[Amps] Amplifier for 630 meter band

[Catherine James]

I'm starting to think about building a transmitting station for 630 meters next spring. I've filed my UTC request and expect it to be approved.

I think it will be much easier to start with an existing amplifier and modify it rather than building from scratch.  I have no sheet-metal-working experience and I'm not interested in putting in the time and effort to learn that skill.

Something like a junk SB-200 with a good power supply and burned bandswitch seems like a reasonable starting point. Good 572B tubes are once again available from RF Parts.  I'm sure there are many other models of tube amp that would work.  It will probably depend on what I can find available.  Replacing all of the filtering and tuned input/output circuits seems pretty straightforward. Some pretty hefty capacitors and inductors will probably be needed.

What are everyone's thoughts on a simple, inexpensive conversion of a 500 watt  amp for 472-479 kHz?