Digital Contamination of the Power?

Jon2020hi.
Sorry to say but a power cord won't stop the digital noise or switch mode noise rubbish from entering the household wiring, and if your hi-end gear is close to it, the airborne rubbish as well.
It emanates like a cancer through the wiring and through the air.

Cheers George

Charles Hansen is right, anything with a smp power
supply can contaminate into the wiring of the house, and it's airborne efi as well.

Do an experiment, tune a portable AM radio down low on the dial around 700khz, so there's no music and it's not muted, just static, then go near to a smp power supply or class D amp and you will hear what rubbish rf rubbish emits from the speaker of the am radio.

I had a smp wall wart pugged into the power of my house, I was driving up to my house and the radio in my car started squeal, the closer I got to my driveway the worse it got, I pulled up next to the room it was in and it was really squealing bad. I pulled the smp wall wart from the mains and the noise from my car radio stopped.
It was using the whole houses wiring as a transmitting antenna for it's rf rubbish to contaminate anything close by.

I say ban all smp's and Class D amps.

Cheers George