Sound of new production tubes

[My3gger]

Hi,

over years i see many claims of NOS tubes sounding much better than new production. It doesn't make sense when comparing for example one type of NOS to well made new production tube, when both are within specifications and really the same type. Not something like circuit designed for E88CC and then comparing NOS E88CC to new 6N1P.
I've done extensive listening tests over a period of few months with a few NOS Tesla EF806 and Svetlana EF86, compared to new EH EF86, both wired as triode in RCA BA-2. There was no difference in sound between them, DC and AC readings were very close too except of one Svetlana which was almost dead anyway and i could see it wasn't mechanicaly made well.
The only time i could hear quite big difference was in Redd 47 when comparing new 6N1P to Siemens E88CC. Of course this two tubes are quite different and i was expecting difference in sound. It showed as 6N1P having a bit more gain, sound was not as focused as with E88CC, a bit grainy, so it really was like listening to another lower quality preamp when using 6N1P. Can't remember measurements well, although they were not that much off.

Ian Bell has a paper with good comparison of 6SN7 to 6CG7 in mu followers, with NOS and new examples. It goes into details like grid current, measuring harmonics, levels, etc.
Another test by him was done with ECC83, this time new production tubes only and global NFB. This one is maybe even more revealing because it shows ECC83's distortion when compared to output tube is so low, that sound of ECC83 used in typical mic pre is completely masked by output stage distortion.
Some of my own tests with ECC83s in guitar amp inputs showed NOS or not, difference comes mostly from using tubes with different gain. One amp sounds a lot better with new EH ECC83 compared to Siemens ECC83 because EH has more gain and this is what people wanted. It makes me suspect NOS in guitar circles sound better just because many new ECC83s have a bit lower gain.

I know tests like this are not scientific enough, mostly based on experiences, but it does seem like well made new production tubes sound as good as NOS. The only real difference i can observe is need for a bit more selection and lower expected lifetime for new production tubes, if comparing to really good NOS examples. Not fakes or already well used "NOS" like from eBay, etc.

What do you guys think, am i right about it? Were there any special ingridients in NOS that make them sound better, or is it just a matter of selecting good new production examples sellers don't want to talk about?

 

[ruffrecords]

I have always preferred new production from Russia because they were making tubes at the same time as the famous NOS types were being made, using similar production methods with people who were well practised at managing and maintaining production. When the rest of the world stopped making tubes, the Russians carried on. So it is reasonable to assume that current Russian production still has the benefit of that hard won knowledge and experience and their tubes should sound very similar to the way the NOS types sounded when they were made.

The trouble with NOS tubes is they were made 50 or more years ago. They were never intended to be left for 50 years before being used. Nobody knows how tubes deteriorate over that period of time but it is reasonable to assume they do deteriorate. It is impossible to say if a NOS performs the same as it would have when fresh off the production line. The the probability is they do not.

It is also well known that, back in the day, each tube type was made by several manufacturers, each using their own particular production processes and often slightly different implementations of the same tube.

On this basis, it is hard to see how there could be anything special about NOS tubes compared to current Russian production ones.

As I have mentioned before, I have tested hundreds of NOS tubes and found a large variation in performance (the only exception I have found are NOS 6CG7 made by Matsishita  which have a  very consistent and higher distortion). I have tested almost as many current production Russian tubes and found them to be much more consistent than NOS.

NOS types seem to be particularly poor when it comes to noise and microphonics. I suspect the latter is due to general mechanical deterioration over the decades. I have tried burning them in for a few days but this made no improvement.

It seems to me that the only people who benefit from the hype surrounding NOS tubes are the people selling them.

Cheers

Ian

 

[CJ]

many of the chemicals used to manufacture NOS tubes are now illegal,

so it is impossible to make a tube nowadays that will be an exact match for the old stuff,

however, who knows what the Ruskies are doing, using old school strontium 90, coating heaters and cathodes with Barium ions, tampering with

go to the KCA tube site and read through the various descriptions of various NOS types, read VTV back issues, plugging and playing is probably the most fun you will have as far as circuit tweaking, but today it is a rich man's sport,

try some RCA black plate 6L6 tubes against some JJ's, or some Amperex 6BQ5's against EH , some Telefunken smooth plates in your stereo against some Ruby's, put some Genelex brown base KT66's in your JTM 45 and see if you have ever heard midrange like that, ever hear a Mullard GZ34 in a 1965 Fender Deluxe Reverb? take  out a student loan from citibank and  live a little,

 

[bibi]

How does a rectifier tube affect the sound of an amp other than changing the operating voltage? 

