EL 34 vs. KT 88 ---- What's the difference?


Can someone please tell me or be able to describe the sonic differences in the use of each of these tubes?

Is one tube better than the other...or does one tube provide more warmth and tube-like qualities than the other?

Does anyone know why a tube amp designer would select one over the other?

Thanks.
128x128gerryn
Is there anyone who has an amp that is made to handle both EL34 and KT88 and prefers the EL34 generally, that is if you had to make a choice you would stick with EL34 over using the KT88. I think one of my amps (Music Reference RM9 SE) was built around the Siemens EL34 tube, but I still think it sounds better with the Genelex KT88 reissues.
Pubul57--My Dynaco mk iiis take both el34s and kt88s, but they're powering only the midrange/tweeter cabinets of my VR4 HSEs. Also, my kt88s are EH and the 34s are the winged c variety. That said, despite the fact that the fat bottle kt88s are the most pleasing to look at (not that anyone cares about that!), I find myself going back to the el34s. The difference, to my ears, is slight, and I doubt most could hear the difference if they weren't trying to hear it. But there is something special about the el34 midrange, at least in my system--not just more of it, but a different sonic character. Liquid is a word often used, and that gets at it.
PrimaLuna amps will accept EL34 or KT88. I tried both driving my Klipsch RF7's and agree with Jeffreybehr on the sound difference between the two.
My Granite monoblocks took both the KT88 and EL34. I could never get them to sound right with the EL34, and am pretty sure it was an issue of bias, though I didn't pursue it too much.

My Jadis DA30 and DA60 integrateds can also use either, and I strongly prefer the EL34 in both of them, provided the right driver tubes are used to address the loss in low frequencies that occurs otherwise. In a nutshell, the EL34 really walks away from the KT88 in the midrange, giving both amps a far more musical and natural presentation.
I agree with most of the above comments, having owned and used EL34, 300B push pull, 300B SET, and heard a lot of KT88.

I love the sound of EL34 in Ultralinear mode, which gives both sweetness and "pace" or "robustness" or whatever you want to call it. With just about any dynamic speaker, that's a heavenly combination. Note that 300B tubes, which are also glorious, are far more expensive, and ergo more difficult to experiment with.

Often the KT88 has been used in stacked configurations to provide high power tube amplification. How the tradeoff between power and tube "sweetness" comes off is very subjective. Well implemented, they can both be great.

I am curious if anyone has tried to use KT88 ultralinear amps with low sensitivity exotics, such as Soundlabs? Any user experiences?