Hum only on one side and only with turntable

steeler80

New Member
I have a Elac Miracord 45 that is running into a Realistic STA-80 amp. The turntable produces a hum on the right side unless I remove that AV cable. When I reinsert the cable, there is a louder hum and then the speakers work correctly. They'll work through the entire album but, when the turntable drops another album the hum returns until I remove/replace the AV cable again. Neither the radio or connected tape and cd players produce the hum. Am I just dealing with a bad cable on the turntable or is there another issue? Thanks for the help as it's driving me crazy!
 
Swap the left and right cables and see if the hum is in the speaker on the side you swapped it to. This will tell us if it's in the tables wiring or the receiver.
 
Does your turntable have a separate ground cable or is it grounded through one of the audio channels? :idea:

As far as I remember, old Miracords have mute switches which engage when the automatic functions kick in. I can’t remember if they are sitting in the signal path or simply short-circuiting signal to the ground, but either way, your problem probably lies therein.
 
The hum switches sides when I switch cables. I had thought I had tried that before and couldn't hear anything, but today the hum switched and the other side was playing fine. I can't see any separate ground cable.
 
The hum switches sides when I switch cables. I had thought I had tried that before and couldn't hear anything, but today the hum switched and the other side was playing fine. I can't see any separate ground cable.

A few things can be wrong in the wiring from the cartridge to the RCA interconnects.

Unplug the contacts at the cartridge and plug them back in, see if they a tight/snug making a positive contact. Use the table again.

I don't feel it's a bad RCA interconnect because it happens after the arm starts moving.

It could be the tonearm wiring grounding out in the arm, but lets see if it's the contacts at the cartridge first.
 
Okay, I think I solved it. I was removing the headshell to inspect the leads when I noticed that the needle was tilted to one side. I gently pushed on the needle and it moved around a lot more than I thought it should. I put the headshell back on and the sound was terrible. So, I had an extra needle and put it in. That seems to have solved the problem. Apparently, the needle had become partially disconnected?
 
And I want to add a thank you to all your suggestions! I don't know if I would have discovered the problem with the needle if I wasn't looking at the cartridge.
 
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