One of the main problems with new production rectifier tubes appears to be that they do not exhibit the same resistance under load as their forebears.  I cannot find a 5Y3 new production that functions similarly to a NOS version for instance.  In repair situations the end voltage is often far too high which causes a number of serious problems beyond the "tone" issue.  Luckily 5Y3s are still relatively reasonably priced and for customers who just want the sound and not the expense, a pair of silicon diodes and a high wattage resistor works just fine.

 

[CJ]

modulation of the power supply,  attack and release,

 

[ruffrecords]

How does a rectifier tube affect the sound of an amp other than changing the operating voltage? 

The answer is it depends. If you are talking about a claas B push pull power amplifier driving a speaker, then it makes a lot of difference, The high resistance of the rectifier tubes means that when the music is loud the power supply will sag and this affects the sound.

If you are talking about a class A line amplifier then the answer is  it will not affect the sound. Properly decoupled class A amplifiers draw an essentially constant current so there is no sag.

Cheers

ian

 

[My3gger]

How does a rectifier tube affect the sound of an amp other than changing the operating voltage? 

By marketing hype maybe? I'm sure you know that in class a where most studio tube gear like preamps are biased, sag on PSU lines is almost non existent.
I've tried one of Drip's preamps where he used GZ34 as a rectifier and two OA2 voltage references for one channel. All this was only causing problems from GZ34 on, the only thing that worked well were AC heaters... Quite similar preamp from D.W.Fearn uses simple RC filters with cap decoupled zeners for HT, heaters are regulated with 7812, phantom looks very much like Gyraf's G9. Simple and well working circuits, i'm pretty sure he would and could use tube rectifiers if they would sound any better than silicon.
To me it makes sense using tube rectifiers in guitar amp repirs and restoration of old tube gear, silicon for the rest if needed at all.

p.s: You were faster, i get less than 1V of change on HT (RC filter into cap multiplier) in class a preamps with input signal and cheap DWM. Ripple at idle can be barely seen on 2mV per division with x10 mag...

 

[AusTex64]

<Were there any special ingridients in NOS that make them sound better?>

Cathode coatings.

 

[My3gger]

Wouldn't inferior cathode coating just make tube loose emission sooner? Is there any data to backup claim of superior NOS cathode coating? I will look into RDH if they give such data.

 

[BluegrassDan]

I think the new Russian tubes are fine, but they don't sound like the NOS Telefunkens I just put in my hand-built tube preamp or my LA2A. They absolutely sound different.

The Russians also don't sound like NOS Amperex, Mullard, Siemens, GE, Mazda, or RCAs. There is enough of a difference that I always use Russians for testing new builds, but always spring for the NOS flavor that will best suit what I'm after.

I will say that a matched pair ofRussian Electro Harmonix tubes are incredibly well matched. I have two matched pairs of 12AU7 and 12AY7 here on my desk that together are within .15db output no matter which tube is in any given position. That is beyond what one might typically expect from NOS.

 

[AusTex64]

Wouldn't inferior cathode coating just make tube loose emission sooner? Is there any data to backup claim of superior NOS cathode coating? I will look into RDH if they give such data.

I'm not a tube guru by any means, but Oliver Archut was. He gave me a good lecture about how cathode coatings were closely guarded secrets by the tube manufacturers, and it was lack of knowlegde about those coatings, along with availability of materials that seperated the modern tube makers from the companies of the golden age of thermionic emmission. Wish I had recorded it or taken notes. The old ham radio guy I buy vintage tubes from shares the same ideas.  It's this phenomena that leads me to suspect why tubes of the same type sound different from different manufacturers, and in a similar way. RCA usually sounds more bassy and mellow, Telefunken is clear and hi fi, GE is also clear and hi fi, Tung Sol is somewhere in the middle, etc.

I actually thought the "sound of tubes" thing was a crock of sh*t until I did some comparisons with an LA2A, using identical program material at exactly the same levels - nothing changed but the 12AX7's. I recorded the results then switched back and forth instantly. It's the only way I've found to truly hear these differences. And I could hear them.

Now a real smart tech I work with thinks it's a crock. He asked, "did you check to see if the bias point was the same with every tube swap?" That's a good point, and I should have considered that. But it still doesn't explain why different tube types from a manufacturer like RCA generally have a predictable sound. Which leads me back to cathode coatings....

 

[ruffrecords]

I'm not a tube guru by any means, but Oliver Archut was. He gave me a good lecture about how cathode coatings were closely guarded secrets by the tube manufacturers, and it was lack of knowlegde about those coatings, along with availability of materials that seperated the modern tube makers from the companies of the golden age of thermionic emmission.

