PC to SX-950 hum

[HairySatchel]

I'm running dual RCA cables from my audio card to an SX-950 and out to passive monitors. The hum is really bad and any mouse movement makes it worse. I noticed my receiver only has a two prong plug and is plugged into the same circuit as the PC. This happened once before when running RCA cables straight out to powered monitors. I tried a bunch of things but never did find a solution. Any Ideas on how to get rid of this horrible ground loop would appreciated. Has anyone tried those hum eliminator devices? Do they work? Thanks

 

[mbz]

Think this might be the case where the PC and SX-950 have different ground voltages.
Think the "theoretical" solution is to connect the PC GND to the SX-950 GND/Chassis
but I don't have a GND on my laptop, haven't used a tower in years...

 

[Watthour]

The serial bus in the PC/laptop can broadcast random energy, and almost none of the USB cords and cables have any kind of shielding. I've noticed that on my workbench. I've not yet experienced that with a sound card, but there are a lot of different card design out there and their degrees of isolation might vary greatly. The case of the PC should be its ground, just like the chassis of your 950.

Further, the data bus in the PC is also clocked at a rate where 2nd and 3rd order harmonics can interfere with RF, and it's worse on AM. I have to shut off my workbench PC when aligning anything.

 

[zebulon1]

Switch mode PS's generate a ton of RF which can find its way into any cord.
Separate the equipment using a Bluetooth system?
Maybe a longer RCA cable? The sound card might need a look see? Some are made for high quality recording.

 

[sawdust]

I had the same problem in my shop I eliminated the ground pin on the computer plug and stopped the hum.

 

[HairySatchel]

I bought an inline transformer. It worked and the hum is gone.