KT66s in my Mesa?

[Sardocasm]

I've been wanting a different sound from my Heartbreaker and don't like El34s in it and am tired of 6L6s so I was wondering if it would be safe to do so since it's a direct replacement or would it cause problems/not sound good since Mesa's are set bias?

 

[dennq45]

I have two Tung-Sol KT 66's on Flea Bay. Check em out.

 

[CaughtLikeFire]

I've been wanting a different sound from my Heartbreaker and don't like El34s in it and am tired of 6L6s so I was wondering if it would be safe to do so since it's a direct replacement or would it cause problems/not sound good since Mesa's are set bias?

the russian Kt66s (Groove Tubes sold them as the KT66HP) are no longer being made so there are only one or two chinese KT66s to pick from - thats one downside. You need to deal with a tube vendor that will select KT66s that fall within the Mesa range - thats a given. You can't just buy any Kt66 off the web.

You also have to deal with fitment issues - the size of the glass varies between brands and even varies within batches of the smae brand. you may need to take measurements to make it fit. KT66s are big tubes.

And finally, if you dislike the tone of your amp to the point where you're ready to sell, even $1000 worth of the best New Old Stock tubes wouldn't make the amp good enough for you. Tubes fine-tune and make minor alterations - they can't and won't transform one amp into another or transform a bad amp into a good one :wink:

 

[dmt]

I have Sovtek KT66 tubes in my Boogie, and they sound killer. Unfortunatly I need to retube them soon. Its been about a year an a half and they have lost their blueish glow. Its too bad that they dont sell Russina KT66's, i rather like them. Whats something comprable?

 

[Elpelotero]

can someone describe the tone of KT66's compared to the stock Mesa tubes, be they str420 or str440? thanks

 

[joey_truelove]

The KT-66 is supposed to be a bottom heavy and rounded thingy, a bit like the 5881. The KT-66 was used in early Marshall amps and can be found in the Jimi Hendrix stack.

Just a note of information: The original KT-66 was designed for 25W output, like the 6L6GB and the 5881, and a rather high current draw. That makes NOS KT-66 out of the question.
As with Sovtek: the shape and printing on the valve seems in most cases be for fooling the eye rather than a different tonal offering. Their so called KT-66 sounds a lot like their 6L6WXT+.
Great review: http://www.thetubestore.com/6l6templeton.html