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Two Turntables and Hum Problems - Help Please

Hello.

I've got two vintage turntables and both are giving me fits with hum.

I have two separate audio systems. One turntable goes to my pre-amp and the other to my receiver. Each system has its own separate sub-woofer.

My pre-amp and my receiver are about 30 feet or so from the turntables. That's as close as I can get them. Obviously each ground wire is much shorter than 30 feet. What type of ground wire can (and should) I use to replace what I have now that is not working? Copper stranded? Copper solid wire? Silver-colored wire? Should the ground wire be coated in plastic or rubber or should it be raw?

I've seen some references to sub-woofers generating hum from turntables through ones' pre-amps or receivers. Any thoughts?

Thanks!
snazz123
stanwal's avatar
stanwal
3,147 posts
 
Let me understand, you are running 30' of ICs BEFORE the signal gets to the phono stage? Remember the cartridge generates a VERY low level signal compared to a CD player, tuner, etc. If I had to place my tables that far away I would buy a cheap phono stage to put next to them; this very long cable run may be the source of your hum; in any case it is a big no-no.
elizabeth
6,726 posts
 
Just not reasonable to expect to run thirty feet of interconnect from any TT.
IF you must have them away from the equipment, you need to get some separate inexpensive phono preamps and have them next to the TTs. Then you can run a long wire from the phono boxes to your other equipment.
Also, the ground wire from the TT has to go tothe same place as the interconnects. That ground wire can be any small gauge wire of nearly any type.
Solid, stranded, as small as 30 gauge, or as bigas 10 gauge. a normal 18gauge lampcord wire will do to.
The mani thing as I mentioned it has to ge from the TT TO the same box as the interconnects.
etbaby
137 posts
 
Three suggestions:
First hum...the ground wire may not be the cause of your hum it could be the interconnect between the pre amp and turntable. This can occur if the interconnect has been placed too close to a power cord of any kind.

Note placing the power cord or the interconnects at right angles to each other may not solve your hum problem. Only distance between the power cord and interconnect will make a difference.

Second...
Replace the 30 foot section of ground wire with a single contiguous piece of 20 to 24 gauge wire.

Third...
When your cartriage output is only 3 to 4 mv, 30 feet is a long way for the signal to travel without picking up noise. Can you use a step up transformer for the cartriage to boost the signal over this distance?
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