Can the Herbert safely run with KT88 and 6550 ?

[sdhnc123]

Can the Herbert safely run with KT88 or 6550 without overheating?
My Herbert is "Mk2".
I have a few medium sized fans that I could use to keep it cool. The Herbert gets very hot now and it is running 4xEL34 and 2x6L6.

 

[spguitar]

I'm running KT88s just fine. It does get pretty hot though.

 

[Jens Kruse]

We do NOT recommend running those big tubes as the transformers are NOT designed to accomodate the currents these tube types need to draw. These are very inefficient tubes and get mighty hot. It might work for a while, but long term damage is the big risk. Of course, the decision is up to you.
Peter designs his amps for EL34 tubes, so any tube type similar to that size is technically ok to be used.

Jens Kruse

 

[sdhnc123]

Thanks. I will avoid KT88 and 6550.

 

[Peter Diezel]

Good boy