I don't understand this. The Russians have been making tubes since the 'golden age'. They have more experience and 'secrets' then anyone else. It's the newcomers like the Chinese  and, untill recently, Hungarians, that don't know what they are doing. I wouldn't touch any of them.

Wish I had recorded it or taken notes. The old ham radio guy I buy vintage tubes from shares the same ideas.  It's this phenomena that leads me to suspect why tubes of the same type sound different from different manufacturers, and in a similar way. RCA usually sounds more bassy and mellow, Telefunken is clear and hi fi, GE is also clear and hi fi, Tung Sol is somewhere in the middle, etc.

There is no doubt some old tubes sound different. That does not mean it is the 'right' sound. Russian tubes are closer to what NOS tubes were when they were made, but NOS tubes have deteriorated over 50 years and most likely do not sound anything like they did when they were new. If you prefer the sound of NOS that is fine, but it is bad logic to conclude it is the 'right' sound.


Cheers

Ian

 

[gyraf]

Ian,

Where would you buy new-production Russian tubes today, if you wanted to be relatively sure of their heritage?

I may as well try some of them out, the NOS JAN-types are getting horribly expensive lately...

Jakob E.

 

[ruffrecords]

Ian,

Where would you buy new-production Russian tubes today, if you wanted to be relatively sure of their heritage?

I may as well try some of them out, the NOS JAN-types are getting horribly expensive lately...

Jakob E.

I use mainly 6922 and ECC83/12AX7 tubes. For the 12AX7 I use Sovtek 12AX7WA because I have found it to be the most consistently low in both noise and microphonics  (many NOS tubes are very microphonic). These are widely available. I get mine in the UK here:

http://www.hotroxuk.com/sovtek-12ax7wa-ecc83-valve-standard-4807.html

For the 6922 I use Electro Harmonix 6922 EH (I have also tried the JJ E88CC but I have found them to be inconsistent). Again, HotRox in the UK sells the gold pin version:

http://www.hotroxuk.com/electro-harmonix-6922-gold-pin.html

but I usually try to get the regular pin types which you can get from The Tube Store for example:

http://www.thetubestore.com/Tubes/6922-E88CC-Tube-Types/Electro-Harmonix-6922EH

I am sure there are sveral places in Europe that sell them but I cannot think of the names right now!!

Cheers

Ian

 

[gyraf]

Thanks!

 

[AusTex64]

I have also listend to Russian made EH and Czech made JJ 12AX7's. The EH were definitely closer in sound to the vintage (for lack of a better word) tubes I compared to. But I've still not heard a modern production 12AX7 in a Deluxe Reverb or LA2A that was as pleasing to my ear as old tubes from RCA, Telefunken, Tung Sol, Amperex, etc.

Regarding the life of tubes, I understand if they haven't lost vacuum they should be time capsules. Please correct me if that's not true. Thanks!

 

[ruffrecords]

I have also listend to Russian made EH and Czech made JJ 12AX7's. The EH were definitely closer in sound to the vintage (for lack of a better word) tubes I compared to. But I've still not heard a modern production 12AX7 in a Deluxe Reverb or LA2A that was as pleasing to my ear as old tubes from RCA, Telefunken, Tung Sol, Amperex, etc.

As I said earlier, if you prefer the sound of NOS tubes that's fine. As a wise man once said,' My pinion is worth exactly what you paid for it.'
[/quote]
Regarding the life of tubes, I understand if they haven't lost vacuum they should be time capsules. Please correct me if that's not true. Thanks!
[/quote]
There is plenty of evidence to the contrary. I have tested hundreds of NOS tubes. I have found that they are in general noisier than their current production counterparts, which clearly says something about the deterioration of the cathode coating, and almost without exception they are more microphonic which I suspect is due to long term relaxing of the tension in the grids.

Cheers

Ian

 

[gyraf]

..and you're quite sure that what you see is not because someone sold you previously de-selected goods?

I had experiences like that until I started buying wholw sealed boxes of JAN tubes: Yes, some of them are off, but nothing like what I was getting used to in buying "N"OS stashes.

I suspect very much that someone is skimming the market for goodones and letting the junk back into rotation...

Jakob E.

 

[emrr]

I'd agree with Jakob.  I've cleaned out radio station tube cabinets on several occasions, NOS tubes that'd been there as long as 70 years, station testing/matching dates in pencil from the '40's '50's 60's, never had a funky tube out of those lots. 

 

[fazer]

I have some telefunken 12ax7 smooth plates that are superior in a phono preamp to any other tube I've ever tried so maybe its euphoria.  I don't know. The problem is that once they get noisy it's over even though they seem to retain the tone.