Heat question

[Bernardduur]

Hey all!

I have little experience in the amp building business; just finished my version of a Liverpool preamp with the Express poweramp; she sounds too clean for me (check the other post) but what I noticed when I switched her on was the heat that is building up on the power tubes..... as I never played such an amp, is it normal that the power tubes get really hot (smelling hot) without running red? Approx 470V goes through em biased at 19W

I'm using the EL34's that came with the amp; I haven't tested em

[geetarpicker]

An original Express runs closer to 415-420v B+ (when biased at around 45ma) so it sounds like your plate voltage might be too high.

[Ron Worley]

Based on what I've read and been told, 20W is max dissapation- you're burning the tubes up.

70% of max dissapation has been suggested, so that would be 14W.

Depending on your plate voltage hope fully that will get you around the 42-45Ma value suggested by Geetarpicker and others....

Ron

[Bernardduur]

Based on what I've read and been told, 20W is max dissapation- you're burning the tubes up.

70% of max dissapation has been suggested, so that would be 14W.

Depending on your plate voltage hope fully that will get you around the 42-45Ma value suggested by Geetarpicker and others....

Ron

Thx!

An original Express runs closer to 415-420v B+ (when biased at around 45ma) so it sounds like your plate voltage might be too high.

I know; I made a post on it on another part of this forum