2. analog
  3. 183309-178493

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
asvjerry's avatar
asvjerry
4,608 posts
 

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.... 👍👌

wyoboy
261 posts
 

I upgraded from these a couple years ago but haven't really heard a difference--may be my hearing or may not but these are very low capacitance (essential for phono cables) and in your budget--i think Belden makes them for BJ:

 

groovyjeep's avatar
groovyjeep
5 posts
 

If all else fails, get a Radial Engineering J-ISO or similar.  basically a 1:1 transformer for audio signal and it will at least prove whether it's possible to eliminate the hum.  I've used mine at various points in the signal path for troubleshooting

papafrgog
102 posts
 

OP, read your post and I have experienced a similar issue (and commented on it before) with TT/LOMC and hum/hiss in background. I know how frustrating this was for me, and feel your pain. 

My problem was caused by my wireless router and likely poor insulation on my ethernet cable to my streamer.  I was at the same height and about 6 ft away from my TT.  When I disconnected and it totally, the hum went away.  I relocate the unit to the floor about 20 ft and haven't looked back.    

If someone has already mentioned this as a possible fix, my apologies for not reading through the posts. 

More to discover