NOS stands for New Old Stock: tubes that
where made a long time ago but never used. There is no official rule for
how old a tube has to be to become NOS, but most of the time it is applied
on tubes that were built either in the US or Europe until the mid 80's
(when the production stopped).You also have Old Stock tubes, which are the
same as NOS but but these are used.
The quality of the tubes is not affected when they just lay around doing nothing. As long as the pins are not suffering from oxidation, which rarely is the case. Many people prefer NOS over current production tubes, simple because back then they used higher quality materials and in most cases higher standards. Many of today's production tubes are built on machines that were used by the big companies (like Philips and Telefunken) many years before.
Right now there are only a few factories left that produce tubes and they are all based in Eastern Europe (JJ in Czech Rep. and Ei in Yugoslavia), Russia (Svetlana in St Petersburg and Sovtek) or in China (Sino). And only JJ and Svetlana are capable of producing tubes that come "close" in tone and quality when compared to NOS tubes.
Although Ei, for example, uses great Philips machines and are capable of producing a ECC83/12AX7 preamp tube that is based on the famous Telefunkens, it sounds really good but it's quality is so poor that it will go microphonic in any guitar amp. And thus renders is useless for 99% of it's for us guitar players. Too bad cause the sound is really good, especially when used for high gain application, but the microphonics are aw full.
Some people like the newer Sovteks and their Electro Harmonix tubes. These are certainly better then their production in the 90's but imo not as good sounding as JJ's or Svetlana and for from NOS tubes. And Chinese tubes... well I'll leave that to the people who can only dial their gain to 10.
The following article
was written by Myles Rose of
Guitaramplifierblueprinting,
and copied with his permission.
NOS TUBES – The hype, myth, and reality.
Are NOS tubes any better or different than the new tubes
made today? Many folks cannot seem to tell the difference. After a recent
batch of new tube testing, where NOS tubes are used as a standard for some
areas of the test, I thought some explanation of this subject was
warranted.
Why can’t some folks hear and feel the difference? This
is actually pretty easy to explain. A lot of today’s players, especially
the younger ones, have never played an amp from the Fender Tweed era.
These amps had simple circuits and lower gain. Playing one of these amps
yields a feel that cannot be approached in higher front end gain amps. The
higher the gain, the less articulation, harmonic content, and frequency
response in many cases. These vintage design amps also would sustain at
low volume levels, or most any volume level.
You don’t want to
accept this? Try this simple test. Take your high gain amp, turn the
master way down and the gain pretty far up. Hit a nice power chord, and
while the chord is ringing, hit a note or two … in a lot of amps one will
barely hear the added notes. Crank the gain all the way up now. In a lot
of amps, the sound has become so indistinct, that even chord changes are
difficult to discern.
Vintage amps and vintage circuits have a
different tone and the amp plays differently. Most of the younger
generation have not had a chance to play some of these amps, if any of
them. It is like making comments on how fast a Ferrari BB512 is as you
watch from the curb. It is different than making the comments after
sitting in the drivers seat.
So, the hype of NOS tubes? The hype is
generally the comments from folks that plug a nice NOS tube in their very
high gain amp and crank it up. These folks need to spend a bit of
time and also learn what to listen for such as harmonic content, life in
a note that is held, and body and depth in the
notes.
The reality of NOS.
There are many
factors, but economics and law suits and liability, and the EPA are two of
the today. Liability? You bet. The money goes to safety. Cars … airplanes,
etc. This boils down to STEEL. Yup, That stuff your car body is made of, turbine blades in jet engines
are made of, etc.
Steel was really coming into it’s own around
World War 1. Submarines needed metals that could be compressed at depth
over and over. Airplanes need crankshafts that could stand up to their
job. Metallurgy continued to improve. There were great steel companies
such as US Steel in the USA, and the fine Swedish and Finnish steels.
Today, most of the US steel companies are gone. The great controlled steel
recipes are reserved for more critical applications such as aerospace or
the automotive and aircraft industries, where a lawsuit is just around the
corner. If a tube fails in an amp, who cares?
The EPA makes
production of cathode coatings and like items more costly and at times
almost impossible.
Then, there is economics from a geographic point
of view. The Russians are not cranking out defense equipment any more.
They have no money. One batch of steel is completely different than the
next batch. In Eastern Europe, it is the same when it comes to the quality
control of metal alloys. There is little economic reason to have high
quality control standards in a cheap vacuum tube.
When tubes were used
in scientific, medical, and defense equipment, quality was an issue. Today
it is not an issue.
So, where does this get us?
