Thread: EB63 update
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Old October 22nd 04, 04:14 PM
Frank Gilliland
 
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On Fri, 22 Oct 2004 08:17:01 -0500, "Chad Wahls"
wrote in :

snip
Frank said it would be a moot point to have RF rejection in this area, do
trust him more than me as he has WAY more RF knowledge than I do......



Sorry, I wasn't trying to step on your toes. You probably didn't know
that the input impedance of these transistors is about 1 ohm (with a
little reactance), and I think you will agree that any pickup by this
resistor (or other relatively short wiring in the low-impedance part
of the circuit) isn't going to amount to squat. Regardless, any RF
that happens to land on the center-tap of the input transformer will
end up as common-mode signals that will be nulled at the output
transformer.

The most likely cause of self-oscillitory feedback will probably come
from the relay. Notice that one relay is used for both the input and
output (both at higher impedance than the amp block), and that the
armatures are long, parallel, and relatively close together. Scary!
Even Pride, the company that produced some of the worst CB amps ever,
had enough sense to use two seperate relays.







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