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KT-77 vs. KT-66

As I've had my QS Mono 60s, I've tried a variety of tubes. I have sold off my KT 150s, and use KT-88s from time to time, but what I really love are KT77's.

I'm thinking of getting some KT66s, thinking that lower powered tubes are better (to my ears) matches for my system. I just don't know what the KT-66's sound like. 

Question: If you have compared KT77 and KT66 tubes, what would you say the sonic, audible characters of each are? Is there a difference you can hear? What does the KT66 sound like -- to you?

128x128hilde45
yogiboy's avatar
yogiboy
5,769 posts
 

 

@bojack

Those are different amps!

M60 Mono Amplifier

hilde45's avatar
hilde45 OP
5,114 posts
 

Found my old emails.

Mike Sanders said about my (later) Mono 60's

"They should be able to use KT66 or 6L6 tubes.
The Sixty watt amps have a plate voltage of 500 volts."

He also said,

"EL34s and 6CA7s should not be used in the Sixty watt amp."

So, that's the word from the maker regarding my amps.

jond's avatar
jond
5,911 posts
 

@hilde45 I am still a bit baffled by this he says not to use EL34s but you can use KT66 and 6L6 but also KT88s and KT150s?

newbee
4,777 posts
 

Jond, FWIW, it's probably the the plate difference between the two amps which determine which tubes you can use. I don't know, but I'd risk a bet that the amp which can use EL34's has a plate voltage of 450 volts. The 500 volt unit would probably stress the EL 34's and cause them to fail. FWIW KT66's, 6L6gc' s and other 6l6 variants are not all equal, electrically speaking, so I wouldn't recommend that you use them without making sure that your amp would be appropriate for a specific tube. 

hilde45's avatar
hilde45 OP
5,114 posts
 

I think it's a plate voltage thing. I'm not an engineer and just follow instructions!

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