EL34 Amp Running KT66, Safe ?

[istari knight]

Hi all, its a newbie question im afraid!

I recently bought a tube amp : A.V.C EL34 also known as Vincent T.A.C-88. Its an EL34 design but the previous owner has fitted a quad of KT66, I really need to know if this is a safe thing to do as although it sounds fine the mains transformer runs too hot to touch which got me wondering.

Safety aside, is there any sonic benifit to using KT66 over EL34 ? Especially in an circuit not designed for them

Thankyou for any input.

 

[vinylkid58]

I recently bought a tube amp : A.V.C EL34 also known as Vincent T.A.C-88. Its an EL34 design but the previous owner has fitted a quad of KT66, I really need to know if this is a safe thing to do as although it sounds fine the mains transformer runs too hot to touch which got me wondering.

The extra heater current that the KT66's draw may be to blame for this. Or, the trans may be spec'd a little on the "light" side regardless.

Safety aside, is there any sonic benifit to using KT66 over EL34 ? Especially in an circuit not designed for them

Here's you chance to roll in some EL34's and find out.😉

jeff

 

[woodturner-fran]

Heater current is less than on an EL34 so that shouldn't be a problem. AFAIK, you can run a higher bias with the KT66 - is the amp fixed or auto bias?


Fran

 

[vinylkid58]

Hey you're right. I guess I was thinking of 6L6GC vs KT66.

jeff

 

[istari knight]

Thanks for the input 🙂

Its a fixed bias amplifier (Gaffer's Valve Bias Page) The seller assured me that he had correctly biased them just before sending it....I just took his word & havent checked....Probably should!


Thanks.