NOS Tubes - Ecstasy or Agony

I have been running tube amps for many years and have built a number of SETs and other tube amps, kit's mostly.  My main power tubes have been 2A3's and 300bs and I have used mostly new manufacture tubes including JJ's and EML 300b's (great tube btw).  I did use NOS driver tubes and headphone amp tubes.  Never really had a problem.

I just transitioned to a Don Sach's 6sn7 based preamp and McCormack SS power amp.  The preamp is very nice and sounds great with Shugang tubes. Of course, I wanted to try some NOS tubes, went online and did my research.  Now the DS2 is a great preamp, the drawback is it uses 4 6sn7s and so I need to get pairs.  Would  have love to get my hands on the Dehavilland, uses one tube!

First Pair - I ordered some Sylvania's from TC Tubes. Advertised as 50's vintage, ,when I received  them they were marked 60's. Hmmm.  So I tried them and they sounded pretty darn good except after a couple hours one of them developed a high pitched hum, like a florescent bulb. So I sent them back.  

Second Pair - ordered from Brent Jesse - has a good rep online and a really informative website.  Received them and one was dead on arrival, they were also clearly of different construction. So they are going back.

Next will try Andy at Vintage Tubes Services, he also has a solid  reputation so hopefully I can get something that works.

I am curious what experiences others have had. Maybe its COVID, or are these dealers just unreliable, or is just 6sn7's?  Really thought I could just buy some NOS tubes and experiment, I can't even get two to work.

I don't really want to disparage these dealers but I do think all the claims of testing are maybe overblown.
I rarely have issues with my NOS tube orders, especially 6SN7s. I recently ordered some Tung-Sol mouse-ears (highly recommended) from Brent Jesse and they perform well. I wasn’t thrilled with the cleanliness of the tubes though.

Andy of VTS overpacks them for shipping and of the many pairs I’ve ordered from him, all have been reliable. He also polishes the pins, other sellers do not IME. Andy has a penchant for recommending RCAs and each time I’ve been disappointed with their tonal balance. If you buy through him, I suggest skipping the RCAs and going for Tung-Sols or just about any other make you can afford. He basically prices them by their sound quality and detail IME. I’d pretty well ignore what he says about tonal balance. 

I’ve also had great experiences with Bullz Tubes on Ebay. 

For whatever it is worth, I've bought most of my NOS tubes 6SN7s , 12AU7s , 6922s and other preamp tubes, as well as ,rectifiers from Brent Jessee with no issues and full reliability. Bought some NOS rectifiers from TC Tubes no issues, and occasionally some NOS preamp tubes from Tube Depot, reliability wasn't an issue with them as well
Brent is standing behind is product. i spoke with him and we are replacing the tubes with some VT231's.  Hopefully these will work out.

Helomechi - I did order some RCA's from Andy. He does seem to think they are the best sounding.  I need two pair for my DS-2 so I can always use them in the buffer position if they are not as nice as the Sylvania's.  I guess I should bite the bullet and try the Tung Sol's . . .  suppose I am already down the rabbit hole.
Interesting thread. I am in the middle of listening to a number of different NOS and not NOS tubes in my preamp. They range from Telefunken to Valvo's to Siemens to Amperex to Brimar's, etc. 
The question I always wonder is what does NOS mean to me New ( and there's the key word!) Old Stock (NOS) should be a BRAND new tube that has been in stock, unused, until purchased by you...the consumer. Unfortunately, this nomenclature doesn't apply to almost all of the tube their new( sic) is everybody else's either a) gently used, b) heavily used or c) maybe used..maybe new! 
To that, we see discrepancy in how tubes are tested and what a passing grade is for the tube...some of these very same folk believe that 80% of new is new...some believe that so long as the tube has ok microphony, gain balance and no gas issues--it is new! 
Then we have the protocol of how the tube is tested( or not) and what tube testing gear is being used...and lastly what is the expertise of the tube tester in his ability to read/understand and utilize the tester. ( When was the tester last calibrated etc.,). Many questions and not too many answers. OTOH, I am always pleasantly surprised that these NOS tubes really give one a very nice boost in SQ over the current production tubes that are available. ( At a cost in $$).

