High Power 805 Triode based amplifier

[BlackUnikorn]

Anyone familiar with this transmitting tube? spec sheets can be found at frank's electron tube database. I am thinking about building a PP class AB leaning towards class B high powered amplifier based on this tube. Manufacturer datasheet suggests 1250 Volts at the plate into a 6.7K tranny for 320 watts power output! The only problem seems to be driving requirements 220 volts p-p grid and a lot of input current to drive the grid (6.5 watts). Output tranny would be a 6.0K Lundahl using the 250 watt connection. Plate voltage would be lower than 1250, maybe around 1100V to lower the max. power output. Load line looks promising, but the tubes would have to be run almost in class B, which might affect sound because of crossover distortion.

Would a 6BX7 running at high voltage (500V), choke loaded (80-100Henries) directly connected to the grids provide enough swing and power to drive the grids? What other tubes are suitable for a driver? Would EL-84, 6V6, 7119, SV-83, or even a 6L6 or EL-34 triode connected work?

[Eli Duttman]

Here's a link to a mu follower for driving the SV572-3.
http://www.svetlana.com/graphics/TB/No.27fig.jpg

If that design doesn't have enough drive, scale it up to use a 12AT7 and an EL34.

[BlackUnikorn]

Thanks for the link. So would I feed two Mu follower stages with the outputs from a phase splitter?

[Eli Duttman]

So would I feed two Mu follower stages with the outputs from a phase splitter?

That would get the job done.