[yeldarb]

I just recently bought a factory matched pair of NOS XF2 Mullard, with dual getters.  I had been using Winged "C", which I like, and thought pretty decent.  Tried the newest Russian Mullards, too.  The NOS tubes sound so much better than my previous tubes, that it is like my equipment was replaced with much more expensive kit.  Lots of detail that I just didn't hear previously.  Played an old favorite and the brush on a snare, can now be heard as 2 brushes, with an audible soft double strike.  No blurring of the sound at all.  Sure would be nice if someone made a new tube with the same quality as these 50 year old tubes.

[mresseguie]

I keep reading about how the NOS tubes are so much better, but I do not understand why newly produced tubes are so inferior. Does anyone hav a good explanation?

[yeldarb]

Most of what I read points to the quality of metallurgy, then vs. now.  Glass is glass, so it can't make much difference.  But there is a difference.  For that matter, why don't all new tubes sound the same regardless of brand?  How many Mullard copies are out there?  If they are copying the design, then any difference has to be the metals. 

[restrav]

it is entirely possible that QC is not up to par or the companies producing tubes now are just using inferior process or material ... but the sciene of metalurgy is now so so so much better even comparing what is possible to to do now to 5 years ago is a joke. so the potential to make products that are superior to NOS is there, i have no idea if the companies are using this potential or not. i would trust your ears though. dont trust what audiophiles say. most if them are idiots who like shiny things and buzzwords. and DSD is not the only buzz word. NOS can be a buzzword too.

[Anji12305]

The original EL34 was a true pentode.
The 6ca7 variant, which can be fitted to most amps that accept an EL34, is a kinkless tetrode and is wired differently. This is particularly evident if you run yoor amp as a triode emulator.

[lancelock]

I'm no expert but I've read that the manufacturing process during the time period that the best tubes were made was a bit hazardous. Some of the materials used:

Lifted from a 1940 RCA tube manual, here are just a few ingredients in receiving tubes: barium, caesium, chromium, cobalt, lead, mercury, strontium, thorium, etc. Radiation? In the good ole days we didn't have to worry about work place safety.

[FullRangeMan]

I keep reading about how the NOS tubes are so much better, but I do not understand why newly produced tubes are so inferior. Does anyone hav a good explanation?

The current manufacturers dont know anymore how to made the wires for the tube in any brand, clearly there was making secrets that dont appear in the tech manuals from the factories, the engineers keep it only in his minds.
Sad

[RPM123]

I just recently bought a factory matched pair of NOS XF2 Mullard, with dual getters.  I had been using Winged "C", which I like, and thought pretty decent.  Tried the newest Russian Mullards, too.  The NOS tubes sound so much better than my previous tubes, that it is like my equipment was replaced with much more expensive kit.  Lots of detail that I just didn't hear previously.  Played an old favorite and the brush on a snare, can now be heard as 2 brushes, with an audible soft double strike.  No blurring of the sound at all.  Sure would be nice if someone made a new tube with the same quality as these 50 year old tubes.

I installed a quad of Sophia Electric El34-ST ("long life version") tubes in my AVA Ultravalve a few days ago and I am very impressed by the sound as they break-in. Compared to the stock EH 6CA7's that come with the amp, the mids are much clearer and the frequencies are more extended. Tonality seems more accurate and the sound is more dynamic. Low level listening is better as well. The stock tubes are about a year old, so I am not sure how much if any of the differences are due to tube age. However, I do not recall the amp sounding any better prior to installing the new tubes. They are expensive at $125 per tube, ( ) but I was able to save some $ on a special one day sale offered by the company. Link to tubes: http://www.sophiaelectric.com/pages/se/el34.htm. They are also being offered on AudiogoN with a 2-week return policy. It's all relative I guess, since I have tried various cables over the years that cost as much or more, many of which did not impact the sound to the degree as the Sophia tubes have.

[DaveC113]

I just recently bought a factory matched pair of NOS XF2 Mullard, with dual getters.  I had been using Winged "C", which I like, and thought pretty decent.  Tried the newest Russian Mullards, too.  The NOS tubes sound so much better than my previous tubes, that it is like my equipment was replaced with much more expensive kit.  Lots of detail that I just didn't hear previously.  Played an old favorite and the brush on a snare, can now be heard as 2 brushes, with an audible soft double strike.  No blurring of the sound at all.  Sure would be nice if someone made a new tube with the same quality as these 50 year old tubes.

I've tried all those tubes and would agree. I also have some Japanese production that were made on Mullard equipment with the seams on the top of the tube, these or RFT are probably the best values.

For new tubes the GL kt77 are excellent, and I've heard the more expensive stuff like Black Treasure, etc are also very good but I'd rather stick with NOS for the reliability. 

[Photon46]

I keep reading about how the NOS tubes are so much better, but I do not understand why newly produced tubes are so inferior. Does anyone hav a good explanation?

Just to get a sense of the manufacturing advantages economy of scale provided previous operations compared to the small production scale of current tube manufacturers, take a look a the "Tube Tours" on Vintage Tube Services website. Look to the right of the tool bar headers for the drop down menu. Lots of interesting photo documentation showing how they used to do it at RCA, Mullard, Telefunken, Amperex, etc.: http://vintagetubeservices.com/selecting-your-tube-is-an-art/ T

Contrast the older manufacturing environment with what passes for a large scale operation in today's world: http://psvanetube.com/wordpress/psvane-tubes-factory-tour/

[mkane]

 New manufacture Tung-Sol from McShane not bad.

[Wind Chaser]

Wall of Sound EL34-family Tube Comparison - by Tim Smith

http://wallofsound.ca/audioreviews/tubes/el34-tube-comparison-with-tubes-supplied-by-www-thetubestore-com/

[rotarius]

Wall of Sound EL34-family Tube Comparison - by Tim Smith

http://wallofsound.ca/audioreviews/tubes/el34-tube-comparison-with-tubes-supplied-by-www-thetubestore-com/

A nice review although I don't agree with the rankings.  The TS is decent but in now way as good as he says.  I guess a lot depends on the system, in mine, the midrange was quite dry and strings just sounded a bit too steely for my liking.  The Mullards have much better mids.

[JackD]

I tried a set of the TS's too and felt the same way.  Went back to the Winged C's after about 50 hours when they didn't smooth out any.

[rotarius]

The EH EL34 gets no love for some reason but I really like it.  It beat out both the KT77 type when paired with a warmish input tube in my amp.

[Wind Chaser]

The EH EL34 gets no love for some reason but I really like it.  It beat out both the KT77 type when paired with a warmish input tube in my amp.

Yeah, I think there's something to be said about synergy among the various tubes at play in conjunction with the design of the amp. Anyhow I ordered the Gold Lion KT-77 based on his recommendation since I will have the same amp he has in the next few days. I may or may not agree with his assessment but in the end, it's always nice to have options in the way of a variety of tubes on hand. 

[rotarius]

Yeah, I think there's something to be said about synergy among the various tubes at play in conjunction with the design of the amp. Anyhow I ordered the Gold Lion KT-77 based on his recommendation since I will have the same amp he has in the next few days. I may or may not agree with his assessment but in the end, it's always nice to have options in the way of a variety of tubes on hand. 

Agree 100%.  Circuit design and input tubes are the big variables in how power tubes sound.