Indeed I was going to tell you what Joe did. The JJ E34L is a different tube, I think IIRC that the height is slightly longer than the regular JJ EL-34. The other cool thing is that the E34L comes in colors. Trelja and I preferred the Blue glass. I am not sure but I think the color helped with heat dissipation.
Unlike Trelja I never noticed the loss of bass or low end extension relative to other EL-34s. It possibly true and Joe is rarely wrong about all things audio. I haven't had the matched octets necesarry to make such a comparison in a long time.
I am just wondering outloud, if you might want to try the Gold Lion Reissue KT-77 at some point. When I get my equipment back, I was thinking about putting the KT-77s in my DA-60. I will report my findings should I endevor to make the switch, but my amp is not a JOR, so it may not be very useful to you.
I have never rebiased the amp because it has an autobias circuit built in, and I am uncertain if I can overide the autobias, and bias the amp manually. It would be a PITA in any event the amp is pretty heavy and I am not young anymore.