To add to my post...
I do suggest that taking advice from tube re-sellers as to what is best sounding is probably not the best idea. Many of these folk have some experience ( if we are being kind here) with listening to a tube in their own gear, which in some cases (most?) will either be a) less resolved than yours, b) as resolved as yours...but totally different in regards to the set up and c) not your level of expectation when it comes to tone and timbre. While I do believe that a general idea as to what the tube in question sounds like...whether it is a little bright, unable to really dig deep in the bass etc., is accurate, the true SQ from any tube is going to be up to the end user and his particular gear and taste/expectation.
Only way to know is to place the tube in your gear and listen.
As to issues with noise and other drewh1 found out, best to deal with a reputable dealer/re-seller...and pay their up-charge.
Never have had a problem with Brent Jessee.    Recently (5/2020): bought his last pair of NOS, T/S Round Plates (40's/6SN7GT/spring top support) and couldn't be happier.      Far as TC Tubes: My last octet of GE 6550's (from them) had one that went South (wouldn't hold bias), after about a year of use.      I sent them all in, to be tested and they found the rebel.      They matched one up (brand new, but- measured low) to the remaining seven and gave it to me, mentioning that they couldn't have sold it as first-quality/NOS, anyway.      I wasn't expected that kind of service (a pleasant surprise).    
Hats off to the Marketing genius who came up with the term "New Old Stock".  Well done!
mapman"Hats off to the Marketing genius who came up with the term "New Old Stock". Well done!"
Why do you say that it makes sense to me as a way to distinguish, separate, and characterize current production tubes/valves from those that are from old production and often from factories that are no longer even in business.
Because they are all old, not new at all. Granted some are still in like new condition, maybe never used, hopefully at least tested.

They don’t call a used car in good condition NOS. IT’s just used....and sometimes also very old.

Marketing genius. Just be careful....
Great feedback on these vendors. Thanks all.  It seems with "NOS" tubes buying from a seller that backs up the sale is worth a couple extra bucks. 

FYI - regarding the 6sn7 here is a page on the Dehavilland website that I found interesting:  

mapman"they are all old, not new at all. Granted some are still in like new condition, maybe never used, hopefully at least tested."
The tube is either new or it is not. A tube can be old but if it has never been used at all then it is properly and correctly called "NOS" but if it has been used then it is not new and it can not be designated "NOS"
How do you or even a seller know a tube labeled NOS has never been used? No telling where they have been. Literally. They are old so they’ve been around...

It’s still old even if never used. Old tubes today may not last as long as when they were new.

Whatever. It’s all is what it is. Bravo to the Marketing Guys who came up with the name NOS.

If NOS is what you want, just buy from a reputable source who offers some kind of warranty or guarantee and all is well that ends well. I would not trust that every tube called NOS by any Joe blow out there in fact has never been used or will even last very long. Old is old. Someone reliable needs to certify and back that up. So just be careful, that’s all. Always good advice when dropping $$$s for something especially at a premium price.

Personally, I would avoid new products that require old devices to sound their best, but that’s just me.
I find it amazing how good some of these NOS tubes sound from the 40’s, 50’s and 60’s. There has been many a tube I have purchased that the outside boxes are disintegrating as well as the inner wrappers and you need to clean them up with alcohol because they are filthy but you plug them in and they not only work but some of them are just flat out beautiful sounding. I don’t know too many things that can be stored for 50,60 or 70 years and work just as well as the day they were made.
Mapman - I don't think it is about devices that "require" old devices to sound their best. Mostly there are pretty good modern tubes out there. I think EML makes tubes that rival the supposed NOS stuff. However, there are some really good old stock tubes that provide a sought after sound. To some degree they all act as tone controls varying slightly the tonal balance of the equipment.  

