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

You have a ground loop issue. Neutral is grounded at the main electrical panel box however the length of cables and a poor contact somewhere (or a cheater plug) to the equipment can allow a small stray voltage to build up from some power supply leakage to ground (coudl be a faulty component). An RC interconnect will provide the return for a small stray current and hence you will induce a hum in the line level signal. With RCA you always have this problem to a greater or lesser degree - although the hiss or hum may often be low enough not to be of significance in a system with low dynamic range.

Guys, I think we need clarification from the op, as I implied in my earlier post and as Jim requested. My suspicion is that the reference to 1.5 to 2.0 vac on the "neutral line," on some components only(!), does NOT refer to the ac neutral.

For one thing, he referred to "the neutral side of the interconnect." Also, how would he be able to measure the voltage between ac neutral and ac safety ground individually for each component, without opening it up and probing internally under the chassis?

So as I indicated in my earlier post, I suspect he is referring to an ac voltage between circuit ground (as measured on the ground sleeves of rca connections) and ac safety ground. As Jim and I indicated earlier, if he is seeing a significant difference among those readings for different components, while the components are interconnected, he's either got a defective interconnect or a defective circuit ground connection on one or more of the rca jacks. Either of which could certainly account for a hum problem.

Best regards,
-- Al

I gave a complex answer. Here are a few simple solutions.

If the NAIM has an optical in then try that.

Disconnect the video to the TV and see if the hum goes away - if it does then check your TV is grounded properly (no cheater plug).

Whatever you do - do NOT use cheater plugs on the Naim or on the TV - this can expose you to dangerous voltages in the event of an equipment failure.

Shadorne

Whatever you do - do NOT use cheater plugs on the Naim or on the TV - this can expose you to dangerous voltages in the event of an equipment failure.

I don't recommend using them as a long term solution, but they're perfectly fine for troubleshooting.

You also need to measure the RCA neutral to the case of the
equipment for voltage difference.If it there,that could be inductive pickup from the case housing the transformer, especially in a power amp with a big transformer.If the difference is between the neutral and ground at the outlet, that just may be the load on the feeder causing a voltage difference.This may be normal when there is a load
on it.Like mentioned above,clarification is needed.The power bar may be all metal,and tied to the outlet ground.
I go with the more clarification needed also.