Sometimes builders use more than one RF choke and a
vacuum relay to switch the additional choke into the
circuit to arrive at enough inductance to prevent RF
power from entering the power supply at lower
frequencies.
A vacuum relay is not necessary. I use a method taken from
Creative Electronics. All you need is a Radio Shack relay.
B&W manufactured a successful RFC for amplifiers
called a Type 800 and then a type 802. They had
ceramic cores and fit most chassis situations, but
their wire guage was this and they aren't able to
handle the amperages needed on some big tube
amplifiers.
A choke sold by RF Electronics and sold/used by Ameritron
costs c. $23, and is resonant around 11.5 mhz, well outside
all ham bands. It will do 2 amps with no problems at all.
(((73)))
Phil Clements, K5PC
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|