I do agree, I wouldn't want to have to rely on them though.
NOS is brand new untouched sealed in the box.
I would prefer the term old stock but tested.
After all only a tested tube, new or used, is required to match our needs.


Some NOS tubes I have seen have clearly been used in some kind of electronics for decades. If you look at the tube pins, they are not only corroded, but also generally not that straight! The only 'New' thing about them will be the new owner who acquires them in the sale! Luckily, it seems that a lot of the better 'NOS' euro tube manufacturer's made tubes with enough quality to last for multiple insertions and hours....Too bad this doesn't seem to be the case with today's manufacturer's. 
Bought numerous "NOS" tubes, mostly through Ebay. Some from the Tube Store, and some from upscale audio. All of them have been as described. Some from Ebay I already knew were not brand new, as the seller disclosed this, despite being listed as NOS. I am loving my combo of GE 12au7, RCA 7025, and my Sylvania 5751 with disc getter. Sounds wonderful through my Tavish Design the classic.
NOS is not only a marketing ploy. Tubes do have an end life to them. I would expect when I buy a “new old tube” that I can expect 100% of its life expectancy. Not 80 not 50 but 100. There is no test that can tell me this. I can run a tube for 3 years and it will test the same as one never used. I have made pease with the fact there is always some luck of the draw with anything electronic and the evil gremlins that can be there. Electricity is kinda like Mother Nature. They are and always be undefeated all I want is for them to be on my side.
6SN7 tubes my pre take 4. I run sylvania 1950 bad boys in my gain and brand new tungsols in the buffer. Sound is detailed wide and 3-d. My dream would by finding the holy grail of telafunkins but can’t justify paying more for a tube than I did for my preamplifier. Have used T/C tubes and have no complaints.
I see any tube as a gamble to a certain extent. Much like all the rest, just somewhat higher risk I would say.

If you must drop a lot of $$$s on tubes, buy only from reputable sources with a rep for good customer service. Or else go cheaper when possible and risks not so great.

In recent years I’ve only bought tubes from two sources: 1) Audio Research or 2) Guitar Center to play with cheaper options where practical. Sometimes it is practical, sometimes not. For example, tubes used in a phono section probably need to meet higher tolerance standards than those in the line stage. In my Audio Research sp16, 1 of three phono section tubes must meet higher tolerance. Only pricey tube from ARC will do for no audible background noise. All others (5), not nearly so much.  If you buy all six,  that one costs more and is marked for use in the proper place.

I do not do tube power amps to-date so no recent experience there.
In the past, I have had great success with NOS tubes. But recently, have had consistent failures of 12AT7s. Bought 3 pair from,I thought a reliable source.
Have made a note of Brant Jesse. I have been told that NOS, especially for a preamp, are rarely quiet enough. Normal testing only reveals the main functions of a tube and not how it will sound. Believe a complete test must include actually putting the tube in a component. And hearing it for several minutes. I doubt that many or any tube sellers will do this.
Manufacturers may do this for their stock tubes. But, I think, most will use cheap new stock tubes that they buy by the hundreds in order to find the good ones. Am getting a new preamp with 18 tubes: 8 12AT7s and 10 6SN7s! They will all be new, all Chinese I think, tubes that were sorted out and “completely” tested.
Maybe Brent can supply tubes sorted. I am very hesitant to replace the stock tubes. Psvane offers some tubes that have been sorted out from many. Don’t know if they do a complete test but they do charge a lot for these “premium” tubes.
Brent and Andy both grade tubes based on microphonics for line stage use vs phono.  

And I want to say, Brent has been outstanding on follow up and helping me get a good set of 6sn7s for my DS-2.  I feel the extra effort is worth it. I have a nice Pass Labs passive pre, love it, but it doesn't compete for musicality with my tube pre.
Two of the most satisfying changes to my system are attributable to NOS tubes.   The first was a NOS Mullard in the power supply of a Modwright 36.5 linestage. My jaw dropped.  The second was trying NOS Sylvania and Ken Rad 6Sn7's in a VAC 200 IQ power amp.  The Sylvania were amazingly transparent. The Ken Rad's were full bodied, clear, wide bandwidth and my final choice.

