My Impossible hum issue.


I have done everything that I have read about ground loops without success. My system is on an outlet that goes directly to the main panel with nothing else plugged into this circuit. None of the usual suspects are in this room like TV, radio, appliances or flourecent lighting. When using any other source other than the turntable, the system is dead silent. The turntable is on a wall mount turntable shelf. The speakers are on stands. This hum is only present when the turntable is the source. The hum is much louder with a MC cartridge than a MM cartridge. The hum is present when connected to an external phono preamp or the internal phono preamp of the my system preamp. I have tried every combitnation of grounding and not grounding. Whether or not I plug into the wall outlet or power conditioner/surge protector the hum persists. I beleive that I have tried everything except a different turntable. I have made sure power cables, speaker cables and interconnects don't cross each other. I've tried everything except moving to another state or hiring an exorcist.

Ag insider logo xs@2xadamsrpm

I had a Revox linear tracking TT with a persistent hum issue.  Because of very limited space in which to relocate it, I got this item on Amazon:

 

Electriduct 1/2" Tinned Copper Metal Braid Sleeving Flexible EMI RFI Shielding Wire Mesh (0.32" Diameter) - 25 Feet

 

It's a braided metal sleeve that you can slip over the IC.  it ended up solving the hum issue...at least in my case.

@adamsrpm  I'm brand new here and I thoroughly enjoyed your post and am so glad your problem is fixed! ✌️ I'm learning so much in the forums. Thanks everyone. 😀

The hum problem is an issue that occurs in most professional music areas. The solution is to install ISO Max transformers. It will cost you about $200 but will solve any of your hum problems.

etbaby, I don't think an isolation transformer would solve the OP's actual problem, since the short in the ground connection occurs AFTER where the ISO Max transformer would be inserted, between the AC source and the power cords. He had an interruption in audio ground.

I had a persistent 'hmmm' for a time that drove me sane....

And, as noted, a funky cable not grounding well.

Took persistence to track it down, and the obviousness of it... 🤦‍♂️😏

Glad you were able to find yours.... 👍👌