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

I have enough tubes until the next ice-age.Thanks for asking!!

Dear @tubed1 : What do you think is the real difference in quality performance level between your home audio system and almost any other one?:

mainly the DISTORTIONS levels of your system against the others. 

Regards and enjoy the MUSIC not DISTORTIONS,
R.

"DISTORTIONS" Sur contrarie El Diablo.

Dear @lewm : Not even in the 60K electronics you will see teflon cooper V-caps or naked 2575 resistors. Manufacturers as ML makes very good designs: industrial design type, militar specs parts, bullet proof design type. Even that they do not use " boutique parts " they choosed carefully through proved trusty ones: takes no riscks.

Many of the names I posted design that the active parts stay working at no more of its 40% posibilities, especially those pure class A designs where temperature ( to hot. ) is a real enemy for those parts where the quality performance could " suffer " changes out of specs because that kind of temperature. They design for years to come working in those " hard " conditions. SS designs are really trusty and performs faultless for many many years.
When a trouble is present it’s not easy to fix it as with tubes where you just change one tube and that’s it, always is more complex in SS designs.
My ML 20.6s is very good example about: came fromm more than 25 years and works in pure class A and I play with every single day and never had any single fault: staeady all these years as if were manufactured two days ago. This is SS technology.

The important subject is that if we take the SS path we have to, step by step, re-set the system around the SS electronics understanding the SS whole path. Especially its advantages when we compare it against live MUSIC.

Regards and enjoy the MUSIC not DISTORTIONS,
R.

Dear @lewm : ""   you see crappy capacitors, bad layout.... ""

well, bipolar transistor can sees as 2-3 dollars crappy parts and with out knowing the designer targets ( even if at a low price point. ) is not easy to talk about " bad layout ".

SS designs are way complex than tube ones and SS always has a lot of parts ( sometimes over 100+. ) but signal does not pass trhough it but only through at minimum of it. 

Today decent SS designs can't performs bad and I listened some of them as: ( @deepee99 ) Ayre, Simaudio, Parasound, Naim, Classé Audio, Gryphon, MBL, ML, Krell, Dartzeel, Chord, Sutherland, FM Acoustics, Boulder, Pass, Rowland, Bryston and to many that's not useful to name it here.

As @tomcy6 posted nor two sounds alike but different because design, excecution's design and parts are different as is each one price.

Now, if we change only one link in our system: say preamp or amp, we can know for sure nothing of what I posted here and elsewhere.

To really learn inside the SS alternative we have to choose both links: phonolinepreamp and amp and we can do choosing from the same SS manufacturer.

As I posted here first premise that we have to acomplish is start from CERO and not wanting or comparing if those first impressions with SS are away or near the tube alternative that's what we were accustom to for many years and that's what we like it.
NO, we have to " close " our listening memory of all past tube experiences. As we never had it.

Then focus for at least 3 months in the SS alternative and attend as often we can to listen live music in a nearfield fashion.

The SS learning process is not only made the electronics changes but, step by step, we have to evaluate if the system/room interactions stay the same or we need to make some chnages " here and there ", we have to evaluate if the speaker position is fine or we have to move or toe in in different ways, we have to evaluate if the cartridge VTA/SRA needs a re-set, we have to know if the IC/speaker cables honor the new system surrounded enviroment, etc, etc,. It's a " long time " approach " not plug and play one. We have to learn to listen with that evaluation ( bullet proof. ) proccess I mentioned in this thread.

Through SS electronics everything ( the good and bad. ) in the system comes out, there is no " room " to hide the system tweaks as with tubes. So, it will comes more revealing and several times we do not like the " true ". We have to be prepared to assimilate it an know what to do or what to change to fix system's errors/mistakes/colorations/distortions ( you name it. ).
Could be that the system with tube electronics like itg because is not overbrigth and dislike it because with SS now is overbrigth and we are tempted to say and think: " SS is brigth when in reality it's not but maybe the speakers it self or other system's link in that complex chain.

Your usual words as: musicality, softness, non-agressive, organic and the like will not appears any more in your new SS based home audio system and you will start to compare its quality level performance with true nearfield live MUSIC.

Btw @tomcy6 we never know what a recording it supposed to sound like ( only if we were during it. ) and we don't need to know to know we are nearer to with SS than with tube ones because the SS way lower colorations/distortions of everykind.

