Why is a 1.5-2 volt AC signal on my Neutral line?


I have several music sources e.g. DVD, Phono, DAC, Tuner etc...

I just purchased a NAIM integrated amp and I am experiencing a hum but only from the DVD player.

I have circuit tested the entire house wiring and all is well.

After a lot of investigation I found that some units have a 1.5-2.0 volt AC signal (sounds like a 60Hz signal i.e. hum) between the neutral side of the interconnect and the earth at the power bar.

Panasonic, Pioneer and Sony units I have measured all have this signal present and it varies between 1.5 - 2.0 volts

Luxman and Cambridge Audio gear does NOT have the signal present

All units have a polarized plug with no ground pin

How can the hum be eliminated using the Pioneer DVD with the NAIM Amp?

Thanks
williewonka

Blindjim

Water your service ground.

Service ground has absolutely no relevance at all.
Simply_q

it'll sure tell you if there is a weak connection there.

it's certain there's a weak connection, or resistive connection somewhere , if not in one of the devices, then it has to be in the service.

I'm figuring the house is older than the equipment and felt to start from the begining ... at the service pole and follow it back to the outlets being used. Skipping around looking at this or that seldom plays out well.

I've seen far wierder stuff happen.

Blindjim

it'll sure tell you if there is a weak connection there.

No it won't. The ground road has nothing to do with your audio system or with any ground loop noise in your audio system.
Blindjim,

A difference of potential, voltage, measured at an electrical outlet measured from the neutral to the equipment grounding conductor can be the result of VD, voltage drop, on the loaded neutral conductor. If the resistance of the equipment grounding conductor is less than the resistance of the loaded neutral conductor then there can and will be a difference of potential between the two conductors.

VD is directly proportional to the size, length, and load placed on the conductor.
Poor connections along the length of the conductor can cause higher resistance in conjunction to the amount of load placed on the branch circuit neutral as well.

As Simply_q said in his post the main service earth ground connection does not come into play. In most cases the branch circuit neutral conductor as well as the branch circuit safety equipment grounding conductor terminate on the same neutral/ground bar in the main electrical service panel.... Sub panels will have them separated on two different bars but they still end up tied together at the main service electrical panel via the feeder neutral conductor and equipment grounding conductor. Both connect together at the main panel.