It really isn’t easy as a guitarist. You’re scouting around for a new amp, and suddenly the details of tube technology become an issue. Yes, there’s the choice of power stage valves to deal with – but there’s also the preamp stage. Many feature the 12A7X/ECC83 valve. But as the shoot-out video below proves, all 12AX7s are not identical…
ECC83 = ECC83?
The video below was produced by Johan Segeborn. If there’s one YouTuber whose comparison tests I believe in, it’s Johan’s. There is hardly any other video maker who compares things so authentically. He also comes across as a rather modest guy and doesn’t load the video with jumpcuts all the time. He takes his time. In this 8 minutes of video, he compares a total of 17 tubes for the preliminary stage.
Among the tubes compared here are the 12AU7 (ECC82) and a 12AT7 (ECC81) tube, the rest being the 12AX7 (ECC83). The 12AX7 is the most widely used tube in this application. But as we all know, tubes of the same type do not not sound identical just because they have the same design. It’s like with a Les Paul guitar: Not all LPs sound the same.
Depending on the manufacturer, this video shows a significantly different sound. The makers include: Mullard, Philips, Tung-Sol, Audio Classic, TAD, Mesa, Marshall, Raytheon, Ultron, Ruby, Electro-Harmonix and JJ.
One advantage of changing the preamp valves in your amp (compared to swapping out the power amp valves) is that you do not need to bias them. That means you can ‘plug n play’ without having to manually set up the bias each time.
Johan’s video shows just how different these tubes can sound. Before watching, I knew there were going to be significant differences. But I would not have thought that they would be this big. I’ll have to go back and think about what tubes might be good for my Plexi. Damn you, Johan!