We can't have every single answer till we try it in more or less way I explain here and no we don't have to go with Boulder or Dartzeel to acomplish in the rigth way. Ayre, Simaudio, Parasound or Classe can shows us. 
Again, we only need the rigth and positive attitude to do it seriously in an unbiased way.


regards and enjoy the MUSIC not DISTORTIONS,
R.

@enginedr1960I I think the only thing Raul gets me thinking is that he's a poseur: His strong opinions are not backed by any experiences he cares to share. There is no "one-size-fits-all" perfect signal path out there, or we'd all have one and there would be no need for discussion or chat rooms. The very subjective nature of the audio experience is what leads to such a multitude of opinion.

Should be under amp/preamp thread!!

I stock-piled enough to outlast the life of the amplifier (and perhaps me as well).

I understand that and do . My system has 4 tubes the phase inverter tube a 12at7 type makes the biggest change in the tone . I use a SS digital pre with a TVC volume control . I like having a one tube roll

One thing about Raul is he can make you think . This is a tube rolling thread after all . The question I ask myself if different tubes sound different then maybe he is right . I know it is nice to use tubes to change the flavor to our liking but is it a true accurate representation of the recording ? I don’t think so . We must ask again do we want the truth or the euphoric pleasant distortion ? I too am using tube amps and love the way they sound but I am tempted to try a SS amp I am considering a Benchmark ABH-2 . At least I wont sweat in the summer .

@rauliruegas 
If you can't identify at least one piece of gear you believe is better than whatever other piece of gear (or better yet, the entire signal path) you've heard, as I have asked you for, then I suggest your opinion reflects the depth of your experience. C'mon, give it a try. I won't flame you. I just want to know what experiences you are basing your opinions on. Perhaps I will learn something.

My mistake, it has to be this way.

"  we can't have a true valid opinion if we have not valid experiences. "

R.

Dear @jbhiller : No one has to worry about tube sources because always exist better alternatives that are almost really unknow for many of us and that's why I posted here.

Is clear that many of us want to stay sticky on tube electronics and maybe because many of us already losted the " adventure " esprit of a human been. Looks like many of us already losted the " quest " to find out what to do and how achieve a true better system quality performance level in favor of MUSIC.

Certainly rolling tubes is not a true answer to but try to learn how to look for true answers.

This is what a gentleman posted in other thread :


"""  the most accurate phono cartridges sound more like good digital . This makes me think some people do like pleasant distortion  . Remember ignorance is bliss until you have heard the difference . """


" until you have heard the " true " difference ": we can't have a true valid opinion in what we have not valid experiences.


Regards and enjoy the MUSIC not DISTORTIONS,
R.

@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-

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.

@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. 

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

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.

rauliruegas

Tubes are just with out any single way to deffend it other that what you are accustom to that is wrong and it does not matters that you like it because as I posted: what we ike does not matters, what matters is HOW THINGS MUST BE.

It clearly drives you crazy Raul that the way you insist things "MUST BE" just isn't.

Sorry, but everyone here should be entitled to their preference without you telling them that what they think does not matter. Geez.

The initial post is not Tubes vs SS but "what would you choose as new production tubes if NOS disapeared". Good music can be obtained ind with both. Technologies thanks god.

At that time I still have nos tubes, pre and power in my pre and amps, but a friend of mine curiously likes Sovtek 12AX7 LPS.
My Air Tight pre came equipped with them for the phono section because they are silent. I changed them with 5751 NOS for the best, but it is me.
12 AU7 Gold Lion have good reputation too (not cheap however).

Dear @tubed1 :  """  almost all of us belongs to that HE-community/AHEE... """

of course we do. That statement I posted in this and other forums " thousands " of times. We are in agree here.


"""  my ears are the "corrupted AHEE" """

NO, your ears are not. You learned through the corrupted AHEE but your ears are not corrupted because the AHEE take advantage of all of us high ignorance levels but we in anyway are corrupted or form part of the corruption.

As I said I'm still inside the AHEE but with a very big main difference than you: from some time now my audio choices/decisions are taking by me and not as you where that AHEE already took in advance for you. You are only a docil follower that go  for the audio world with out questioning no one not even your self or what you learned.

"""  alive and growing up!. """, alive is true but really growing up when you are severe limited by them?. You can't grow-up till you make your self one simple question: WHAT IF WHAT I LEARNED IS WRONG? and other questions: WHY IS WRONG? and WHAT CAN I DO TO FIX IT ?

