ORIGINAL MESSAGE:
On Tue, 13 Jul 2010 07:12:57 -0400 (EDT), Gudguyham@aol.com wrote:
>Obviously both methods work but just wondering the thoughts on one way over
>the
> other. Anybody have their preference?
REPLY:
As you say, either method can work. I prefer to connect the cathode
directly to one side of the heater and feed the RF at that point.
The main reason is to preclude a possible arc from cathode to heater.
While it is true the heater is insulated and will probably handle the
voltage, I figure why take a chance?
If you do this, be sure to connect the B- lead (from the bias zener)
to the side of the bifilar heater choke that goes to the cathode. If
you connect it to the other side, you will accidentally add the 5.0
volt AC heater voltage in series with he B-, leading to a small amount
of hum modulation.
73, Bill W6WRT
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