KT77 Tubes or 6CA7? | Stereophile.com

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March 31, 2008 - 4:20pm

#1

linden518

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KT77 Tubes or 6CA7?

I'm not entirely satisfied with the 6L6GC tubes in the Leben (using Winged Cs now; good balance but sounds recessed) or the EL34s (again, Winged Cs: way too forward, especially in treble & mids, too mid-range-y & typically "tube-y" & extroverted in sound)

I've been asking around and I've been told that KT77s might fill the gap nicely between the 6L6GC & EL34 sound. I was going to get a quad of JJ KT77s, which seem to get raves from their users, but I received one word of caution from a very knowledgeable tube guy, that JJ KT77s have build quality problems & reliability issues. Is this true? Has anyone here used JJ KT77s?

Other tubes I might try are 6CA7 EH. Any comments/suggestions will be appreciated, as usual.

March 31, 2008 - 6:31pm

#2

KBK

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Re: KT77 Tubes or 6CA7?

the original Mullards were frighteningly good. (6CA7)

I've not heard much about the new 'copy' but it might be fine. Tubes are microphonically sensitive, by their very nature, just like all electronics, but only moreso.

Only if the original microphonics and the design parameters that were used to deal with those issues, in the new copies..if those things were added in, then the new tubes would sound quite similar to the old Mullards, which were great.

Also, consider the parameters that the amp was specifically designed around. Which exact tube type? those tend to sound best, as the amp might work with various tubes, like car with various tires, but there is only one specific tube, or tire, that works best, with the lowest amount of issues. What problems? Distortion under load.