Btw, """  Nandric/Dover  """?  whom are they? but people exactly like you that all what they learned is wrong. If those kind of people are the ones that support you then I understand your post.

Regards and enjoy the MUSIC not DISTORTIONS,
R.

Dear @deepee99 : """   Everything distorts,... """, agree and this fact is the main subject.

Now, there are more kind of distortions than we even can name it or even know about. We know about distortions as: THD, IMD, clipping/overload generated distortions, Fim distortion, etc , etc. but exist other kind of distortions that normally almost no one name it as distortions examples of these could be:

- Inverse RIAA eq. deviation level, item frequency response bandwindth, item slew rate, item headroom level, item output impedance, item type of amplification class operation, feedback levels used in the design, item noise level figure, active or passive gain in phono stages, damping factor figure, common mode rejection, crosstalk, dynamic range, etc, etc.

All those parameters and many more makes a difference for the better or worse and contribute to generated distortions additional to the " normal " ones. Tube designs are and have inferior way inferior figures that a good SS designs.

Tube just can't do it, it's fully limited technology ( between other things. ) at both frequency extremes that are the frame of the MUSIC in a home audio system, it's where MUSIC belongs and not to mid-range as almost any one can think.

Tubes are just with out any single way to deffend it other that what you are accustom to that is wrong and it does not matters that you like it because as I posted: what we ike does not matters, what matters is HOW THINGS MUST BE.

Regards and enjoy the MUSIC not DISTORTIONS,
R.

Everything distorts, from your gear to the room to the shape of your ear to the engineers and mics. I believe well-designed tube gear distorts best to my liking; with the close exception of a well cared-for S/S Bedini, it's preferable to SS distortion.
As to NOS v. modern issue, I've never had the pleasure of the Hammersmith KT-88s, but have had my run of antique NOS TS-6550s, Mullards, Brimars, Philips and the like, and the modern stuff from eastern Europe and Russia.
I believe the Chinese have gained the upper hand in sound quality for KT-88 type tubes if you stick with PSVane or ShuGuang. Both have factories in Changsha. My favourite of that lot is PSVane's top-end Mk II Treasure series. As for signal Tubes, PSV's top-end CV-181s will blow the skirts off any 6SN7 tube, NOS or otherwise, I have ever heard. But they're big bastards, almost as large as output tubes. so that's a consideration. 

Dear @enginedr1960 and friends: Comparison means not a few hours but at least 3 months in a row with full SS sytem and then come back to tubes and compare it. In those months is very important to attend as often we can to listen live MUSIC in a nearfield situation, this nearfield issue is important because is the way the recording microphones are in place during it and the target is to be nearer to the recording nearer on what the micros pick-up.
To make a serious comparison is critical to have a proved/bullet-proof whole evaluation process and to know in specific what to look for during those evaluation tests.

The tube overall subject is a very sensitive subject every time I " touch " it and the problem is mainly because many of you are living for many years in the " tubes's ghetto "  ( the only difference is that there don't kill you, only kills the MUSIC. ) where you never ask to stay there the corrupted AHEE just put all of you there ( in the same manner I was there for years. ).

All the ones inside that ghetto are victims of but all of you have a true advantage over the second world war: you are totally free to go out and I know sooner or latter all go out and the corrupted gentlemans that are the owners of that ghetto will pay for what they did it with all of us.

We only need to learn. They take advantage of our very high ignorance levels in that subject and that's corruption.

Btw, @toddverrone: you are rigth but I never said invented nothing and about the " horse " that's a privilege that each one of us have. never mind, agree with you.

Regards and enjoy the MUSIC not DISTORTIONS,
R.

There is no modern day equivalent to the NOS Hammersmith code Genalex KT-88.

The most consistent new tube I've used over the past 8 years has been Shuguang Black Treasure ( KT88, CV181-z, 12AX7 LS ) and Psvane (12AU7, 12AT7).

Shuguang Black Treasure:
http://psvanetube.com/wordpress/purchase/shuguang-treasure-series-vacuum-tubes/

Shuguang Custom 12AX7 LS, Psvane 12AU7, 12AT7:
http://psvanetube.com/wordpress/category/review/feedback/

@rauliruegas that's great you posted things here first.. you didn't invent them, though, so get off your high horse. 

Dear friends: All of you are rigth and I truly meaning ( I'm not trying to be ironic. ) it.

