[Elecraft] KPA500 AUX input

[Guy Olinger K2AV]

Running two separate sinks off the same source is always a crap shoot
unless you have analyzed the circuitry of the sinks and the source and
specifically determined that they are compatible in all states, which
must include all combinations of power on and power off states in all
three devices. And you have to be correct in your analysis -- physics
is no respecter of persons. There are no rules here other than to
actually run them in parallel without isolation is the lucky
circumstance.

It will be easier to do the isolation to start with than figure out
the facts of your particular combo, particularly since the most likely
outcome is that you need to do the isolation.

73, Guy.

On Sun, Apr 24, 2011 at 8:10 PM, Ralph Parker <ve7xf at dccnet.com> wrote:
> I ask this question in advance of the amp actually arriving, so I can't try
> it myself to see if it works. Maybe it's an 'Eric' question anyway.
>
> I currently use the AUX output from the K3 to drive my 'Top Ten' type band
> decoder (actually, it's a W9XT) to drive the antenna selection relays .
> Having an early K3, the pull-up resistors are in the decoder, not the K3.
>
> The question, should anyone venture an educated guess:
> Can I drive the KPA500's AUX input in parallel with my existing decoder
> using a Y cord, or should I isolate the K3 from both the KPA500 and W9XT
> with diodes?
>
> Ralph, VE7XF
>
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