Simple and short answer...The demand for vacuum tubes is not great enough for a manufacturer to lay out big bucks for production.Just my opinion,others will disagree and that's fine.
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I have always thought it was quality control. I know that Chinese tubes are sorted by quality and sold at different prices. I suspect that many tubes in an earlier era were merely discarded. I remember radio stations buying tubes in big boxes and plugging them in side by side. Those that didn't glow were quickly discarded.
I also expect that the women who made them became quite skilled and consistent. I doubt if that level of skill is available today.
One thing is for certain the old NOS tubes of even the 1970s are become rare as hen's teeth.
There was a link on the new Mullard site worth checking out. It showed the process of making tubes in the 50/60's. Watch that and you will understand why a) they don't make them like they used to and b) why there was a big push to go to transistors. The amount of machinery, the precision necessary at every step, and the error/failure rate even at the Mullard factory are fasinating. That said, some of the new manufactured tubes are pretty good and seem to be getting better.
It would seem by trial & error over the years that there should be no problem manufacturing a superior tube. Even the machinery involved in producing tubes could be compacted, streamlined, and improved given this computer age. It may simply come down to supply & demand, maybe not enough orders to justify the factory investment. Audiophiles represent a small segment of society, thus the demand is not that significant since a tube's primary application is an audio circuit.
Quite simply because life and death no longer depend on the quality of a vacuum tube, the way it did back in the hay days, during WW II, when tube technology drove design and manufacturing to the maxx.
We now just use tubes for a casual hobby, lives are no longer at stake, so there is a HUGE loss of military funding for vacuum tube design and manufacturing quality standards.
As Jmcgrogan2 mentioned, when military electronics, including radios, guidance systems and computers, were run on tubes, their reliability and endurance was paramount. Therefore, the tolerances, consistency and reliability of the tubes than ran the equipment were driven to the extreme. Hence, vintage tubes of the 40s, 50s, 60s and even 70s (particularly Eastern Bloc) were of excellent quality that cannot be matched today simply because modern military electronics don't require it, and therefore there's no large scale market to drive tube quality.
I heard that RCA used the same machine to make tubes for 50+ years and every year the fittings got looser and looser so the newer tubes lost a bit of quality each year compared to the original tubes. I forget any more specifics but the general idea makes sense to me (in this instance). This is one part of the equation it seems...
Tubes these days are fired incorrectly so there are contaminants caused by the getter being under or over-fired.
Cathode structures are not being built with proper care. Contaminates get introduced, causing grid contamination during the operation of the tube and also causing arcing as the cathode coating flakes off the cathode.
There is a new US manufacturer of tubes in Carson City, NV that was showing at THE Show just last month. They are starting with a new 6L6 and expect to have a KT88, 2A3, 300b, 6SN7, 12A-series. They seem to be well funded. RCH Labs. The 6L6s they had on display looked quite nice :)
I wonder which the world will run out of sooner, good high quality NOS tubes that are years old or oil?
I hope the suppliers of modern tube technology get their act together sooner and better than those making the new vinyl seem to be doing.
I have to believe though that the ability to make good tubes cost effectively still exists, even if it might not occur that often in practice.
I have no clue really. Too few data points with the tubes I have used personally in recent years. Overall, they seem to do the job well, though getting very quiet ones suitable for use in a phono pre-amp seems to cost a premium.
Definitely a good idea to buy from a reputable source that has the ability to accurately measure and rate each tube. I would expect that at a minimum in general, unless attempting to buy on the cheap, which will surely be more hit or miss in general.
Hi Atmasphere, I am very interested with your finding of this new tube company in carson city, NV,, I believe if they have less dies, the tube will be made to last longer, and maybe be as good as ww 2 nos tubes, you said they were going to make the 12A-series tubes, I would be grateful if you could E-mail me information on them with pricing, if they have prices yet?, you can E-mail me thru audiogon here, thankyou Ralph.
Me too Atmasphere. While I find the sound of the newer tubes in some cases to EXCEED any of the NOS tubes I've tried they just don't hold up for whatever the reason(s). I would LOVE to purchase tubes that are made in the US and would hope they exceed the performance of the NOS but retain the quality and longetivity that the Chinese tubes in particular are seemingly lacking.
This thread is astonishing. Many new tubes are fabulous (KT120s have been nearly unanimously accepted as great), guitar amps use FAR more of the available tubes than home audio geeks ever will, and new "boutique" tube amps and reissued amps sound mostly better than ever (and 99% of 'em are sold with new tubes). Tubes like the high end Psvanes are beautiful, very well made, and sound amazing. I've only had a few tubes not do the job or fail in my many years of using 'em, and among those were NOS tubes. So, basically, you're all insane.
I hope Atmasphere is right. The man over a Vintage Tube Services in Mich. told me it is an human craft. Like Ebm says. You da man Ebm. Anyway he told me the extent they went to to produce good ones. And that to bring new tubes to the level of the good old tubes just a computerized regimented process can't really match. It hasn't yet. It sounds like it is still is a human endeavor to make the best tubes. I have had several tubes and can hear a big improvement with my NOS over new stock. Anyway it would be nice if it does.
