All valves or tubes are not made equals

… or should we say : “All valves are equals, but some are more equals than others”. Most of the reasonnably priced tubes are of contemporary build nowadays. NOS tubes are now overly expensives. And a good deal of those (especially those found on eBay) might be Old Style but are not New at all. You may classify modern tubes in three categories :

  • – Tubes that are but remotely identical to their Old Style originals. As they are of poor quality, we won’t talk about those.
  • – Tubes that are of modern build, and made as close as possible to the original, sometimes with improvements (mainly a longer lifetime) due to the use of modern materials or techniques. This is our prefered kind.
  • – Tubes that are of modern build, and offering drastic improvements. A good example is the EML300B-XLS from Emission Labs. Higher maximum power, higher current rating, higher filament current, almost all its characteristics are different and/or improved. It is true that it can replace any 300B (with some caution thou) but it’s actually another tube. As those special builds are very expensive, we use those only at special customers’ requests.
Construction techniques and materials used differ from one factory to the other. Therefore your tubes brand choice has a real impact on your listening experience.

Some of the opinions expressed here were first found in amateurs’ or professionals’ websites, like or Mr John Templeton’s reviews among others. As our tests at acdc-audio showed those opinions to be exact in every bit, we’re happy to let you benefit from it, along with our own feelings or tests results. We hope that this will help you finding the tubes brand that suits your liking.