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Thanks very much for sharing that schematic! Even with the resistive loading it looked like the grid given PA of heathkit transceiver was doing about 16 dB gain. I wasn’t brave enough to try it higher than 20 m
Do you have any advice on whether we should try resistive loading higher impedance than 2500 ohms???
By using the tuned plate circuit of the 6cl6 driver, I guess we are already dealing with any grid capacitance in the process
I never did anything like this before (since I home brewed a 3x 811 a amplifier in high school ) it’s pretty cool for me to get back to this
On Nov 10, 2019, at 11:59, ajparent1/KB1GMX <kb1gmx@...
The attached image was the solution of the 60 and 70s for hams (and CBers)
for 100W amp. it was cheap 10-13DB of gain. Alas sweep tubes got expensive
as people burnt them all up pushing those. There were generations of them with
up to 6 (SIX!) for a KW input peak. Not all were clean.
Some did grid driven and they worked save for over drive the grids and the
tubes protest by going away. At 25$ each that is a bad thing.
For laughs a decade ago I took a 4CX250 and ran it grounded grid like that
and it was good for about 80W (on 6M) out in a simple circuit without forced
air cooling. The tube with screen bias (its a ceramic metal power tetrode)
added did an easy 300w out at 2000V (a very lethal power supply). The
amp was terminally simple save for a typical tube amp tapped load coil
Pi network for multi-bands. There are a long list of tubes that can can
be used for that that..