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

First, the power outputs of the 2 vary significantly. In pentode/ultralinear/beam-tetrode mode, for which both were designed, a pair of '88s is capable of as much as 100 Watts, altho perhaps 70 is more common, while the '34's typical max. per pair is around 50*, with around 40 being more common.

On sound quality, the consensus seems to be that the '34 has more lushness or richness in the midrange than almost any other mid- to hi-power output tube while being a little soft at the frequency extremes. The '88 (and its very close cousin the 6550) is more balanced across the frequency band, exhibiting more-extended and -controlled bass and better-quality treble than the '34 while lacking the '34's (euphonic?) midrange richness. These differences probably can be swamped by the extremes of different brands of the 2; the above is average or typical.

* Conrad-johnson is currently getting 60 Watts per pair of '34s in their MV60, but that has much-larger-than-average (for '34s) output transformers.
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hello, good question here sounds simple, but i don't think it is. I think it really depends on the speaker. I think most people would say the EL34 gives you more of the tube thing, while kt88 or 6550s give more control and better bass. Back to the speaker interface...for example, I have Khorns and they just LOVE a good EL34 amp. To wit I have tried a fair amount of VTL amps on them...the IT85, MB125,ST85 all three sound great, tried their upper end amps, the ST150, MB Sig 185 and even the MB250 all more money......preferred the the smaller amps with the EL34s.

Now try them all on a very good dynamic speaker, you might get very different results...I also have a Mac 275 Mk4...great amp uses 6550s,sounds very nice on the Khorns, but just shines on my B&Ws...again a dynamic speaker.

So thats what I have found, amp/speaker interface is key...but so is the rest of the system...to avoid going nuts with this hobby, I have a saying....if it sounds good ....buy it.

My two-cents worth. I agree with previous comments. Personally, I appreciate the 34s more. Having once owned a Sonic Frontiers SF80 amp outfitted with 88s, I was amazed at the "robustness" of the sound. This being said, once I substituted 34s, I simply liked the sound more. More like music to me.

Of course, one can always, if prospective amp allows, switch out the two tube types--kinda gives one two amps.

BTW, I still own a CJ MV45a amp--with EL34 tubes! However, my "super" system consists of Atma-sphere MA1s.