What I like about this is that dramatic changes are available for a few hundred dollars, you can deep dive into researching the subject, you can gain access to some of the best ever made, and what you get probably won't depreciate. It lets you be a hands-on hobbyist again as audio increasingly moves to streaming (for good reasons) with locked-box appliances.  Yeah, there's some current obsession with getting digital data to the DAC, but whether real or imagined, that's complete solvable beyond further improvement, but I digress. 

Shout out to Brent, Vintage Tube, and catluck.

I have purchased several singles and matched pairs of NOS from Upscale Audio. All have been just as advertised and no DOA's. I personally don't believe there are many, if any suppliers who do the kind of comprehensive testing that Upscale does on the tubes they sell. And no, I am not a paid spokesperson, just a very satisfied customer.
NOS...."New Old Stock", only 3 weeks old since demand has fallen off of late....

"Hey, Lorraine? These boxes aren’t ’aged’ enough to be ’believable’. Can you smudge them up a bit more?"

Does anyone truly believe there are stashes of old tubes out there Still?

If so....I've got some lake bottom property next to the Brooklyn Bridge to put up an 'old condo' on.....
All you have to do is a little searching. Here is a recent auction on ebay. Scroll down so you can see the actual sale of 10,000 to 12,000 tubes.
I think NOS tubes are an area where who you're dealing with matters more than anything.  

My experience has been that tubes matter a lot more in a preamp than an amp.  I've had tubes fail in my amps, but I've never experienced a sound quality issue related to a tube in any of my amps.

On the other hand, my Modwright LS100 which also uses 6SN7 tubes will not only reveal the characteristics of the sound quality of any given tube, but also noise and/or microphonics.  I would say that probably 30% of the tubes I've purchased, including some highly touted new ones, have been microphonic or became microphonic after a short period of time or had unacceptable noise issues.

Which goes back to my initial point.  Brent Jessee has been my go-to guy.  For a few bucks extra he will guarantee his tubes (for 2 years I think?).  Whenever I've experienced an issue, he's been great about getting me a replacement, or if he doesn't have one, recommending something different.  I've also had good experiences with the ebay sellers I've bought from, but I make sure that they have 100% feedback and a lot of it. 

I had some issues with a pair of tubes recently and the seller tried a few in his preamp and sent me four to try and told me to keep the two that worked best.  I've had other good experiences with ebay sellers helping me make sure I got a good tube(s) that would work well in my preamp.

As far as buying a pair of NOS tubes that don't exactly match as far as their markings, that is not unusual, at least in my experience, nor does it concern me.  The same tube may have been sold under different brand names.  As long as the tubes themselves are the same and tested and matched, it makes no difference to me. 
I buy my tubes through

NOS and NNS (new new stock) @mapman I am a marketing genius.

Never an issue quality tubes and alway have what I am looking for.

Excellent service and fast shipping. 
Quick update - finally got the tubes from Brent. Latest issue was the package got lost in the big storm so it took them weeks to get here. RCA VT-231s.  Very sweet sound, with a nice balance of bass and sparkle. Definitely more depth and air then the Shuguang's  They have a little hiss but I will give me some time to burn in per Brent's advice.  Definitely takes my system up a level.  I have a pair of Ken Rad's coming so I am interested in hearing those as well.  
If they’re the staggered plate, copper post, bottom gettered K-Rs; they’ll be a tad less warm than the RCAs, with nice sound stage/detail recovery (a quiet tube).        Solid/clean extension on both ends of the spectrum.    Have fun!
I am so glad to have sold some years ago my headphone tube amplifier...With 50 tubes....A basrgain for the man who bought it.... 😊

I had no problem with the tubes tough...Nor with the amp....But i trashed my 7 headphones in a drawer.... My audio regular system work now optimally and beat them all on all count....

