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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.

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vinci92
18 posts
 

If your telecommunication provider is coax cable based, this 4k compatible filter and available at Amazon.ca, could be the end of your nightmare.Works perfectly for me : 

Isolation Transformer / Ground Loop Isolator https://a.co/d/dAvbDC1

lewm
12,524 posts
 

More to the point, you might contact Pangea or your vendor and ask for a return authorization, on the basis that their ICs seem to have an internal short circuit on the ground side. By "internal" I mean that the issue probably is inside the insulating sheath or outer cover OR it's at one end where the wire is soldered to the ground side of an RCA plug. (It's unlikely to have been a problem with an AC cord; in that case you would have no power to the TT.)

hz79hc's avatar
hz79hc
24 posts
 

I noticed you're using the same preamp I have (Parasound P6).  I have likely missed other messages prior to those I just scanned.  Tell me, did you try simply using the phono stage in the P6 rather than your separate phono amp?  No compelling reason to I suppose but that's likely an easy check.

I have no reason to be optimistic but the head shell comment may have merit.

Best of luck.

 

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adamsrpm OP
12 posts
 

Yes, I did connect the turntable directly to the Parasound P 6 with the same result. When going back to the turntable's stock cables, the hum stopped. Now I need to find some quality phono cables that don't cause a hum

Any suggestions for a phono cable at $100 level?

mahler123
3,062 posts
 

Congratulations to the OP on solving the problem.  I am going to commit audiophile heresy and suggest that he leave well enough alone and go with the stock cables.  Perhaps he can do research into the company that makes the stock cables and see if they offer higher end cables that use the same basic design.

  I am curious as to why the hum is worse with mc cartridges.

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