Broadband tube driver circuit needed
 

Want to have broadband (7-28 Mhz) 1 Watt (50 Ohms) class A solid state
amplifier driving grid of 6L6 tube to about 2 or 3 mA grid current, tube is
biased to about -65 Volts for class C operation with 550 Volts on the plate.
I don't want to have any tuned circuits in the 6L6 grid if I can avoid it.
As of now, the 6L6 has a 6CL6 driver feeding tuned grid circuit, easily gets
2-3 mA.
My goal is to eliminate the driver tube and the tuned grid circuit.

Anyone have knowledge of toroid(s) that might be required, turns ratio,
material, etc.?
Do I need a more driving power ? Probably could get 2 Watts out of my driver
circuit if need be.
thanks
Bob
kb8tl at yahoo dot com

Bob P wrote:
Want to have broadband (7-28 Mhz) 1 Watt (50 Ohms) class A solid state
amplifier driving grid of 6L6 tube to about 2 or 3 mA grid current, tube is
biased to about -65 Volts for class C operation with 550 Volts on the plate.
I don't want to have any tuned circuits in the 6L6 grid if I can avoid it.
As of now, the 6L6 has a 6CL6 driver feeding tuned grid circuit, easily gets
2-3 mA.
My goal is to eliminate the driver tube and the tuned grid circuit.

I think you'll find 1 watt is optimistic for _output_ power on a 6L6
at 28 MHz.

So, why are you trying to do this, rather than use a tube with a more
reasonable Miller capacitance for a final?

How is the existing driver biased?

Anyone have knowledge of toroid(s) that might be required, turns ratio,
material, etc.?
Do I need a more driving power ? Probably could get 2 Watts out of my driver
circuit if need be.

The transformer is easy in theory, because it's not tuned. In practice
it might be a problem since the 6L6 input impedance is going to vary wildly
at those frequencies.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."