EL 34

I have a set of the Genelex gold lion kt77's I've tried them in two amps, both push pull, and find they are inferior to the similar gold lion 300b by a significant factor. 

I find the top end to be rather harsh and not very extended. I'm using a three way horn system so its rather reveling in the top end. The basic Messa branded el34 is better in many ways, IMO, not perfect but for cheep tubes they work rather good over all. 

Now maybe the kt77 are not broken in but I don't think they take that long and I've tried them in two amps now with the same result. I really wished they were better as I have a set of the Gold Lion 300b variants and they are stellar. 

I'm now on the fence if I try the Gold Lion 2A3's in my new amps.

I have a Leben CS600.
I believe the KT 77s would be an option.
I would favor a smooth top end

@mpomerantz a jeffsplace review replacing the stock electro harmonix EL34s with Sophia Electric EL34 and KT88s, on the Leben 600X. Gives an idea of what room for improvement might exist over the stock EH for your type amp.  Other member feedback comments below the article too, fwiw. https://jeffsplace.positive-feedback.com/leben-cs600-cs600x-tube-rolling-with-sophia-electric-vs-ele...

RAM tubes :-) Roger Modjeski but still going strong w super matching and testing, $45 gets you a killer valve

in my experience

ranked by overall sq (including midrange beauty) - we are talking old stock tubes here, not the new/modern day russian/czech/chinese tubes

best
gold lion gec genalex kt77 (uk made)

close/next best
mullard/amperex el34 (uk or dutch made)
matsushita el34 (seam top) - (japan made using mullard tooling)

close/next best
svetlana sed winged c - russian old stock st petersburg plant
tesla yugo el34 brown base yellow print

not as close, next best
philips/national east german thin bottle dimple top el34
yugo ei fat bottle 6ca7

amps i have/have had in which i developed this ranking - vac pa90c, air tight atm-3, primaluna hp prem dialogue, linear tube audio zotl40 reference, marantz 8b, cj prem 11a xs