>Gentleman is it possible to run an 8170 from single phase 240v? What
>would be better a choke or capacitor filtered power supply?
>
Depends on what mode, John. I ran one with a C-filtered 9kV nl anode
supply, but only on SSB. For CW I switched the supply to half-V. [see
Figure 3 in *Amplifiers*]. However, the resultant peak currents in the
electric-mains wiring were high enough to require #4 Cu wiring to the
radio room. If I had used a resonant-choke anode supply, I would not
have had to procure the uncheap #4 Cu wire. The trade-off is that a
resonant-choke HV supply would have been larger, heavier, and more
costly. If I had it to do over again, I would use a resonant-choke
supply. However, I'm guessing that one does not need a 3A supply. For
SSB, I'm guessing that a 1.5A resonant-choke would perform acceptably.
If you are going to use a Dahl hipersil transformer, remember that Dahl's
ratings are for continuous current, not intermittent current. IMO, for
such an amplifier, a secondary V of about 10kVrms, with taps, on a c.6kVA
core would be appropriate for SSB-voice and QRP CW and RTTY. .
- I would be using an 8171 instead of an 8170. It's the same tube
internally, but the 8171 has a more efficient anode cooler, which allows
one to us a quieter lower-pressure blower. For instance, the 8171 cools
adequately for ham use with only 0.4" air pressure drop across the
SK-300A socket.
- There's a J version of both bottles that has increased peak emission.
The extra filament current need for the J is only about 1/3. Improved
IMD results. IMO, cleaner is decidedly better with such machinery.
- Rich -
R. L. Measures, 805-386-3734, AG6K
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