Interconnect parellel to (low) power cable

I know about the science of running interconnects close to power cables. But I assume this mostly is about the 230V/110V AC power cable between the socket and equipment. What about the lower voltage DC cables between your PSU and other equipment?

I have, by necessity, my phono interconnect running relatively close, and parallel (for ~35cm), to the cable between my TT and its PSU, and I've never really had any hum or other issues. So that got me thinking. I have a new phonostage on the way, and the ideal (from aesthetics & usability standpoint, but also keeping the phono interconnect as short as possible) placement would require the cable to it's PSU run parallel (for ~50cm) to the interconnect between the phonostage and the preamp.

What's the science here, it's likely much lower voltage, and DC, not AC. Would there be any issue setting it up like that?

I've tried googling this, but the terms are a bit too generic it seems, so hard to figure out.

 

For future readers, answers received elsewhere:

 

I don’t worry about any wiring for home hi-fi. Haven’t for over 45 years.

 

Phono cables (from the TT) are the only ones I take care with, their signal level is so lo
4 mV
85 uA
That they are susceptible to emi/rfi
But good cables are shielded/twisted which mitigates it.