle variations; that was certainly true of cigar batches, leaving aside "vintage"). Alas, I had to give up smoking many years ago for health reasons so have no clue what that market is like these days.