Annoying white noise through NAC-N172XS

A few days ago, I replaced the speaker cables in my equipment. Since then, a rather noticeable white noise can be heard in the preamplifier. As it is known, this equipment doesn’t have a power switch or standby mode, so the noise is particularly annoying in the evenings and at night.

When I connect the preamplifier to the power supply, nothing can be heard for a moment, but after a while, the relays activate, and then the noise begins. Interestingly, activating mute changes nothing. The intensity of the noise also doesn’t change with the volume level. So, the noise level is practically the same all the time. It also doesn’t matter whether the switch at the back is in the ‘floating’ or ‘chassis’ position.

When I connect headphones, the noise disappears. I don’t notice any noise on the headphones. There’s also no noise on the ‘line out’ signal output.

The NAC is connected with a DIN/XLR cable to the NAP-250DR power amp. I wondered if connecting the cables at the back, one of the signal cables might have moved and is now picking up interference. I use a turntable, CD player, and Blu-ray player, but I am rather skeptical. Do you perhaps have any idea what might be causing this and how to remedy it? Thanks!

Maybe it’s new speaker cables? why not put back what you had, see what happens.

I suggest you remove these. What are they?
There are cables that would be unsuitable.

And double check all connections are right in for all inputs. Easy to have nudged one half out.

AM radio static?

It happens. I once dressed my speakers cables differently and picked up a radio station. I thought it was the preamp because if the power amp was on but not connected to the preamp it was silent. But of course that was just because doing that breaks the circuit needed for it to manifest between speakers and source.