How are phono cables different (related to hum issue)?


Wrestling with frustrating humming for weeks on a new TT. Finally inserted the cheap stock phono cable, and the hum is nearly gone. Was using spendy phono cables bought separately prior. So what's the sitch here? Shielding? Cheaper = carrying less signal? I was using the ground wire with both (and tried without, twas worse). Glad the hum is gone, the sound is duller but removing the hum makes it almost worth it. Of course now I need the color back, but not the hum. 
128x128zufan

Showing 1 response by millercarbon

The problem is not so much the cables as the gain. The tremendous gain in a phono stage, from millivolts to volts, means any noise whatsoever is large relative to the weak cartridge signal. So the cable can be really well made, and one bit of oil or dust on the connector, any little thing, and you can get noise. Sometimes an incredible amount. I've heard radio station broadcasts you could make out the music! Then you touch something, poof! Gone. Sometimes never to return. Other times.... 

It may turn out that your "better" cable is indeed the culprit. I had one that had been used for years just fine develop a noise that took forever to track down to a weak solder joint inside the RCA plug. Unfortunately this is one of those things all you can do is try one thing after another until you either figure it out or give up and buy another cable.

I would start with what Keith Herron suggested to me, plain old alcohol on a clean cotton cloth. Because sometimes even contact cleaner/enhancers leave a film that can cause a problem.