Why Can't Tubes Be Mass-Produced Cheaply?

Fro Dan_ed ,

I agree, but that middle is so important, there is some reality to be gained and some beauty lost. Top extension invites harshness, particularly with vintage gear. I will occasionally de-Mullardize my system to find nuance and sacrifice some of the beauty. The beauty may not represent the sound of real music, but it's seductive none the less.

There is another thread about sound, amps and measurements, can we not measure a tubes midrange? I thought not.

Gregg

Dan ed is right. NOS are often not exactly as touted. NOS religion: another audiophile affection maybe?

Tested as NOS is more likely, not actually NOS.

I do own a few tubes I know to be NOS only because I have owned them since before the internet and AudiogoN existed; and I knew the person I bought them from had owned them for decades. I may only be the second owner. The boxes even look like new.

I have a good many tubes in my collection, don't know the exact number but at least two or three hundred. Among these are many current production small signal tubes as well as NOS.

Among my NOS are Genelex KT77, KT66, Mullard EL34, Brimar 12AT7, Mullard M8162 gold pin, Mullard 6922 gold pin, 12AX7 Telefunken, Siemens and Mullard, 12AU7 Telefunken, 12AT7 Telefunken and 6DJ8 Telefunken. (Can you tell I'm a big fan of Tele's :^).

I mention this before stating my opinion that there are no small signal tubes being built today that are equal to the best NOS. This judgement is made based on critical tube positions and does not pertain to EVERY situation in every piece of equipment. Like other things in high end, the type and design of the equipment and associated system play a big role.

For power tubes, the quality of new production gets closer (perhaps as Dan_ed suggests), in particular Wing C in 6550 and KT88, Wing C EL34 and Tesla E34L come to mind as favorites of mine.

Granted Mullard EL34 XF1 and XF2 are better than Wing C and Tesla, but it matters most when comparison is made in a critical position such as power supply of Aesthetix Io or Callisto. In an amplifier circuit (Wolcotts come to mind immediately), the EL34 JJ Tesla is more an option than a requirement when compared to Mullard El34 as power tube. The difference is there, but sonics could be argued.

When comparing small signal tubes such as 12AX7, 12AT7 and (especially) 6922, the modern versions from Sovtek and others are nowhere close if the comparison is made in a critical position. By critical position, I'm referring to small signal tubes in EAR 834, Aesthetix Io and Callisto, Audio Research Ref 2, input circuit (12AT7) of VTL 450, 750 and 1250 to name but a few.

I admit the Russians have made huge strides in tube quality. The newest Sovtek 12AX7 varieties are much better than years ago and for the dollar are amazing. The problem comes when these tubes are required to be ultra linear, zero microphonics and totally free of noise. I personally know manufacturers that screen Sovtek tubes to find the best, and the report I hear is about 5% are usable in critical phono circuits. Worse, when a few of these tubes get a couple of hundred hours on them, they degrade to the point of being unusable.

Other new production tubes from Russia and elsewhere, especially the 6922 variety are dismal. I don't know of a current production 6DJ8, 6922 that's really good. As old stock there's Telefunken 6DJ8, Mullard 6DJ8, Mullard 6922, Amperex 6DJ8, Amperex 7308 (Military) and others.

Unfortunately most audiophiles have figured this out, meaning the price of this particular small signal tube has gone through the roof. A hand full of years ago I could buy Mullard 6922 for $15.00, today they can cost $100.00. It's not greed driving the price, it's supply and demand.

Well screened used or new stock old production tubes are often not only quieter, more musical and less microphonic, they last up to 15 or 20 thousand hours.

Money always comes into the discussion, so I would like to make a point. Back in 2004 I replaced my critical input tubes on my Aesthetix Io with the best grade Telefunken (12AX7) that could be had. Now, four years later my sound is equal to the day those were installed, no microphonics, no noise and wonderful sound.

To keep new stock tubes that quiet I would have gone through a lot of screening and replacement, meaning wasted time and still suffering less than best sound.

Quoting myself

Like other things in high end, the type and design of the equipment and associated system play a big role.

A short list of exceptions, where NOS tubes had little impact (as I recall).

Shandling CD player (rare Western Electric tubes no better than stock).
Atma-Sphere's older amps, 12AT7 position (Yugo worked as well as Tele).
Scott Nixon's DAC, Russian as good as premium NOS
Wolcott amps, 6GW8 position in input, stock as good as NOS
Tube Research OD4 position in circuit, little or no change among brands
VTL 750, 6350 tube difficult to get big upgrades with swaps.

Probably a dozen other tests that I've forgotten, but you get the idea, and why people disagree with value of upgrade. I would not be surprised if someone got different results than mine on this "exception" list.

I think that it is quite possible that small signal tubes that can compete with NOS tubes could be manufactured again. Tube gear is very popular again so there is plenty of profit to be made and with the design and testing technology available today it could happen. They would be different from vintage tubes just as a car made in the 50s is different from one made today, but both have their strong points.

On another point, a vintage tube does not have to be NOS to sound as good as a NOS tube. Many tubes sold as NOS probably are used. But if they are still in like new condition they can sound as good as tubes that haven't been used and can last as long. Nobody kept track of most tubes made in the 50s and 60s to document if they were ever used.

To get good ones you either need to buy them from a reputable dealer who tests them or take your chances buying on ebay (where there are both reputable sellers and crooks) and test them yourself. There are pros and cons to either strategy.