Recently I tested some new Sovtek 12AX7LPS
tubes. These brought this subject home. Using a myriad of test equipment,
it was found that in one area, these tubes did beautifully. This area was
simple gain. Using the Vacuum Tube Valley small tube characterizer, these
tubes produced the “gain” of 100 or over a bit in some cases, just as a
12X7 should. BUT … a tube has more than one factor.
Gain. Think of
gain as horsepower. Just like cars today, some have a lot of horsepower
via small displacement and turbo charging. It took a few decades to get
back horsepower into cars on the road after the gas crisis of the
seventies. There are big dollars in cars, and consumers wanted horsepower
and performance. Over the years, even with CART standards, we got back
horsepower. We got little else initially, but with all those consumer
dollars at stake, by the late 1990’s we also got back overall
performance.
Today’s tubes have gain. They may not have linearity
(driveability), but they have gain, in varying degrees.
Output.
Think of this as torque. This is one thing today’s tubes are lacking.
Output is what pushes your signal though an ever expanding load of
resistors, signal processors, effects, and tons of additional circuitry in
your signal chain. Look at these three and four channel amps, where V1
(your first gain stage and the mother of your tone), is expected to drive
the rest of that mess of a signal path.
You can look at that
Sovtek 12AX7LPS that had a gain of 100 or 105 in some cases, out with an
output of 0.5 – 0.6 millamps, it had half the expected output of a good
12AX7.
Today’s tubes do not have output …. No
torque.
Transconductance. Think of this as acceleration. The
ability to react to a signal (or green light) and get off the line fast,
slow down, speed up, and take the corners. This also relates to how linear
an tubes response curves perform. With a nice linear response, note
changes have the same levels. If this factor is lacking, you are fighting
your instrument trying to compensate for it’s non linear character. Again,
the Sovtek 12AX7LPS did not perform even close to 1957 or NOS
spec.
By the way, the Sovtek 12AX7LPS is a great tube by today’s
standards and performs better than a lot of them out there.
So, this third factor, TC or
acceleration, is also missing.
Where does
that leave us?
NOS for one thing is a short term option. Short term? Sure, this is limited stock. The reason the 50’s tubes fare better than the 60’s tubes in some cases, and the 60’s better than the 70’s, and so on, was that in the 50’s, more tubes were used for critical applications. They had better metals and QA.
There are some points of light on the horizon too.
Well, thankfully, the Chinese have money and are putting it into consistency. They see the economics of the music business as a strong market with MTV, VH1, CMT, and more amp makers than ever before in music history. Each Chinese batch of 12AX7’s is better than the next. Their “torque and acceleration” are currently better and closer than any of the Europe tubes generally. Their consistency is also the highest.
The last hope lies in the hands of folks like Aspen Pittman (Groove Tubes). GT spent a LOT of money to remake a tube called the 6L6GE as an example. This was not an easy task, taking years. Using the original tooling was not all that hard (Aspen just bought it from a factory when it shut down), but setting it up properly was another costly story. Then the daunting tasks of those materials in the recipe was the issue. Well, he pulled it off, after many years and many dollars. We now have a great NVM ( I coined that NVM by the way … new vintage manufacture) output tube. It is not cheap, but it can be produced over and over now. I am not too worried personally on how long this tube can be produced, as I am 53, and I saw enough tonnage of original plate material metal to make enough of these to last at least my lifetime!
There are other folks that work directly with some of the major tube factories. Some do this for a love of tone and amps, such as Aspen, some do it for economics. The folks that do this for economic reasons seem to take shortcuts which show up in the end result product, as is the case in some of today’s preamp tubes.
When it comes to new preamp tubes, keep in mind that today you have gain … although all over the scale and inconsistent. You rarely have the other factors, output and TC. If you know your preamp tube vendor, your chances with new tubes are much better. GT, as an example, tosses about 50% of their tubes, as they have to meet tests for output, low noise, and a lack of microphonics. That is part of the reason for their cost that some folks feel is higher than some untested tubes.
The bottom line here, is that NOS tubes were superior to the products made today. If you cannot hear this and FEEL this, turn down your gain, raise your master, maybe learn what to listen for, and perhaps have your ears cleaned.
If after all that, you still feel there is not a difference, then you are fortunate to have standards which are easily met. BUT …. You still cannot escape the basic math and seeing that the data on today’s tubes do not meet those of yesterday unless you have a vendor that will go through 1000 of them to find a few great ones.
P.S. I have called and written Tone Quest a few times. I have a number of friends and associates that are on their advisory board, and I was thinking that they may be interested in some real tube info, which at times is lacking in their publication. I guess my personal clients are not obscure enough for them, or perhaps there may be some other reason they do not return phone calls or emails. In any case, if there is somebody that may know why they are not interested in some tube information, maybe you can let me know as they don't seem to have the time to respond.
Myles - Guitaramplifierblueprinting.