what're the differences between KT66's KT88's and KT77's.

I understand that the 66 and 88 are very large "powerhouse tubes"
and the 77 is a more EL-34 with more low end/Raunchy 6L6.

but whats the big difference between the KT66 and KT88.
do they both give off about 50W or is that only the KT66?
just wondering, concidering new tubes in my single rectifier this summer.
If you don't talk to your kids about GAS, who will?
If I remember correctly, the KT88 (or 66's, can't remember) are the same thing as a 6550 tube? I had some 6550's in a JCM 800 combo I used to own. To say the least, they had some incredibly massive low end, and kind of a "glassier" tone to them than an EL34. Rugged as hell too, so they don't break up as easily as EL34's. I find that they sounded nice with an OD pedal in front of the amp as it ate up some of the lows, but the low end was a bit much otherwise IMO. I switched back to EL34's before I sold that amp.

I hear KT77's are awesome though. Like an EL34, but a bit beefier sounding.
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wikipedia says:
A number of different KT tubes were later marketed by M-OV. Some, but not all, were versions of existing American beam tetrode tubes or European power pentodes, such as the KT66 (6L6), KT77 (EL34) and KT63 (6V6)

the KT88 has similar ratings to the American 6550
which is basically a 6L6 with higher output and better stability(less breakup)
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Last edited by justinb904 at Mar 11, 2009,
hmm... im not sure what to say to this. i have a single rectifier, all stock tubes. looking for something to maybe lively it up a bit.
If you don't talk to your kids about GAS, who will?
If they're stock MESA tubes, you should definitely upgrade them! Try some Tung-sol 12Ax7's for your pre-amp tubes, not sure what I'd recommend for replacement 6L6's, but I have the tung-sol's in the pre-amp of my F-50 head, and I love them. Plenty of clarity, liveliness, and definition.
aren't tong-sol's cheap russion tubes, similar to sovtek?
If you don't talk to your kids about GAS, who will?
i see, i've always liked JJ and Ruby tubes. how would a JJ retube with KT77's affect my sound of the stock mesa?
If you don't talk to your kids about GAS, who will?