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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
swanny76109
382 posts
 
the subs could be a problem too, as the OP offered up.
almarg's avatar
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almarg
9,670 posts
 
In addition to the good comments above, another reason that a 30 foot run from turntable to phono stage is unreasonable is cable capacitance. With a moving magnet or other high output cartridge, sonics will be significantly degraded unless you use a cable having extremely low capacitance per unit length AND the cartridge is specified to work into high load capacitances. With a low output moving coil cartridge that may or may not be an issue, but the likelihood of noise problems will increase significantly.

Get a separate phono stage, as Stan and Elizabeth suggested.

Regards,
-- Al
hifihvn
943 posts
 
I've had signal degradation with 12 foot cables from the turntable. You may not realize it unless you could compare the shorter length first. Upper end treble loss, no air, and it was just plain boring sounding. If I didn't know how it sounded before the longer cables, I may have blamed a lot of other stuff first, and wasted money.

Running a 18 awg for the ground temporarily may help hum.

In the long run, move them closer, or get a phono stage as mentioned above.
snazz123 OP
3 posts
 
Thanks, all, for your suggestions. The length is more like 18-20' not the 30' I mentioned originally. My setup and physical layout of the room and the audio rack preclude my getting the two TTs any closer than they are currently. I'm going to distill the advice you've given me and try to solve this issue. I've had a busy schedule recently but must try removing the sub woofers from the equation, temporarily to see if that helps.

Getting 20-24 gauge grounding wire might be another step but I'm still not sure what kind of wire I should use. Hmmmm.

The extension phono cables could also be an issue. Perhaps a heavier gauge of female to male RCA phono cables could help things. Thoughts?

Thanks all. I'll check back for further responses soon.

SNazz
roscoeiii's avatar
roscoeiii
1,155 posts
 
18-20 feet is still mighty mighty long for a cable transmitting such a miniscule signal. Above all other cables I would try to keep the phono cable as short as possible (and make sure it was shielded). Without shorter phono cables (or maybe balanced cables) I would be surprised if you are able to get the hum out of the vinyl setup.
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