I dream now of a tube amplifier where tubes dont make heat at all and enjoy an indefinite life....Nothing else...I dont want to change tubes and gauge them for longevity and steady working...I hate heat in summer....I dream of an ecstay without agony....

I will bought it if i had money on the spot if this kind of tube amplifier exist...

But yes it exist: Berning ZOTL amplifier...

I will never upgrade my Sansui AU 7700, it satisfy me on all count tough.... A low cost dream comes true....

My only other dreamed amplifier is this Zotl one, not for an upgrade, i dont need it, but because it is a revolutionary new tech with tubes and probably an upgrade anyway....

I am going to wait for Santa Claus to listen to my wishes before the world end or before my death.....


NOS Tubes - Ecstasy or Agony
Yes :)
@drewh1  We use a lot of 6SN7s in our circuits both in preamps and amps. The Shugang tube is a copy of the Phillips JAN tube made in the late 1970s and early 80s and sounds almost the same. The Shugang factory burned down in August of 2019 so these tubes are becoming scarce. I understand they will be setting up production again though.

The JJ tube is pretty decent FWIW.

If you like to play with older tube types a tester is a good idea, even if the tubes are coming from a good source like Andy at VTS.

Our customers have commented that the Psvane 6SN7s have all the best qualities of the NOS tubes without the weaknesses. That's a pretty serious statement! I've heard the same thing about the Sophia tubes, but at least in our gear, we've only seen them run about 6 months and our gear isn't that hard on 6SN7s- we've seen the Chinese tubes go for years.

The 1960s Russian 6SN7s are quite good. The later Sovtek tube looks very similar but is arguably one of the worst 6SN7s IMO. Its rare to see the newer Russian made 6SN7s not show some leakage on the tube tester.

So far the best comments we've heard from our customers on NOS 6SN7s have been about the Sylvania metal base Chrome Dome (which dates from WW2), the KenRad and the RCA redbase (which is nearly the same as the CBS Zalytron).

Please consider posting your observations on the thread below. It was intended to be a more up to date repository of exactly this kind of information, since so many of the reference threads that pop up in a search are years old...
I feel as though there are very few hard and fast rules when it comes to tubes.  I think it is always a gamble and there are ways to reduce your risk of a not so great outcome. 

I've experienced: 

  • Used preamp tubes lasting forever with no noise or microphonic.  
  • Used preamp tubes lasting 500 - 1000 and fading out fast.
  • New preamp tubes outperforming some great NOS offerings, even those sold by great dealers with great reputations for quality. 
  • Inexpensive reissue preamp tubes performing much quieter than expensive NOS.  Laugh if you want, but Electro Harmonix 6922s, 12AT7s and others are very quiet and lovely sounding.  
  • Used preamp tubes sounding like heaven in a vacuum. 
  • New reissue preamp tubes falling down at 1000-2000 hours.  Unacceptable, but common. 
  • New power or preamp tubes actually sounding their best earliest in their life--despite all of the notions that hundreds of hours of break in make things sound better. 
  • A reissue or NOS sounding not so great in one circuit but ok or great in another. 

The comments above about not knowing how long any given tube will last are spot on.  We never know. 
Thanks for your comments Atmasphere! your products look awesome.

RCA's had a nice sound but were terribly microphonic. So they are going back.  I am having such bad luck, I wonder if something about the circuit in my preamp is especially sensitive to microphonic tubes.

Now awaiting the Ken Rad's from Andy. If I get some decent tubes from him, i'll buy another pair of the RCAs to try as I really did like everything about them (except the noise).
I wonder if something about the circuit in my preamp is especially sensitive to microphonic tubes.
It probably is. If that is the case, you have to handpick the tubes for low microphonics. Its a good idea to specify that to the supplier; if they can't do it than you'll have to- by buying tubes, trying them out and sending them back if the microphonics are unacceptable. Keep in mind that all tubes have microphonics so its not a matter of getting rid of them as it is getting them low enough that they are not noticed. If operating the front panel controls of a preamp can be heard then I would consider that unacceptable.
I no longer  think there is an issue with the preamp. I started a new thread but wanted to reply. here to atmasphere.

