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In the Forum: Audio Discussions
In the Thread: How to get a LOT of SET power.

Post Subject: Missing miliampersPosted by N-set on: 4/18/2011

Paul, 6E5P may strech very much, but maybe just enough to close the gap.
In such a racing car there is a little margin, it's not a usual 10W+ design.
Biased at -3.5V 6E5P will produce +40Vmax on the grid, driver driven to the limit
The grid will eat 50mA@200V (the endpoint of the proposed loadlines)
according to the datasheets, 40mA@400V. The 6E5P is on 40mA...
Anyone has a GU81M spice model?

I've been somehow missing some current, which I've finally found: the screen!
According to the data eats up to 300mA at 0V bias.
The 20k resistor is an idiocy, the screen needs a dedicated supply, IMHO, it's a 120Wmax anode!
I'd also be happy to find somewhere take few negative volts to be able to adjust the
GU81M bias without changing the driver's current.

2 signal tubes, very simple signal topology...and 6 different supplies!!!What can one do?
Physics...
The VR's are screened from the load as I'm affraid the G2 current impulses
may extinguish the them. The last cap should be the biggest possible, G2 acts as an anode
and conducts all the impulses!

I've been thinking about paralled 6c33c and I will not go into that. To get 150W A1 how many 6c33c's
one needs? 10? this is over 400W of the heater power alone, 1kW with anodes max.
Now go ahead implement, maintain and
stabilize that mastodont! I think this pig won't fly, the tubes will drift thermally,
unless the chassis occupies 2/3 of the room surface. One-two big tubes are easier to
implement, eventhough they sit at few kV and need 39656 supplies....and much more elegant.

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