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Old 20th May 2019
Lives for gear

Originally Posted by toledo3 View Post
When you have something like that happen it can be because of multiple ground potentials, and lifting ground can fix it.

But if it’s because there is a problem with ground connectivity in the first place, then ground lift will not fix it.

You got rid of the PSU already, but in a similar scenario I would figure out where the grounding inside the 500 series module is expecting to resolve, then follow the connection into the PSU, and down the path, making sure there are no problems along the way. Can even be something a stupid as one of the pins not making solid contact.

The other thing that can happen is that the transformer involved in the PSU might be causing some hum to pollute the signal of a given module. Sometimes just reorganizing the rack so that a susceptible module is physically further from the PSU power transformer can be a good idea. PSUs that use toroidal transformers can help too.
But the new rack has zero hum. Wouldn’t that eliminate the possibility of a ground problem in my space? Honestly, I thought it would but I know next to nothing about this level of electricity and engineering.

I did try the Daking in nearly every slot and in just about every possible place in the room. The tech at VK also said he suspected a faulty power supply b/c of the frequency of the hum and that it increased with gain. He said that last point especially eliminated it being a ground hum.

All I know is that the problem is gone and all I did was get a different rack and power supply. I’m very glad I didn’t have to do wiring or install special material in my outlets