It can't be other way because that's what you " learned " and what are accustom to listen for many years and what you like. I understand that perfectly and I'm not against you or tubes in any way, that is not my attitude here or every where with any of my posts in this or other audio regards.

Why understand I what you like r accustom to? because I use to have tubes for many years in my system and almost owned or listened all kind of tube electronics from  the humble ones to the Ongaku by AN or top Lamm or any you can name it.

Yes, I was accustom to the tube colorations and I like it.

One day I ask me:  what if what I'm listening is wrong? and started to increment my listening sessions ( attend more often. ) and then I confirmed I was wrong and decided to return to SS technology and I did it. Since then day by day experiences just confirm that that was a good no-return choice.

Btw, I'm talking of home audio systems. I don't care about electric guitars, microphones and the like, for all these we can have a serious dialogue in a dedicated thread not here. Repeat: home audio systems as all we have.


""" designers of SS things (which, of course, often sound fabulous) mention their "tube like" sound  ... """

Yes, that's true and there are some reasons about why is that and one of those reasons is the obvious:

90% of the " high end " audiophile systems are surrounded for tubes and it's almost impossible to " figth " with true justice against that " fact ".

That's why some SS designers changed their usual designs that were normally using bipolars devices for FETs/MOSFETs that sounds more like " tubes " but this does not means in anyway that those SS designs are " like tubes ", way different.

How many time took me to be sure that SS was and is the rigth and only valid alternative?, around 3-4 months to in deep system and live MUSIC sessions were I listened only SS electronics where I never " touched " the tube experience.

After that true SS experiences I changed in my system the SS for tubes and was pity for say the least. I never returned to that poorly experience.

That's the way I learned about the true SS alternative and was ( in different times. ) the same way how I learned that the DIGITAL alternative beats the ANALOG one.

When I did it and had all those SS/Digital experiences I decided to do it erasing what I like it: tube colorations/distortions or LP colorations/distortions. I took the challenge challenging me and what I learned through the corrupted AHEE where I belong as any one else.

Is important to say that I'm not " married " with any kind of audio items or technology I'm married only with MUSIC and my main audiophile target is to be truer/nearest to the recording and to achieve that critical target I need that the home audio system stay with any kind of system/room distortions at minimum, nothing less.
What I like it or what all of you like it is jus unimportant, I'm not talking of that I'm talking on how MUSIC sounds and should sounds through a home audio system.

Our/my self design Phonolinepreamp Essential 3160 has almost no signature: no SS and certainly not as tubes. NEUTRAL could be the rigth word. Like it or not that unit is not important. 



""" The anti tube strikes again ! """


this post is really gentless compared as the ones I had when I was " striking ",  different times, with other main audio subjects like these:

- Was I wrong when I brougth here the TT DD alternative in a BD audio world?: time confirms I was not wrong, even from some years now many gentlemans makes money thank's to my " strikes " on DD subject.

- Was I wrong when I brougth here the pivoted tonearms with interchangeable universal headshells against a fixed ones analog world?. Time confirm that I was not wrong.

- Was I wrong when I brougth here the MM alternative in a LOMC cartridge audio world?, time confirmed that I was not wrong.

- Was I wrong when I brougth here the system subwoofers subject?, time confirms that I was not wrong.

-Was I wrong when I brougth here the different geometry tonearm/cartridge set up alternatives?, of course not.


and I can go on and on. In all those examples people ( almost all. ) laughing ( literally ) of me and they did it because as you ( on tube subject. ) just do not learned about.
I posted here on all those audio susbjects when almost no one " touched " but in those times not even the professional reviewers did it.


First premise to learn is to have a positive not biased attitude that with out it you just can't learn and just can't grow up and have fun with MUSIC and not with hardware.


Regards and enjoy the MUSIC not DISTORTIONS,
R

I get paid (some may say "overpaid") to mix live concerts so I know what music sounds like, until I ruin it with my mixes…anyway, regardless of the opinions of any anti tube crusader, tube are more fun. They just are. By the way, being anti tube can't be easy these days…most great amp designers of SS things (which, of course, often sound fabulous) mention their "tube like" sound which must make anti tubers cringe. I just worked with a serious tube abuser guitar player at a show…this guy runs his Princeton Reverb on 10 and gigs often so tubes die regularly, as well they should in service to the Mojo.

