Burning in. The little glass bottles in front are older than I am. From left to right: GE 12AX7, Amperex Bugle Boy 12AT7, Sylvania 12AX7. They're sitting in my THD Flexi-50, a favorite guitar amp of mine for 17 years. This is the first time I've experimented with NOS (new, old stock) tubes. The results, after a weekend of burn-in, were stunning. It radically improved the tone of the amp.
Amazed that you can still buy the tubes. Must cost a fortune. (like everything else in hobbies, amIright?)
Well, there are still like five factories producing vacuum tubes - one in China, which produces the most, one in Slovakia which produces the new-production tubes I most frequently choose, and two in Russia, one of which is owned by an American company. There is one in the US, in northern Georgia, doing business as Western Electric, which is producing 300B tubes for the audiophile market. 300Bs are extremely expensive tubes, like $600 apiece. And the company also makes a hi-fi amp for them, which costs $15K.
But it's true that a lot of the knowledge and expertise that made gazillions of tubes in the US and Europe between the 1930s and early 1980s has been lost, which is why New Old Stock tubes are becoming increasingly valuable. The tubes made in those decades when tubes were essential to national defense have proven to be extremely durable, extremely consistent, and carefully tuned and constructed to do what they do as efficiently as possible while injecting as little distortion to the signal as possible. That was important when tube circuits were guiding missiles, detecting enemy vessels and aircraft, and running medical equipment.
Now, tubes are mostly a niche market comprised of musicians and audiophiles, and a lot of those musicians are guitar players who WANT the distortion, but don't themselves understand the science behind tubes except at a very primitive level. So manufacturers tend to emphasize signal gain and low headroom. The tubes distort easily, but in doing so they tend to flatten the sound, losing a lot of subtlety in the signal. And consistency and durability are not particularly important, because ultimately the manufacturers will sell more tubes if people are having to change them every year or two.
Amp designers can acount for some of these negative impacts, such that many guitar amplifiers don't benefit much from using old tubes. But for guys like me who favor vintage amplifiers (like my 1965 Fender Twin Reverb) or vintage designs (like my Flexi-50 or my GDS 18-Watt), the old tubes can have a palpable benefit. I knew this, from an intellectual perspective, but had avoided getting into that whole milieu because it can get expensive, and I hadn't really experienced how dramatic a difference it can make until recently. Partly that's because I had a steady, paying gig for 22 years that required I use digital guitar processing sent directly to PAs that emulated tube amps, rather than using real tube amps. Now that I'm not doing that anymore, I have more time to experiment with and utilize my tube amps.
These particular tubes were expensive at $50 each, compared to the $20 the Slovakian tubes cost, but not remotely as expensive as some of the more rare and desirable tubes such as the old European tubes like Mullard, Amperex, Telefunken, and Mazda. A pair of upper-end Mullard ECC83/12AX7s will cost about $400. The very rarest and finest strains will be over a grand. And that's for the little preamp tubes, not the big power bottles like the Tung Sol 6550 and JJ E34Ls in the back row in my picture.
So yeah, it can cost a fortune to deal with NOS tubes. On the other hand, most of the time they last much longer, so it's not as expensive as it might seem.
Western Electric says it's going to start making tubes for the guitar market, starting with the nearly ubiquitous ECC83/12AX7, and there is intense interest in that. But bet they will cost as much as NOS tubes or nearly so. Guitarists will buy them, because America, but that doesn't change the fact that so much knowledge about tube manufacture literally has died of old age with the engineers who made them possible. So the jury is out - way-way out - on whether they will actually be as good as the old tubes.
