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Ground Loop Issue - PM-1000 - Any ideas?
Old 6 days ago
Ground Loop Issue - PM-1000 - Any ideas?

Hey slutz,

I recently overhauled a PM-1000 by recapping and installing transformer direct outputs on each channel. The direct outs are wired up by DB25 connector and I have the ground connecting to the chassis. Sometimes, I want to use compression on the way in, so I route the necessary channel to one of the monitor outputs. On all of the monitor outputs, there is a ground hum.

Do any of you guys that are way smarter than me have any ideas where this could be coming from? Could it be the ground from the DB25 connected to the chassis?

Thanks in advance!
Old 6 days ago
Lives for gear
Check your other outputs.
Any hum on the main outputs?
Any hum in the direct outs?

Did you recap the master sections as well? Maybe there is a poor connection to ground that needs to be reflowed somewhere around the monitor outs section.
Try disconnecting the ground on the db25 and see if it’s any better.

Maybe there is a better place to attach the ground.
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