Tubes do nothing but degrade the sound huh?  Let's get rid of all tube microphone preamps and tube guitar amps and see how enjoyable the music gets then.

rauliruegas

That¿’s the only fun tubes can gives to audiophiles: rolling tubes.

I don’t think playing with tubes is sun at all. It’s just goes with the territory.

That totally anacronic technology can’t really honor MUSIC in anyway.

Sez you. Are you aware that some of the most extraordinary recordings ever released were made with all-tube electronics? By the way, Raul, use of ALL CAPS is considered shouting.

Thanks Raul for the heads-up, I always figured that there was something missing that I couldn’t quite put my finger on, you have illuminated it so well in what it takes to realize music in a complete FULL sense outside of the live experience, just the music,I hear you, thanks again for that epiphany. But then again there are many things, old-fashioned, that fit like a glove, wouldn’t you agree? Kind of like comfort food :)

The anti tube strikes again !

Dear @jbhiller: That¿’s the only fun tubes can gives to audiophiles: rolling tubes.

That totally anacronic technology can’t really honor MUSIC in anyway. Now, if you instead to follow having fun rolling tubes what you want is to have real fun enjoying MUSIC through a home audio system, that’s the target of any serious audiophile or should be, then you need to change to the only alternative that can do it: SS, I’m talking of MUSIC not just sounds as you have rigth now.

Yes, as with digital with the SS alternative you can't roll nothing because you need nothing to rool other than enjoy CD LP and be truer to the recording.

After all our LPs we have it to a truer enjoyment of MUSIC and only SS can do it. With SS we only have to worry to buy new software ( LPs or CDs. ) to follow enjoying MUSIC, just MUSIC that comes in the recording.

Of course is your very personal choice and your privilege, no one else.

Regards and enjoy the MUSIC not DISTORTIONS,
R.

I too have had excellent results with the Gold Lion reissue 12AX7 and 12AU7.  This was in a Chinese-made EL34-based Paxthon VTA-160 amplifier I used several years ago.

Regards,
-- Al
 

I found that Gold Lion 12AX7s are great, as are reissued Mullards. I use NOS 12AT7 type (6201 or something) Mullards also since there seem to be lots of them, but the Lions sound fine and as long as Russia allows them to exist I'm happy with that stuff. Russian GL KT88s are superb.

The new production Mullard and Tungsol 12ax7 tubes are nice, I can live with them no problem.  I suppose the 12au7 versions are fine too but I have not used those.  I don't care for new 6sn7.  I have a stash of GE, CBS, Hytron, RCA, Raytheon, Sylvania, Kenrad, Soviet ones and a few others. They should last a lifetime but if some anti-ageing procedure is invented and I manage to outlast them, I would get the Shuguangs.  Oh and you have to try JJ  6ca7 tubes, they are one of my favorites.  Big ballsy sound!

The very best 12AU7s I have heard in my system were supposedly selected 12AU7s that were made in China.  I bought them from Billington in England, and they were "Billington Gold" class.  The only drawback was a relatively short lifespan compared to any of the other 12AU7s I tried, all of which were NOS.  The best NOS by far were Amperex BugleBoys, real ones, not fake ones.  I bought them in the 70s, so I know they are the real thing.  (No one had started faking NOS tubes back then.)  Once I realized that 12AU7s per se are not the best sounding tube, I stopped caring about which brand sounds better and converted all my gear either to use 6SN7s or 6CG7/6FQ7s.  Those two have nearly identical characteristics to a 12AU7 and can be used in any circuit that uses 12AU7s, to great advantage.  But you have to do some re-wiring, in both cases. Well worth the effort.

I agree with lowrider, 6SN7s are hellishly microphonic.  Best I've tried are either KenRad 6SN7GT with or without the silvery glass coating or RCA 6SN7GT with the gray glass coating.  But you've gotta damp them somehow.  Wonderful tubes, nevertheless.  Another one to think about are 12SX7s, which require 12V filament supply and have the characteristics of a GT type (as opposed to GTA or GTB types, which can take a higher plate voltage). 12SN7s may be a bargain, too.

Are there any decent Russian small signal tubes that have the characteristics of NOS? Many 6SN7 type NOS become microphonic and are very noticable in preamps.

I have abandoned NOS in favor of Psvane Premium tubes or Shuguang 50 year Treasures if available in the specific tube sought and have been really happy.

The Gold Lion KT 77's sound great in my ZOTL40, only NOS Mullard EL34 are better.