Tubes to Die For
If you own tube gear, you probably already know that choice of tubes can make a major sonic difference. Each tube brand seems to have a unique flavor of its own. And the right tube for a give circuit can catapult any amp or preamp to an exalted state - far beyond its stock sound.
I've been a tube roller for years, substituting tubes for the stock complement in every product that crosses the threshold of my listening room. This is an open invitation to join the Tube Roller Society and experience the joy of tube cooking!
The resurgence of vacuum tube audio, especially in the past 10 years, has seen new demands made on suppliers for a dependable sources of tubes. Very few manufacturers have been willing to live with the uncertainties implicit in using New Old Stock (NOS) in their products. Instead, new production from Yugoslavia, China, and recently Russia, has been relied on. As tube rollers, we are not bound by the same constraints. We require small quantities of a particular type, twos and fours, and are determined to find the best sounding devices from whatever source we can.
In the US and Western Europe, tube making technology matured in the 50s. Not surprisingly, vintage Siemens, Mullard-Osram (MO), Telefunken, Philips, Sylvania, GE, and RCA represent some of the best tubes ever put on this planet, and are well worth checking out. However, in the 60s some production was shifted to Eastern Europe (e.g., Yugoslavia and Hungary). Also, the Russians and Chinese never stopped tube production. The Russians, in particular, are responsible for pushing tube technology forward, as they incorporated tubes into everything military from MIG jets to tanks. Tubes built to Russian Mil specs are not only sonically excellent, but because of the favorable dollar to Ruble ratio, they are also something of a bargain.
NOS, in this country, is pretty deep for some tube types. Much of the plentiful stuff comes from military salvage; easy to spot in most cases because it's stamped as JAN: Joint Army Navy. It's easy to loose your shirt in this business. Some NOS types are either over-hyped and priced accordingly, or aren't what you think they are. Much of the stuff that's stamped as Telefunken from the 70s was actually produced in Yugoslavia. The label "Telefunken" doesn't automatically guarantee a great sounding tube.
The following tube brands are culled from my many years of listening experience and make up my personal pantheon of "tubes to die for." These are the tubes I search out for my personal collection.
1. The 12AX7A/ECC83. This high-gain, dual-triode, preamp tube is ubiquitous. I'd venture to say that at least 80% of tube gear produced in the last 40 years contains at least one 12AX7. Stay away from Chinese production! They are typically bright and harsh sounding. The Yugo (Ei Factory) sound a lot like vintage Telefunkens. The Russian "Sovtek" 12AX7WXT is also excellent. It is available from:
New Sensor Corp.
20 Cooper Square--4th Floor
New York, NY 10003
Tel.: 212-529-0466 1-800-633-5477
My all-time favorite substitute is the somewhat lower gain 5751, which is listed in the tube manuals as a "special type 12AX7." It was originally commissioned by the US Military as a low-microphonics tube for use in field radios. The GE NOS are very good. I recently saw an ad from New Sensor Corp. for JAN GE 5751s priced at $4.50 for single pieces. Sylvanias are also good, but beware though, I have not had good results with the RCA 5751. The king of the hill in this category is undoubtedly the Sylvania Gold Pin. Hard to locate...but if you find it - buy it - or at least tell me about it.
2. 12AT7/ECC81. I haven't had much luck with this type. I've weeded through a lot of brands to arrive at the following two recommendations: The premium Chinese from Golden Dragon; available in the US from VAC/Tubes By Design. My favorite of the lot: the Yugo (Ei plant) version, which will hopefully become plentiful again stateside in the near future.
3. 12AU7/ECC82. Most brands in this family are simply terrible. A typical 12AU7 sounds either euphonic or bright. I've discovered one specific brand that is so head-and-shoulders above the rest, that nothing else really matters. You've absolutely got to try the "East German" RFT brand. Gold Aero (Tel.: 818-841-5641) offers this tube in both Premium and Platinum grades. It's more refined, better detailed, and more spacious than any other 12AU7 I've ever heard.
4. 6DJ8/ECC88. I'm not really that keen on most vintage tubes in this family, including most German and Yugo brands. The clear winner in the affordable range of the price spectrum is the Sovtek 6922. Much better is the Russian Military 6922, which is available from LAMM Industries (Tel.: 718-368-0181, e-mail: firstname.lastname@example.org). The absolute best sounding 6DJ8 brand (actually a close cousine to the 6DJ8) known to me- a gift to mankind - is the Siemens 7308 Gold Pin. Suave and liquid, it is well worth whatever Gold Aero's Frank Morris charges for them.
5. Power Tubes. Since this is an exceedingly large topic, which requires lots of space to do justice to, I'll merely take a quick stab at it with a couple of "must hear" recommendations in the ever popular EL34 family. The Gold Aero E34L qualifies as probably the best sounding brand since the original Siemens. On the beam power tube side of the fence, my favorite is the MO/GEC/Genalec KT77. More magic overall, than the KT88, in my opinion. Hard to find and expensive, but well worth it. Limited supplies exist. Be sure to check with Gold Aero.
One final caveat: the sound of any of these tubes is partly dependent on the actual circuit and system context they're used in. So do plan to experiment... and above all else: do have fun!
Keep on Rolling!