KT-88 in Conrad Johnson Premier 11a

I've used Chinese KT88s and Ei KT90s in a couple Eleven-As and they bias just finely. Never heard of an amp designed for 6550s that wouldn't bias KT88s...but what do I know? :-)
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I use the svelenta KT88s in my preimier 12s bias adjustment is pretty close to the 6550s,you can use them no problem.

I used a variety of KT-88 and KT-90 in my Premier 11a and Premier 12's. They were all wonderful, so it is very much a matter of taste.

This is the only line of amps in my experience where I ended up preferring 6550 to KT88 or KT90. Usually I prefer the slight touch of ripeness added by these latter tubes. But CJ gear already sounds sweet with 6550's and the KT88 and KT90 were a little over the top for me by comparison.

But I don't think you can go wrong try ing it out, its a huge part of the fun of the hobby.

Art

Thanks everyone! I read some discussion saying KT88 needs to be biased differently on some amps as it works best in a slightly different current flow.

Anyway I am really tempted to try KT88... Artmaltman, which brands of KT88 did you try on your 11a and how would you compare them?

I wish I can try GEC if I had the money. =p I am choosing from Svetlana, Electro-Harmonic, or SED. I found on some tubes store websites that SED is re-branded Svetlana... but SED costs more. Anyone knows the story behind this?

Thanks!
Andy

Hi, Hklai:

Svetlana was a venerable tube manufacturer with a plant in St. Petersburg, Russia. Several years ago, a company in the USA named Sovtek purchased sole rights to the brand name
"Svetlana," as well as other famous brand names, such as Tung-Sol and Mullard. So now Sovtek makes and markets tubes labeled Svetlana which are considered my some to be inferior. Meanwhile, the original (real) Svetlana makes tubes labeled SED-C with a winged 'C' logo, and some older production SED-C tubes carry the name Svetlana on the boxes. Sovtek markets some tubes that are said to be musical, including the Electro-Harmonix KT-88. Go to the above link to see a photo of a real Svetlana SED-C KT-88.
Best wishes,
Jay

Correction: New Sensor markets Sovtek, Electro Harmonix, Tung-Sol, Mullard etc. Apologies for the error...

Thanks Jburidan. Yes I used the older Svetlana KT-88, which would now be SED brand. The KT-90's were EI from Yugoslavia. I bought these all from Kevin Deal of Upscale Audio, if I recall correctly.
Art

Thanks Jay and Art!!

I'm really curious to know how the NOS Genalex KT88 sounds... and wonder if they can really live up to their price.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5766639003&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

Art, did you happen to try Electro-Harmonix as well? I wonder how it compares to the SED... I will pick either one of them...

Thanks,
Andy

HKLAI,
The EH KT88 will sound more dynamic, tighter more powerful bass, a bit brighter top & extension.

The Svetlana KT88 will have a slightly romanticized midrange, with a burnished sound, more tubeish sounding, the EH sounding less tubeish. The highs have a bit of cloudy coloration.

It amounts to a matter of taste and the gear it is in. If the Premier 11a sounds lush with the stock Svetlana 6550 (which are leaner & more analytical than the Svet KT88), you might prefer the EH KT88.

By the way, I had both old winged C Svets, and didn't hear a difference between the New Sensor Svetlana and the winged C, and they looked identical in construction.

Hi, Hklai:

I believe the NOS Genalex KT88 is the best ever, but almost impossible to find. Beware of fakes on e-bay.
Best wishes,
Jay