Globe Champ

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WBear2GCR:

I started on a Glub Chumpeon 350... Got part way through. It's still awaiting more attention.

Here's my take.

Remove the Couplates.
Throw in trash.
Remove the bandpass filter (the part with the choke).

Build up a standard speech amp circuit.

To drive the 811a tube, imho, you want to expect to run into AB2.
That means you will draw grid current.

The good thing is that the 811 can be driven quite well with a 6W4, or for more snot
a 6V6. A pair in PP as a driver is more than overkill.

Personally I'd not use an interstage transformer, and would opt for a cathode follower driver.
It's pretty simple. The good part is that the old transformer will work fine as a choke sitting
in the cathode of the driver tube. This assumes that you have something to create the + & -
phase drive.

In reality, one can make a circuit with NO choke in the cathode, and no resistor in the cathode,
the driver cathode goes to the grid directly! :D

Another option is to use the IT to make the phase splitter, and use that to drive the grids of
the cathode followers, then all you need to do is to get the required voltage swing at the
follower that drives the 811 grids.

With about 900volts on the 811, you'll have a zero bias set up - no bias supply required.

                    _-_-bear

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