If NOS pre or power tubes became unavailable altogether, what new tubes would you buy?

Dear @cleeds :  """  everyone here should be entitled to their preference without you telling them that what they think does not matter.... """

that's exactly the whole " thing ". Preferences does not matters what it really mathers in a home audio system quality performance level is at what " distance " is that performance level of the way ALWAYS sounds the live MUSIC at near-field position. How much is far away or nearest to.

Of course that almost all are enttled to preferences even if those preferences are way different on what is in the recording or how the live MUSIC sounds ( full of colorations that were not in the recording but generated by the home audio system that through tube technology are even higher than with good today SS designs. This fact can't be changed for any one, like it or not. ).

You read in the other post here where I name it distortion sources that normally no one really talks about when we are talking of differences or evaluations  and the why's of those differences with different audio items that are critical especially when we are " testing " tube vs SS. We can add others as: low and high frequency oscillations levels, RFI and EMI interferences even if in an audio item both channels measures exactly the same in the normal specs and in all the ones I posted  in this thread.

There are something for sure: WHEN AN AUDIO SYSTEM PERFORMS WAY NEAR AS A LIVE MUSIC/RECORDING THERE IS NO WAY THAT ANY NORMAL AUDIOPHILE DISLIKE THAT QUALITY PERFORMANCE LEVELS IN FAVOR OF HIS PREFERENCES. 


"""  the way you insist things "MUST BE" just isn't. """


Why not?  am I wrong? why and where?  which or where are the mistakes from my part? how " things " should/must be?. I really want to know those answers with out " touching " preferences that as I posted ( again and again. ) it does not matters. MUSIC is the only subject that really matters.

Regards and enjoy the MUSIC not DISTORTIONS,
R.

Dear @rauliruegas
Disregarding our differences on tube v. s/s, and assuming no-one has built the "perfect" anything linking source to ear, I'd ask your opinion on what you regard as the closest to perfect you've heard, irregardless of price, and same question for one on a budget of, say, <$20,000 (give or take). Thanking you in advance,
deepee99

@rauliruegas --I'm not sure it is helpful to offer opinions about solid state v tube here. Many of us use these forums for information gathering.  If someone has a genuine interest in the title and subject of this thread, they will come to the thread and see lengthy discussion on different subjects. 

Also, I don't know why you dropped in just to knock the technology at its core. I'd have these same issues if a tube head dropped in to bag on solid state amps where the underlying discussion was about preferences within that technology. 

For what it's worth, the CV181 is NOT electrically equivalent to a 6SN7.  If you replace a 6SN7 with a CV181, it is bound to sound different, because the CV181 is operating at a different part of its performance envelope.  But people do it.  Have fun.

Raul, I think one reason that SS has taken a back seat to tubes at the higher end of the audiophile spectrum is that most of the SS gear to which we are exposed is built to a (low) price point, and if you look inside, you see crappy capacitors, bad layout, fail-safe circuit designs, for example using over-size electrolytic coupling capacitors, that assure mediocrity.  There are only a few SS products built purely for max performance with cost no object.  Perhaps you should start a thread to discuss this phenomenon and name some of the best SS products currently and previously available.

@lewm,
Thanks for clarifying that not all 6SN7 *types* are identical. I was merely trying to assure him that he wouldn't be applying plate voltage to the grids or heaters. Electrical variations (as I mentioned) do vary from tube to tube. Of all the 6SN7 types there's only one to be leery of and that was a mil-spec RCA VT-231 that pulls significantly higher filament current and could stress the x-former tap. 
Yep, it's important to find the tube's idea point on the curve, which depends on your circuitry. I (and the design used in VTA/Tubes-4-Hi-Fi gear like about 45% for the 6SN7s I use but it's not a magic number. I sure wouldn't go much above 65-70% for such a low Mu tube.
If John Bedini could build the "near perfect sounding" amp out of sand components 30 years ago, I am sure there are ss pre-amps and pwr amps out there I'd like better than my tube lash-up. But as you say, most of the new stuff has crap fail-safe circuitry and cheap parts. Even on the tube side a lot of very expensive production gear uses junk. Why McIntosh went with the EH tubes in their driver section I'll never understand, when for a few bucks more . . .
As to s/s vs. tubes, that horse has been beaten to death. Whether tubes or s/s, the sound is going to be far more flavoured by preamp components and the amp's driver section than the honkin' amp, at least according to the all-knowing myself :-), and might be worthy of a thread if there ain't one.
Cheerio,
-d-