Cables CAN make a difference!

[Tenson]

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.

 

[RobHolt]

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

 

[pete693]

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.

 

[nando]

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.