811A SE?

[antiquekid3]

Hey guys,

It seems to me 811As are fairly inexpensive power tubes. Does anyone have any recommendations for a SE design? I'm hoping to avoid expensive transformers, and the fewer tubes the better.

I have a power transformer that I'd like to use if possible. Here are the specs:
Stancor P-8339
Pri: 117V 60Hz
Secondaries: 325-0-325V @ 255mA DC
5V @ 3A
12.6V CT @ 5.25A

It seems as though it would be rather perfect for some 811As...what do ya'll think? ~450V B+, plenty of filament current, etc.

Or does anyone have another better suggestion than the 811As so I can use this big hunk of iron?

Kyle

[soundbrigade]

I eyed this tube up a while ago. It's a powerful tube that could be a good compromise if 300B is to exclusive and 845 too powerful.
Howver I am so confused when it comes to 811, as there are the original tubes with top anode connector and the special made audio tubes like 811-3, 811-10, not to mention the closely related 572. Most of those came from Svetlana and are now no longer in production (I've heard).

I have some schematics somewhere else (on a disconnected HDD) and will take some weeks before I have scheduled a reconnection, but google on the SV811 and SV572. There are some designs, but remember that the 811/572 needs current on the grid (positive bias voltage) which also means demands on a powerful driver. I've seen simpler designs with 6BM8 and EL34, but expect some problems.
A balanced designed SV572 can give you LOTS of Watts!

[kheper]

http://www.bonavolta.ch/hobby/en/audio/sv811.htm

Most of these schematics use a volt amp -> cathode follower driver stage, and they use an output transformer with a 5 - 6K impedance.

[jetpack]

If anyone is still interested in this, I've come by an 811 SE schematic driven by a WE310b and an 807. From what I understand, a 6C6 is a cheap sub for the 310. PM me and I can email it. Cheers.

[DeathRex]

Here's the schematic I used.