Dean Aukes asked about an R.L. Drake DC-4 power supply he had been given.
Several people replied, correctly, that it won't convert 12V DC to
anything like 120V AC / 60 Hz.

The DC-4 was designed to power Drake's TR-4 ham transceiver (which
had a lot of tubes in it) from a car's 12V system.  It mainly
put out several different DC voltages for the transceiver, but also
had a 110V AC output jack for powering certain station accessories.
The frequency of this AC was 330 Hz (approximately), because the
DC-4's transformers could be considerably smaller that way.  The
switching circuit which "chopped" the incoming 12V DC operated
at that higher frequency.  

Some electronic equipment will run quite happily at higher frequencies,
but not all, and I wouldn't risk trying.  For sure, nothing with
an AC motor in it will run...

On the other hand, if you are a ham and have a TR-4 lying around,
it'll run great!

Ted Zateslo, W1XO
zateslo@gly.fsu.edu