I just recieved a pair of '56 RCAs and '53 Sylvania's.  None of the tubes are microphonic. even quieter than the new Shuquangs.
If you buy from a reputable and experienced seller, true NOS isnt so difficult to spot. Test results do not indicate NOS and it is not uncommon to see used tubes test near or even above typical NOS levels. Not heard to comprehend when you see variations from new factory tube of up 25%. Same type, same manufacturer and even similar production dates. Beware "NOS in white boxes". Just because a tube tests as new doesnt make this tube NOS. A very good indicator, perhaps the best, is to check the tube pins out under a loupe if one thinks the tube may be NOS. 
Another thing, there are no 2 hole plate Sylvania Bad Boys. A true Bad Boy has 3 hole plates with a bottom getter with dates ranging from 1951 to 1954 (base may have been printed at a later date). They are unique and they sound different.
I have one Sylvania (40's/bottom-getter/two hole*) VT-231 and a T/S Round Plate (metal top support), in each of my Cary monoblocks.   In the past 20 years of owning the amps, no combination has taken me, "there" better, regardless of ancillaries.                                                                *identical to these:    That seller is REALLY proud of his pair!
I only buy my NOS tubes from Andy Bowman at Vintage Tube Services.  He is the only one I trust and his has kept his prices in line down.  Others have raised their prices.
I've had very few tubes fail over the years, and 2 were new (a Sovtek KT88 and a new Gold Lion rectifier)...the other was a JAN Phillips 12AT7 that was replaced by thetubestore. All my piles of NOS GEs, Sylvania "Chrome Domes," etc., have performed perfectly...including those abused in tube guitar amps as well as hifi gear. I'd say tubes generally have been pretty damn reliable over the last 50 years or so I've been using 'em.
Goose - please stop recommending Andy, he is a month behind on orders and I want to get my tubes before anyone else orders! :)

Actually, I spoke to him today and he is holding off on new orders until he gets caught up. 

Old thread, but I found it because it’s something I’m thinking about right now. After 30 or more years of doing nothing but all tubes, and primarily “NOS” small signal tubes (never bothered with “NOS” power tubes), I stopped completely about 5 years ago, sold my tube preamp, tube cd player and mono tube amps and went to a naim cd player and a Plinius solid state integrated amp. I’ve never been happier. BUT, recently, having become obsessed with headphones, I bought myself a McIntosh tube headphone amp and, of course, started to think about tube rolling. As another poster said above, over the years I have had new tubes that didn’t sound good or didn’t last, old tubes that didn’t sound good or didn’t last, new tubes that were reliable and sounded good, old tubes that were reliable, some of which sounded great. I can say that newer production tubes are usually the most reliable, even if they’re not sprinkled with 1960’s era fairy dust and don’t give you that special something you can sometimes get with old tubes*

Anyway, as soon as I started rolling in old tubes, I immediately also began worrying about and listening for whether or not the tubes were sounding tired, rather than listening to and enjoying my music. This heightened anxiety over the state of the tubes detracting from my enjoyment of music is one of the reasons I gave up on tubes 5 years ago (Post Tube Stress Disorder?) - to me, it’s not worth it. There are plenty of good current production tubes available, and that is what most manufacturers (other than a few ‘boutiques’) are using to voice their equipment. Of course, with the current political climate, Russian tubes are suddenly become scarce, so even good old reliable (and, IMHO, very nice sounding) eh tubes are starting to command higher prices. Better stock up now so that in 2033, you can auction off your NOS electro-harmonix gold pin 12at7’s for $200/ea.! In all seriousness, having put myself through the mill the last few weeks - cv4024, 6201, RFT, GE, RCA, etc., etc.), I’ve put back the oem McIntosh branded (they won’t say, but pretty sure they’re JJ) tubes, and that’s where I’m going to stay for a while. I might order a set of eh gold pins as a back up, but I do not think that I can bear the constant agony of dealing with so-called ‘NOS’ tubes in the hopes of finding that magic combo which, for 10 minutes or so, might provide musical ecstasy, before I remember that they’re 40, 50 or 60 years old and I start listening for signs of fatigue. 