My experience indicates that new tubes are as good or better than old tubes in most cases, and since there are new designs that hadn't existed before now it renders that argument moot for those examples. I use Psvane 12AX7T-IIs in my hifi and guitar amps that I believe are better than any old stock 12AX7 I've used, and KT120s are amazing, didn't exist until recently, and have been adopted as a standard tube by some heavy hitter amp companies. The myth of old tubes being better is simply silly...they may sound different, people might prefer them, but design, construction quality, and consistency is fine for new tubes from many manufacturers.
Here's an interesting tidbit from the Atma-Sphere FAQ page:
"Atma-Sphere equipment is designed to work with commonly available tubes, making our products easy to live with. The 6SN7 tubes we use are produced in China but there are many aftermarket versions available. The output tubes are Sovtek, Svetlana or Chinese. The miniature triodes used in the preamps such as the 12AT7 and the 12AU7 are usually Chinese. Other types of tubes may be available on request."
I have no clue but based on what I know from what I hear I am with the wolfman on this. New tu.bes are not all gloom and doom like most new things are often regarded to be by audiophiles. I'm sureI can guess which side the sellers of expensive NOS tubes are on.
More audio twilight zone rumor accepted as fact.
Or, show us the facts to back up the assertion?
On off generalized observations have some value but clearly do not tell the whole story.
A lotta folks think all tubes sound the same, or essentially the same. Wouldn't vendors selling new tubes be inclined to market their product as being superior to NOS tubes, just like the NOS tube vendors, you know, for the profit to be made? Gosh.....another audiophile debate in progress. As for myself, I'll stick with WWII tubes from Sylvania and Tung Sol. Y'all can divvy up the new stuff. :-)
While it's certainly possible to have an individual craftsman make an audio vacuum tube, the tubes from the golden age of tubes were made in highly automated factories that practiced tight quality control.
The Blackburn Factory
Thanks Wolf except MY experience has not been as good, at least the last two times out. I sure hope the third time is the charm. This time I purchased the one year warranty for an additional 20% of the tube price. The last two pair didn't last beyond 3 months, 6SN7 in a pre output stage. Maybe an unusual experience, or something wrong with my preamp, for sure not the latter, the problem is tube quality.
I test ALL tubes I purchase prior to installation and keep a log of the dates installed. In the case of the first two sets, when I noticed noise I checked them out and the transconductance had gone South considerably, not a short, the tubes just didn't hold up, one was marginal the other tested weak and replace. The manufacturer sent me another pair. These lasted a bit longer, 5 months but certainly no more than 1500-1800 hours and I'm being generous. When I installed the most recent tubes a few days ago I tested the old stock Sylvanias I had in the pre-amp that were installed a little over a year ago to replace the failed tubes. They tested stronger than than the new tubes I just purchased and the same as the day I installed them. Unfortunately these very nice Sylvanias don't come close to the sound of the Chinese tubes, it ain't a subtle difference for sure. For 250.00 is it unreasonable to expect at least 4K hours of life or more? Or is this the new normal or is my experience unusual?
I think you should avoid the 6SN7s from that manufacturer as clearly something's wrong...but preamp tubes or driver tubes generally should last a very long time. Also, 250 bucks is some large cash for 4 driver or preamp tubes...sort of my lifetime preamp tube cost, although I can see (at thetubestore anyway) 6SN7s seem pricier than some other preamp types.
You haven't found the right modern tubes then? Emission Labs and some of the special Shuguang (nature sound range) are superior to the best vintage tubes IMHO. But I guess you are stuck if they don't make the tube you need?
I think the vintage tube obsession, unless you cannot find a good modern version, is bogus.
Nearly all the vintage tubes I have had over the years sounded Dark, or metallic, grainy or probably too fat or overly saturated. Try the mesh plates from EML. They are wonderful (and expensive!) but the nature sound are different sounding but as good and probably a lot cheaper than the EML
Was was told once a while back by a 90 year old English tube guru who also worked in tube manufacturing back in the early days, I think he maybe RIP by now.
He said to me that todays tubes will never match a good NOS tube, because back then they used lots of Nickel in the manufacturing process, and today they don't so much if any as it is very poisonous.
New production tubes that I can vouch for
2) Psvane, particularly their top level W.E. Replica series.
3) Shuguang, their treasure series.
These can compete with the best tubes of any era in my opinion.
There are some very good NOS tubes to be certain but there are lemons in that niche as well.
I've heard their 845 and it sounded better than NOS RCA 845 in a friend's SET amplifier. I use the Psvane 101D Hifi series tube in my preamplifier. People who've heard both say the W.E. 101D version is significantly superior ( and the Hifi version is very good!).I haven't heard their 300b but again it's said to be quite good.
I confess I use Mullard CV4024s, but mostly because the JAN Phillips 12AT7s they replaced self destructed after about a month, and I like the "start-up flash" the Mullards display...we need more tubes with that start-up flashing...it's exciting. Note that the EH 12AT7s were fine, I was simply overcome with curiosity. I do like the new Mullard 12AX7s in my Burriss guitar amp, but they, sadly, don't flash on start-up.