> >>In all this discussion, nobody has mentioned the bias switching. IMO,
> >>the amp should not be biased on until all the relays have closed and
> >>must be biased off before any of them open.
> >>
> >
> >/\ Please explain why.
> >tnx
>
> _________________________________________________________
>
> It will make it impossible for a tube to be momentarily unloaded, either
> at the input or output.
Bill, What actually will happen ios the tube becomes a dc cathode
follower, and the cathode voltage easily pumps up a bit higher than
you might expect.
Then the relay has to discharge any capacitors, plus handle some
instant peak anode current while bouncing.
That might wear on the relay, but I'm not sure at all it is any worse
than a small RF spark on the input relay.
My gut feeling is it is better long-term to not close the input relay
early or open it late...compared to the output relay. But that is only
a gut feeling.
73, Tom W8JI
W8JI@contesting.com
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