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

@whart , I know what you mean about Andy. I once placed an order and he called me 18 months later to fill it, haha. Sorry, Andy! I’m pretty sure KR Audio is still operating. The 5U4G I’m talking about (actually called Riccardo Kron Anniversary Edition) had a brief production run, I believe in 2018, so they ran out a while back. But they do pop up for sale. I found a new one 7 or 8 months ago on AudioMart.

I love tube amps and have learned that the worst thing you can do with one is turn it on and listen to it. Sure, it might sound great, but that leads to tube rolling from the audio geek compulsion to change stuff, and wear and tear on the tubes. Just put the amp there and leave it off...you can still look at the tubes and feel like you know what you're doing and are part of the tube freak world. But by no means should you actually use a tube amp...it will just lead to trouble.

@inna Sorry to be so late to this. If I may add a humorous aside?

Keep anything long enough and by default it will become "vintage". 

IMHO, much like the halo around "Cuban cigars", I think that "NOS" tubes are somewhat overrated. "Old" doesn't necessarily translate to "better". Yes they were "made differently" back when, but modern materials and manufacturing methods are unnecessarily demonized. Let your ears be the judge.

Happy listening.

@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.  

My preamp is Conrad-Johnson's top model the ART88.  It came brand new from the factory with four Phillips NOS ECC88's.  I read in a HiFI+ review that you could replace the "made for TVs" NOS tubes with EH6922 Golds for a nice increase in sound quality.  Okay, so ordered a set.  Yes the change was immediate. Jeff, the designer at C-J said he thought the EH's might turn noisy but no harm.  After a few months, there was no noise from the EH's but thought I'd put the NOS tubes back in and see how they sounded.  What I discovered was a definite preference for the original NOS tubes.  The sound was better; richer in the mids and just as detailed.  Turns out, I was fooled by a bit of extra gain from the new production tubes.  Slightly louder, of course, sounded better at first.

Guess the process is to listen and see what you prefer.  The HiFi + review has  different gear so came to a another conclusion.