I I've had a Lectron JH-50 amp since 1992 and throughout the years, I tried whatever EL-34 tubes were available. However, I've never tried any NOS tubes.
I've used a lot of Sovtek and Electro-Harmonix tubes because of their liveliness. I've heard criticism about the (weak) bass they produce but I don't listen to the music that way and that never bothered me. Both tubes are highly reliable and last a long time. By the way, bias on my amp is on a lower side.
At some point, I started to buy Svetlana, and I liked them too, even though they sounded different (more mellow and warm). Their reliability is also excellent.
I agree with people above who praise Psvane PHI - I think these are excellent tubes in my system.
About a year ago, I ordered Shuguang 6CA7-T directly from their factory store (AliExpress). I replaced Psvane with these and never went back. They produce a slightly warm (not like Svetlana), very clean, transparent and detailed sound throughout the whole spectrum. They produce pinpoint imaging, and they are very dynamic, dimensional, and atmospheric. I think Psvane tubes sound very similar and this is why I like them both more than any other tubes I've ever tried. To me, Psvane and Shuguang tubes sound good with any type of music. However, I cannot evaluate their reliability.
I have a tube tester, and I do not wait until a tube dies - I replace tubes when they become weak. All Sovtek, Electro-Harmonix, and Svetlana tubes I have ever bought were tested and matched and I have never lost any of them. No other tubes could match reliability of these 3 in my system.
I hope this helps.
