Single tube, Single ended, 20W, impossible?

[MelB]

My that's some coincidence. I just built a GM-70 amp. Insanely nice tube. And very cheap. That's a hammond 18v 5 amp trans for it's filament supply. Ya 60 watts for the filament. It's just like a light bulb. This is my first iteration. Just using a Hammond 300-0-300 transformer gives me 810v on the plate. The power supply is designed for max 1200v though. I will switch in a 400-0-400v Hammond after some more testing. Should get about 1050v on the plate. I'm stopping there.

[Wavebourn]

Originally Posted by MelB

My that's some coincidence. I just built a GM-70 amp. Insanely nice tube. And very cheap. That's a hammond 18v 5 amp trans for it's filament supply. Ya 60 watts for the filament. It's just like a light bulb. This is my first iteration. Just using a Hammond 300-0-300 transformer gives me 810v on the plate. The power supply is designed for max 1200v though. I will switch in a 400-0-400v Hammond after some more testing. Should get about 1050v on the plate. I'm stopping there.

I would put a mirror between tube and transformer. Too hot and too close.

[Adipocere]

Originally Posted by Wavebourn

I would put a mirror between tube and transformer. Too hot and too close.

No no no! That will just reflect the heat back to the tube's plate! The endbell won't be hurt by a little heat.

[MelB]

It's a lot further away than it looks in the other picture. It is not a problem at all.

[Wavebourn]

Originally Posted by Adipocere

No no no! That will just reflect the heat back to the tube's plate! The endbell won't be hurt by a little heat.

It depends on how much is "Little". And how "cheap" is transformer for such an amp.

[Wavebourn]

Originally Posted by MelB

It's a lot further away than it looks in the other picture. It is not a problem at all.

Sure, I see now how far it is, how anode is oriented, and how shiny is the bell itself.