Related to remembering sound: I borrowed my dealer’s Isotek so-called Mains Noise Analyzer for giggles.
First of all, the “results” of this are entirely unhelpful. I plugged it into various sockets around the apartment and sometimes it displayed higher noise numbers (it goes from 0 = “no mains noise” to 1000 = max) and emitted a louder sound (which it does to signify the number reading (and, I suppose, to scare one into investing into an Isotek isolation device)), sometimes it was low.
In the living room, I had very clean readings (~50) from the hifi socket when I plugged both my laptop and a NUC into other sockets (on different circuits in the same room). Noise readings went to maximum when I unplugged these polluters. Then I tried the bathroom and in one socket the noise was nearly zero. But then I realized that I had plugged the “analyzer” into a little 1-to-3 socket multiplier that I had bought on Amazon for 2 euros. When I plugged the “analyzer” directly into the socket, noise was maxed out again.
So, more related to this thread, I tried the hifi with the laptop and NUC plugged into their sockets (supposed low noise), and then without. Then I ran a heavy-gauge extension cord to the bathroom and tried as well with and without the socket multiplier.
With the laptop and NUC, all it took was to get up from couch, make 2 steps, plug/unplug the laptop/NUC, fall back on couch. Even with this little distraction, I could not be sure. Sometimes I thought something changed. Then I was convinced that it hadn’t. Occasionally I was confused about the current laptop/NUC state and thought the sound was indeed better with them plugged in (supposed lower noise readings), only to then realize that they were actually unplugged.
Comparing the bathroom socket to my regular hifi socket required, of course, system shutdown and restart, which takes a minute or more until NDX2 and 252 are working again, and predictably I had even less of an idea.
After much back and forth, I concluded that either there were no SQ changes at all, or they were small, seemingly random, and unrelated to the sockets and noise readings.
Now, I don’t rule out that I am particularly unsuited to this kind of comparisons, but the evidence certainly did only one thing, add even more support to the established evidence that our ears are not objective and our brain sucks at remembering hifi SQ.
What’s great was that after I stopped dicking around and listened to the music, the system sounded just as fabulous as always and very enjoyable.