Gonna disagree big time...with a vintage OR 2555x those JJs are tub city. IME anyway. The stock Tung Sol 34s sound good, definitely better than the JJ EL34L. Now, the JJ 6CA7s sound really nice.
Yeah, I really dig that tube. They’re much tighter, punchier, and more aggressive than EL’s. I put them in my Triple Rec and they kill. I wanted to like the 6L6’s better because, well, that’s the “recto sound,” but there’s just no comparison imo. The E34L’s just lit a fire under it’s ass. The 6L6’s sound drab in comparison. And for anyone considering trying it in a Recto, Eurotubes did warn not to use them in silicone, only tube, because they do run hotter than EL34’s. For the record, they’re tight enough on tube setting anyway. Probably tighter than 6L6’s on silicone setting.
KT90’s, huh? Interesting. I don’t really dig KT88’s, I thing they’re overly dry and tight. But a huge sounding EL34, that sounds awesome. When you run different pairs in this amp, do you put the same type in 1-2, and 3-4, or like a simulclass amp?
It's been a few yrs since I had the 2555x but from what I remember there's some instructions printed on the chassis to let you know the bias range. Points and bias screws for both sides are outside so you don't have to pull the chassis. The pairs are 1-2, and 3-4 which is different from a vintage Marshall where you could run the 2 inner or 2 outer tubes if you wanted to go from 100-50w. The KT 90s are like 50 per tube though, not cheap but I think they are just awesome.
In this amp, I agree..those Tung Sol 34s come stock since that's what mine came with. Of course, I then tube rolled with my Cs, Siemens and vintage Mullards and they didn't sound any better than the Tung Sol 34. Which is the truth about new production amps IME...they just aren't sensitive to tube swaps like the vintage versions.
