Thanks for the tip! I currently have the power strip inserted into a separate surge protector, which is kind of a clumsy solution.

The 6-piece Brennenstuhl seems to be on sale on Amazon de. Would you happen to know what exactly is the difference between the normal 6-piece and the "2x 3, 1 A" version?

It is, but the main difference is that unlike a modern desktop/laptop it doesn't rely on a disk drive to save its settings and doesn't constantly save things to disk. But a DAC like this saves in a more deterministic way, and has a lot less things to save, so it's likely (not 100% sure though because I don't know for sure not knowing the internals) that even if you manage to cut the power in the middle of saving it would still not corrupt settings; unlike for a PC.

Wrt electrical strain: that's something else, but I don't see how a properly designed power supply could cause harm here. I don't really know though if number of power cycles affects electronics lifetime.

If you switch your whole setup at once, a surge and overvoltage protection of any kind is mandatory.
Like the powerstrip with protection mentioned above:

https://www.amazon.de/Brennenstuhl-Prem … mp;sr=8-10
Locate it like this:
Line power outlet -> remote switch -> protected powerstrip -> audio system.

Else the counter- or back-EMF of the connected devices CAN cause higher failure rates in your system.

Can you explain this more in detail, and is this an actual issue in a 'normal' modernish audio system with decent devices (where you'd think that the devices themselves already have overvoltage protection, and if they'd be prone to producing back-EMF they'd guard against that as well)?

Also curious: the powerstrip just mentions a 10A fuse. Is that the overvoltage protection or is there more to it?

I had a problem with a special Hifi surge protector. It killed the relais of my Krell power amp twice because it needed several on-off trials in a short time to switch on the device.

This probably was an inrush current limiter, a completely different thing, technically.
If something behaves strange, better not use it.

An overvoltage protection is quasi “invisible” to the devices connected, doesn’t change their behavior and doesn’t cause such effects.

An overvoltage protection is advisable for ALL types of electronics that cost more than a few bucks.
Overvoltages come from everywhere, even outside your house:
Your neighbors washing machine, a lightning strike, your power plant ...

On top of this, your case is special and strongly asks for a protection, as a lot of devices are switched at the same time, producing high voltage spikes for sure.
Please refer to the mentioned connection order for the protection to be effective.

If the protection saved a single repair it already paid off.

And no, a fuse isn’t an overvoltage protection, it only breaks when it’s too late, just to prevent a fire (if properly dimensioned).
The 10 A fuse secures the protector from overloading current.
Overvoltage protection uses varistors and sometimes spark gaps.

Hmm, should I insert an additional residual current device in front of the surge protector power striip?

EDIT: I assume not because the 16 A fuse is apparently there to prevent electric shock (?).

Got it... This is getting expensive already, with an Intona USB Isolator on its way in the mail.

For this purpose I'm using my KVM switch. It also allows to play the music from different PCs with the connected ADI-2 Pro.

Sure, but powering it back on from another floor will be the "issue".

And regarding USB isolators... Sure, if my amp had balanced inputs, perhaps the ground loop wouldn't exist. As it stands, the PC's USB line emits a background soundtrack akin to Gremlins going berserk in the night. They even dance to the rhythm of my mouse movements!

Hardly borked. Just a ground loop that needs to be dealt with. I have the same issue in my studio and another PC (with RME AIO), except that there I can use balanced connections to fix it.

I never meant to imply it's an RME issue. I'm not expecting the input on the ADI to be galvanically isolated.

Yes, I've systematically narrowed it down to the noisy USB connection.