Power Tube Life

Hi all,

I have provided a link to an article published in 2005 by David Gillespie. He advocates the inclusion of screen resistors to improve stability and reduce arcing. He also advocates delaying B+ application.

Let me know what you think.

Thanks,

Dan

Gillespie Article

After trying out one of my modified Mark II (with greatly increased power supply reservoir storage) in triode mode, I left the added resistors in there and used them as screen grid resistors as suggested by Gillespie and others, although I had had zero problems with output tubes arcing. I can't detect any deterioration in performance by doing so; if there is a safety margin thus introduced, I'd have to say it comes for no cost (well, for a few cents that the resistors cost) and for very little effort.

The other modified Mark II has not received the screen grid resistors. But as mentioned, I've not had any tube arcing in either one.

He also advocates delaying B+ application.

The way i get the B+ delay in the Dynaco MK3s is to put a swetch in the B+ center tap,this is a ezy way to get the heaters on an then add the B+.
Thanks for the post

Thanks Bob for the site