|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
99.248.236.101
I have three kt90 tubes,the fourth one in the quad shorted out. I am now looking for another to make up the quad. Problem is I am not aware of how to tell the difference between types, does it matter?
Bob
PS I am 81 this year, and still love my music.
Follow Ups:
The KT90 II are very nice, but I do think the III are just a tad better "IF" you can find the early production ones. I have a quad running very nicely and another matched quad (Upscale Audio) still in their boxes. Sometimes I think about letting them go, but I've had a hard time pulling the trigger.
Thank you for the information. I hope the picture could identify them.
The one that shorted blue to of the caps in the auto bias circuit, which I replaced. The amp is an Art Audio concerto 11 which I like very much.Now using EH kt90 from Jim Mcshane.
Bob
Those are type III, the "wings" on the plate are what to look for. I wish I has one to send you, but I don't.
BE CAREFUL!! All but the earliest production type IIIs had misaligned screens and are prone to both red plating at about 50% of rated dissipation and they'll have higher THD to boot.
Thanks Jim, appreciate your help. Now all I have to do is find one.
I ran them for a while before the short and did not notice any red plating.
Bob
Thanks to the Wayback Machine Manley's KT-90 page is still available. The link is below.When you determine what you have please let us know. One of us might be able to help.
Edits: 08/06/14
Thanks for the link Jim! Been trying to find that for a while. Best way to determine what type of EI KT90 you have.
IMO the EI KT90 is still the best KT88/6550/KT90 ever made, although I have not heard the Black plate Tung Sol's. Sorry guys, but the current Genelex and EH tubes do not compare.
Bob, these tubes are legendary for their longevity. The three good ones are very likely still strong. Try to determine which type you have and find a fourth one. The type 2 are the easiest to identify with all the weld marks on the plates. Type 1 are cooler biasing so probably won't work as well with the others in a push/pull amp. A good type 3 should work with a good type 2, although it would be better to have 4 the same type.
Can you post a picture of the ones you have?
Hi Mendel,
I agree the KT-90 (when properly made - pre Balkans NATO intervention tubes) are the best there is. I think the current Genalex is quite close, but nothing will touch an Ei KT-90. It's simply a GREAT tube!!
IIRC the desireable typeII had welded.plates. you would still need to test to test existing tubes to match, however ,depending on amp biaising.
Good Yugo Ei KT90s are really hard to source. Just spring for a new quad of tubes as the others are probably going to follow suit. The Genelex reissue KT88s are nice. The next failure could take out your amp.
We all miss the Ei KT-90s, but the current crop of EH are really quite good, easy to source, and at about fifty bucks a pop they're something of a deal.
WW
"A man need merely light the filaments of his receiving set and the world's greatest artists will perform for him." Alfred N. Goldsmith, RCA, 1922
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: