I finally found the time to work on my Titan 425 amplifier, trying to
reduce the noise radiated (mechanical noise, radiated acoustically) by
the vacuum relay. I removed the relay board and found the grommets that
hold the relay to be quite hard. The new grommets I had available, that
had the correct inside diameter to fit around the relay, have larger
outer diameter than the originals. I bored out the hole in the PCB to
accommodate the larger grommet, seeing no problem in doing so, and
hoping that more neoprene between the relay and the PCB would equal
greater vibration isolation. I used short lengths of either "Flexweave"
antenna wire or copper braid to go between the relay terminals and the
stiff wires that were formerly connected directly to the terminals.
While soldering the braid or flexweave wire, I kept some needle nose
pliers firmly gripped onto the wire to prevent wicking action of the
solder into the braid/wire. I wanted the braid/wire to remain as
flexible as possible to reduce the transmission of vibration through it.
It worked. The noise from the relay is much lower than before. It is
still not as quiet as my Hercules II. The Hercules II has a completely
different mounting scheme for it's vacuum relay, which would be much
more effort to try to duplicate in the Titan. The coil voltage label on
the Titan 425 vacuum relay is 12 VDC, so I think it is the same model as
what the Hercules II uses.
I guess I spent a couple of hours on this project. I enjoyed it and am
happy with the results.
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