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
Lifting the ground makes the amp hum more

This is a "Stereo" setup only - amp tuner, DVD(i.e. CD) and PHONO - no TV/AV components or connection to cable equipment.

Thanks for the info though - I'll tuck that away for future use
If I understand your post correctly, it sounds to me like you've got a defective interconnect (or two) somewhere.

I think you are saying that with ALL of these components simultaneously connected into the system, if you connect your meter between the ground sleeves of various rca connectors and safety ground on the power strip, in some cases you see a substantial voltage and in some cases you do not.

If that is the correct interpretation, it would seem to say that a cable somewhere is not properly tying the grounds of the connected components together.

Regards,
-- Al
Water your service ground.

or, re-establish a better connection where the ground lug attaches to the ground rod. IOW... take it off and clean it up... then reattach it. This might also be a good thing inside the service panel to do.

An inductor on the neutral line might also help. you can make one by using some #14 or even #12 solid wire by making 10 to 20 loops tightly wrapping from palm to elbow, round and round again, and then using some tape to keep the loops together... open the receptacle and splice in the DIY inductor on the neutral side with a pr of wire nuts.

The more loops, the greater the effect.

There's a difference of potential and I suspect as Al said a poor connection, though in either the breaker box in the home or at the service panel outside on the power pole.

naturally, swapping out the ICs is the easiest thing to do first.

The netral bus bar and ground are tied together in some areas of the country too and loose bars or connections might cause such a thing too. As could plain old corrosion and loosening of the screws on the bus bars themselves.

...and/or in the outlets.

good luck.
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.
Williewonka 06-24-10:
between the neutral side of the interconnect and the earth at the power bar.
Williewonka,

Not sure what test you preformed.... Can you be more specific. What do you mean by "neutral side of the interconnect"?

Lifting the ground makes the amp hum more
06-25-10: Williewonka
Are you sure the sound you are hearing is a hum and not a buzz. Does the noise vary when changing the volume level?

I just purchased a NAIM integrated amp and I am experiencing a hum but only from the DVD player.
06-24-10: Williewonka
I would try what Al said in his post. Could be a bad interconnect. Could be a bad signal ground solder connection inside the DVD player.
Does the hum/buzz change if you put your hand on the metal case of the DVD player?

I would also try another set of line-input jacks on the NAIM.
Post removed