But the price of NOS tubes is not justified....besides which most NOS tubes are fakes.
Most NOS tubes are just old used tubes which have been "tested." Not really NOS at all.
And most of these old tubes are actually junk.
After having gone through a bunch of these "NOS" tubes, it's not worth it.
But really a 12AT7 will probably work just as well as 5751.
Whether or not the cost of NOS tube is justified or not is dependant on, among other things, ones perspective & exactly what type tubes one is buying for what application/amp. We'll come back to this later.
To answer the statements starting with "besides which most NOS tubes are fakes" & ending with "and most of these tubes are actually junk."
Mate, I buy NOS/NIB tubes. Many of the tube types I buy I have previously used (some quite extensively) when they were still in production, and I've LONG been able to tell a used tube from a new tube. I've not once, ever ever, bought NOS tubes that weren't "exactly" what they were supposed to be, "unused new old stock tubes." Nor have I ever bought NOS tubes that turned out to be "fakes" or "junk." Oh, & by the way, I have posted pics of some of my NOS/NIB tubes on this fine forum on several occasions.
While there are scammers out there, it comes down to either knowing your tubes, or knowing the supplier to be trustworthy, or better yet, both of these.
As to the statement "after having gone through a bunch of these "NOS" tubes, it's not worth it."
Mate, that's a pretty broad statement to make, especially as you've not even mentioned any "type" of NOS tubes that you've been through. Considering that you've trashed NOS tubes here a few times, surely you can show us all some pictorial evidence of these NOS tubes you've bought that proved to be "not worth it" (your actual NOS tubes, not pics pulled from the net)???? And the amps you tried them in???? Or are we simply meant to just blindly take your word for it??
Getting back to where I left off by saying "we'll come back to this later", I have previously asked you this same question after you had trashed NOS tubes here on TTR, you didn't reply,,, so I'll ask again.
Can you tell me of ANY current production EL34's that can give 10,000 plus hours service life in an amp like my 67/68 JMP50 (no screen grid resistors fitted)????
The double halo getter xf2 Blackburn Mullard EL34's have proven to do this, they've been known to last decades.
That alone, IMHO makes seeking out & purchasing these type NOS tubes very much "worth it" for such an amp.
Then there's the sonic benifits, which, "in the room" with the amp, you'd have to be deaf not to be able to discern.
Cheers