Message Boards

Ground loop(?) problems, once again

juha-palomaki, modified 5 Years ago.

Ground loop(?) problems, once again

Youngling Posts: 1 Join Date: 7/13/11 Recent Posts
I'm trying to debug my ground loop(?) problems and would appreciate some help.

Test setup: Genelec G2, connected to power outlet. Normal RCA - headphone jack cable connected to speaker, but not to any device. If I touch with my finger to the headphone jack, I hear a very strong static noise. Measured with iPhone that the frequency is 452Hz or 344Hz. (Same sound is also there when I connect to my hometheater amplifier). I tried different sockets on different floors but that does not make any difference.

I also tested G1 in similar way and the same noise is there. I tried turning off some obvious candidates like air conditioning, freezer and fridge but that did not seem to have any effect.

I have also a pair of M040s and pair of 8030As. With those I haven't noticed any problems, but they are all connected with balanced cables to Cambridge DACs.

Any ideas how to investigate this further?
ilkka-rissanen, modified 5 Years ago.

Re: Ground loop(?) problems, once again

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts

It is perfectly normal to have noise when touching the signal cable like this. But do you say that you get the same noise when signal cable is connected to your HT amplifier? Typically those have RCA pre amplifier outputs but you are using a 3.5mm headphone jack? Have you tried any other devices with headphone output, for example laptop or mobile phone? Is the noise always there?