Hi Phil:
Take a look at the Henry amplifier. Instead of using a wafer switch, at
least some of the amps use a group of cams to operate switches. It would be
fairly easy to duplicate those cams to make your own switch. If you are
using a tetrode with a passive grid, then you would only have to switch the
output. This mechanical arrangement is especially good for that situation.
Otherwise, the complexity associated with switching the tuned input and the
output would add a lot more complexity.
The Henry is especially nice for maintenance of the contacts as they are
easily accessible and does not require disassembly. It seems like most of
the commercial amplifiers I service always have something broken that
requires the front panel to be removed.
I think Mr. Murphy should have provided in one of his laws that the part
most likely to break is the one least accessible. If you make the part you
are most likely to break by "self-induced" error more accessible, it
probably will not break. Of course something else will.
73, Colin K7FM
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