YMMV, IMHO, just my $.03, etc., ad nauseum.

*NOS should mean NEW old stock, but it appears that the term is now used for any tube made before ~1990, whether or not it is actually new (as in unused). Reputable dealers who aren’t certain will often state that the tubes ‘test’ NOS, rather than declaring them actual NOS, but it seems to me that for the most part the term has taken on a secondary, incorrect meaning for use in describing any tube that isn’t new production, regardless of its actual provenance. 

The longest lasting NOS tubes I have ever purchased came from Andy. It's worth the wait.

     UPDATE (just a little fyi):  STILL have the same Sylvania (40's/bottom-getter/two hole*) VT-231 and a T/S Round Plate (metal top support), in each of my Cary monoblocks (per my 3-21-2021 post) and they are STILL performing splendidly, far as taking me from, "here" (my listening room) to, "there" (the recording venue). 

     There are a multitude of variables*, when it comes to purchasing vacuum tubes, whether NOS or new production.       PERHAPS, the most important: your individual knowledge/research on the subject.

     It's been my experience: the aural benefits/attributes of listening through a tubed system I value most, are (invariably) best generated by components equipped with NOS valves.

Both agony and ecstasy, as many of you are aware.

Vintage 6SN7 are quite often problematic in preamps (except as follower outputs), due to noise and microphony. 6SN7 are usually totally awesome in power amps (as phase splitter / V1 or driver tubes). The later GTA and GTB variants tend to be much quieter (OK for use in preamps), but have less sweetness to their sound - they do make great KT tube drivers in amps, though. 

I've bought lots of tubes from Brent Jesse and Upscale over the years, both great 99% of the time. They're human, so mistakes do get made (I've had a mistake from each) but these cases are the outliers; both sellers are honest so they'll work to rectify any issue. 

I've also got tubes from Andy / VTS, and they are as advertised; the problem is a lot of his stock is RCA and (in the end) those tubes have never worked out for me sonically. For the better part of a year I had some VTS low-noise selected RCA 12AX7 in my VAC Renaissance SE phono stage, never initially questioning them (dumb). They were indeed very low noise, matched and strong. But the sweetness and warmth of my VAC was all gone. I started to blame the VAC! When I finally got back to rolling in other 12AX7 makes, it was immediately apparent the RCAs were 100% at fault - bright and lean sound, ugh. Thinking back now, I just don't like RCA - sure there are exceptions, but even with those, there's always a different make I like better.

Ebay is a crap shoot, as expected. I've gotten good and bad tubes there, in equal measure. 

The modern Russian tubes are fantastic; the sub-brands each have their own sonic flavor, and they're easy to find in low noise matched pairs. BUT they still don't have the 3D holographic image or ultimate articulation and refinement of the very best vintage tubes. Their warmth seems a bit more 2D and less nuanced, somehow. 

RCA's can sound great. I rolled in a pair of Clear top 12AU7's into my amp and the soundstage increased considerably. One thing I have found is that IF one can source an organ re-brand, which these tubes are ( Hammond) then they are a little less noisy than the original labels. Not always, but mostly.

@daveyf Agreed on the organ pulled tubes. The RCAs black plates and other classic American 12AU7( AX7?) from organs I’ve used have been uber quiet and sounded excellent, but I no longer use them due to system changes (my RP9 preamp uses 6H30s). A plus is that the organ pulls are cheaper than "NOS" and they have been essentially pre screened for low noise and performance. The RCA black plate organ pulls I’ve used are superb as gain and driver tubes.  Also, I can't type "organ pulls" without giggling, sorry.