Cables CAN make a difference!

Today I was doing some routine measurements to make sure a bit of kit is working as it should with single-ended outputs.

Shock-horror it isn't working right! It looks like a serious grounding issue... oh dear. See the red trace in the graph below.

After lots of faffing about I found the noise was there even with the source equipment powered off. Eventually I tried switching out a cable (I just needed one with another connector) and the noise disappeared!

This is the first time I've EVER found a cable make so much difference. The result - cable in the bin. I don't know what is the problem with it because it has a copper twisted screen and a normal looking centre conductor. It's a phono cable that came with a JVC KD-720 tape machine in the 1970's.

Switching out this cable for a bit of Belden wire gave the blue trace.

 

40 years old thin cable. Likely a break in the screen/return at some point increasing the impedance to ground, or it's just very poorly/thinly screened - given the mains bump.

Still going to be inaudible though with a fundamental at -90dB and harmonics at -110db

 

cables

During the 1970s I knew someone who did "homework" making Phono cables.He got so much per hundred.He had his wife and child helping him solder the connectors on to the screened cable.
Not a lot to add to that really,except to say that I always made my own.
Pete.

 

cables are always system dependant, they can vary the signal fhz path all round, how ever it does not the case the more expensive they are the better they sound, a great myth it is, we all know pure copper at least 99% pure is the almost perfect conductor.