Phono Cable Question

[James Edward]

I just moved my new table into its final resting place. This required disconnecting and moving everything around. I figured I would try more pimpish cables than what was supplied by Pro-Ject. I also ran a separate ground wire from the table to the integrated amp.
Voila! An extraordinary amount of ground hum greeted me when I was testing everything prior to pushing it all back. I put the supplied Pro-Ject cable back in, and the hum is gone.
Any thoughts?

[Folsom]

Shielded vs unshielded.

[James Edward]

Yes Mr. Folsom. After I posted the question I did some reading, which I guess I should have done prior... 

[James Edward]

Just to further my own knowledge... A number of companies offer unshielded cables as a better sounding alternative. Did my problem occur because the phono signal is very low compared to CD, tuner, etc. I ask because I use the same cable for my CD player with no noise whatsoever.
If so, I would imagine low output MC cartridges require even more TLC in setup and wire dressing...

[Folsom]

That is a big part of it. Even if a little hum got into your unshielded interconnects from CDP, that signal isn't increasing 40-70db once it gets to the destination, so it likely is entirely unnoticed. But also because of the nature of things it's unlikely to pick up a bunch of hum to begin with.

Imagine this, your phono RCA cable is two wires, and it goes to the turntable where it's still two wires all the way up to the cartridge, and inside that the two wires are wound into a tight little coil where they connect in the center. Both channels are like that. They're nothing more than a big loop coming off the phono preamp - that's wound up tight at one end. So the only thing you can do is try to use one side of the loop as a shield by wrapping it around everything, and not using anything on it for signal.

[steve]

Just to further my own knowledge... A number of companies offer unshielded cables as a better sounding alternative. Did my problem occur because the phono signal is very low compared to CD, tuner, etc. I ask because I use the same cable for my CD player with no noise whatsoever.
If so, I would imagine low output MC cartridges require even more TLC in setup and wire dressing...

Hi James,

I second Folsom's recommendation, you want a shielded cable.

---------------- For general consumption for all.

Although not part of the OP's question, obtain one with minimum capacitance if you can as the capacitance can affect the highs, even if the peak resonance is in the ultra sonic region. And if you eventually change to a Moving Magnet (MM) or Moving Iron (MI), then the cable capacitance will make a huge change in sonics.

With Moving Coil (MC), one is usually concerned more with the cartridge load resistor, although large cable capacitance differences can affect the sonics.

The below link will show the problem of peaks with different load resistances.

http://www.hagtech.com/loading.html

Cheers
steve