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I have a keyboard synthesizer which emits a 60Hz hum due to mechanical vibration of its PSU. The vibration is magnified by the metal chassis of the synth which acts as a soundboard. It’s very annoying in a quiet home studio. The manufacturer does not consider this a problem and is unwilling to help.

What can I do to dampen this vibration? I was thinking of installing some rubber washers between the PSU and the posts it sits on, but I was concerned about blocking paths to ground (labeled M1, M2, M3, M4 in the picture below).

Power supply in situ

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  • \$\begingroup\$ Have you confirm that those mount holes are actually connected to ground, earth or circuit? \$\endgroup\$ – Matt Young Apr 8 '15 at 18:17
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Isolate the mounting with rubber grommets, and if grounding is a concern, crimp a ring terminal to a wire, secure it to the mounting between the supply and one or more grommets, and tie the other end to a convenient point.

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The larger Allen & Heath analog mixing consoles have 19" rack-mounted power supplies with a DC cable to the console itself. This carries all of the separate DC voltages that the console needs: 16V-0V-16V for the signal path and LED's, and +48V for phantom power.

Perhaps you could modify your synth to do something similar? Remove the internal supply, put it in its own box, and reconnect it via multicore cable? You may or may not need to move or duplicate the supply's output capacitors inside the synth again, but that shouldn't be hard.

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