new production KT88 and 6550

[phsyconoodler]

Are they the same essentially?they sure seem to be except for the glass.

Any thoughts from the tube gurus?

[diagrammatiks]

i was under the impression that there was a lot in common between those two tubes anyway.

[Stonecutter]

I've only ever used either SED or EH 6550's or KT88's for the most part. I've noticed a consistent difference in sound between the two EH types. Never got a real good test between the SED's before they skyrocketed the price, but I did also notice similar characteristics to their EH counterparts.

For what it's worth...

[Roe]

not the same. 88s will handle higher screens voltage

[phsyconoodler]

Good info,but all things considered at the same voltage and bias they seem to sound the same.I have to use KT88's in repairs where I work in place of 6550's cause our parent company doesn't stock 6550's anymore and they send us KT88's and say "use 'em".

[Roe]

88s can be substituted for 6550s, but not the other way around if the screen voltage is high

[phsyconoodler]

Thanks!

[Rod]

To my ears kt88's sound different than 6550's... In a more musical way

[drbob1]

I've used them in the same circuit (GT Dual 75) and I'd describe the 6550 as a really big 6L6 and the KT88 as a really big EL34-they break up a little more subtly and have perhaps just a bit more of that British midrange klang. I do prefer the sound of the KT88s by a small margin (have em in my Sano accordian amp and my Sound City PA200). I'm kind of partial to the Golden Lion reissues, expensive but they sound good and they should last forever...

[Roe]

also, 88s often handle large bias splitters than 6550s. I'd avoid values higher than 150k though