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
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
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.
The gauge of the rca extension cables won't make any difference. What is important, in addition to shielding effectiveness (which is hard to predict) is (as I mentioned earlier) keeping cable capacitance as low as possible, particularly if you will be using moving magnet or other high output cartridges. I suggest Blue Jeans LC-1, which provides very low capacitance per unit length at a relatively low price.

For purposes of minimizing hum, the kind of grounding wire you use is not critical, as Elizabeth indicated above. I suggest initially experimenting with whatever is handy, or whatever you can get cheaply and conveniently at Home Depot, Radio Shack, etc.

If and when you eliminate the hum, however, you may then find that you are picking up radio signals or other interference. To address that kind of problem, the best type of ground wire would be a "braided ground strap." Google that term for further info, if necessary.

Regards,
-- Al
Continued thanks to all for your suggestions. I'll let you know how I make out once my schedule slows down in a few weeks.

Since I cannot reduce the distance the between the two turntables and the respective pre-amp and receiver, Elizabeth and other suggest getting inexpensive phono preamps for each turntable. I'm looking at some that are about $50 each. Does that sound right? Any brands anyone suggests, in particular? Does jumping straight to getting phono preamps (I may even have one in the attic now that I think of it!) sound like a good starting place (before changing the extension phono cords to better shielded ones, before replacing ground wires, before disconnecting cables to my two (separate system) sub-woofers? Thanks folks!

Wayne
I just dusted off an old Kyocera TT with a Blue Point cartridge and bought a Bellari 130 (tubed for $250) and couldn"t be happier. I'll be upgrading soon but for now the Bellari sounds way better than $250.