In the early 1970's there was a National Semiconductors app note on a
modulated switching regulator, supposedly for use in powewring a high
efficiency solid state HF linear. The idea was to vary the supply voltage in
sympathy with the envelope of the modulation, so maintaining efficiency.
Does anyone know of any work done on modulating the plate supply of a tube
amp in sympathy with the envelope of the signal? When you consider that a
pair of 6146's were rated for 100 watts carrier, 100% modulated, which is
400 watts PEP in AM service, then some sort of plate voltage variation with
modulation would appear to give the posssibility of 400 watts PEP of SSB.
You might even get 1kW linear out of a pair of 4CX250Bs that way!
And no, this is NOT a G2DAF.
Could we see modulation transformers coming back into fashion?
73
Peter G3RZP
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