Comments on Profile Post by GoldfishX

Is your system on the same line as the light? (Check fuse box?) Perhaps switching the bulb would help, like a LED one?

It's a large overhead kitchen bulb. I can't get to it because of the covering. Older complex, so LED is unlikely. My guess is the wiring is completely hidden, so it messes with the other outlets when it's on. But the music dynamics are completely gone with it on (I A/B'ed it earlier). I'm rocking my test playlist now, while stress-testing the PC (plugged into different outlet on same wall) and it sounds great.

Get the music on a different circuit. Yes, for me, even a postage scale (with its tiny wall wart just plugged in) on the same circuit can shrink the soundstage, noticably. Every home is different and some are way better than others. Keeping the music equip on a circuit without a lot of other stuff can be best.

Come to think of it, I DID notice a difference from a laptop charger plugged in but I'm not hearing a difference from the gaming PC (same outlet). 90 watts vs 750watts. Hmm! I really am trying to get one whole room to music/non-electronics and the other to all other electronics (gaming/PC/home theater).

This laptop switchers can be loud. Your PC rig power supply may be a quiet toroidal unit with filters. And you’re probably buffering that with UPS or isolators?

Maybe you can try a DC blocker and RFI filter? I'm building one of these https://www.atlhifi.com/shop/bare-pcb/pcb-for-dc-trap-blocker-and-emi-rfi-cm-filter/ Though they have ready made ones and there are other alternatives.

Older light fixtures? good chance it's a fluorescent with a nasty ballast inside which is like the angry caveman cousin of a switch mode power supply.

I'd say that a PC, however beefy, is well shielded from things around it.

Nothing in it works direct from mains. Do PC PSUs provide some measure of isolation? Never thought about it but I suspect they might.