[Boatanchors] AB1 Modulator

[Barrie Smith]

I'm looking for information, schematics or ideas on AB1 modulators using larger triode tubes.

I built a class AB1 modulator using 304TLs quite a few years ago from a schematic I no longer have.

There's very little information on AB1 modulation in the several old handbooks I have.  There is considerable information on class B.

I had individual bias control, with separate filament transformers, in the 304TL modulator, but I don't remember how it was done.  Perhaps with a rheostat in each filament center tap?

Any help appreciated!

73, Barrie, W7ALW