IIRC, RCA used a magnetic amplifier in the AFC loop of their BTE-10C FM Exciter, but I don't remember why it was chosen over a more conventional design. Mark On 2/14/06, N0JAA at aol.com <N0JAA at aol.com> wrote: > > > > Has anyone here ever used magnetic amplifiers? If so, what did/do > you think > about them? > >