[ETO_Alpha] EBS on the 77 amps

[Randy Starace]

HI Guys,   I was looking at the input circuitry on the 77 and it is at best a shunt circuit,  I know from a design point of view we would ideally like more then a 180* swing on our input signal.  I am sure the characteristics of the shunt circuit present that to the tubes.   I think the fact that the drive requirements on the tubes and the era that they designed the amp have much to do with that circuit.  Most of the exciters used when the amp was introduced had PI and PI L output networks that were tunable to match the amps impedance.  Together with just needing 10 to 30 watts drive for 1500 +++ output,  ETO felt that a PI input was necessary.  On the other hand,  now a days having an ATU built in to our SS exciters would more then make up for miss matches encountered with any amp.   I also think that it would not be hard to change the input design on the 77 to an L network with just some wiring changes and alignments.
Randy Starace
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