[AMPS] Tuned chokes

[Peter Chadwick]

Following the comments on tuned choke inputs, I agree with Bob and Rich: I
use tuned choke inputs on my linear with great success. But you do need a
suitably large cap for tuning - there is a fair amount of circulating
current. I have some 0.1mFd, 1 KV paper jobs about 50 years old and abt 6
inches high by 4 wide by 2 deep with big insulators. I figure that size is a
good indication of heat dissipating capability, while the measured tan delta
is pretty low. If you use negative lead filtering, you can rectify the
voltage across the choke for a low current bias source, while reducing the
insulation requirements on the choke.

I guess that resonant choke inputs are not used in the 'professional'
amateur amplifier for cost reasons - a string of electrolytics is much
cheaper. However, you can get much better regulation with a tuned choke, and
lower peak currents in the rectifiers and HV xfmr.

73 Peter G3RZP

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