This is from HiFi Stereo Review 1978, found over on one of my favorite sites, www.WorldRadioHistory.com There's a couple tid-bits, if I find more articles on this subject I'll post more. It's so annoying, I get it with my daily boombox listening and there's no rhyme or reason, most likely some other equipment on the electric circuit.
I forget about these, my bathroom circuit is the worse and I do some of my most critical listening in there...... No seriously, the bathroom boombox radio just doesn't want a clean signal, I thought it might be the fan/light on one side, I took that apart, cleaned, disconnected it and the issue is worse! I need a gizmo that plugs into a socket and tells me everything being carried over the electrical wires.
Like the article implies, keep things simple. I would install batteries in your boombox and see if things improve (AC issue) or stay the same (interference issue).
I traced one source to a dimmer switch, but there's more. I thought getting rid of fluorescent lights and upgrading to LED would also help but I'm still chasing something.
And if you upgrade your lights to LED, you'll need to upgrade your switch to a LED dimmer. Who knows, that just might solve everything!
New ish power supplies tend to be switch mode which are inherently noisy although efficient and sometimes the cheaper ones don't bother with filtering out the noise they generate just goes right into the mains supply, get one of them intermediate voltage conditioner devices which surge protection
Yes, you should,, always try,, You know I forgot to mention surprisingly huh that you will always have some noise it's called shot noise Electrons bouncing off of things I think including each other but there are various methods to mitigate noise,, to surprisingly good effect can be minimized I had really good results with screening everything in a spider pattern back to a central earth point
I pulled it out, I was wrong, it's heavy duty plastic (Made in USA!) from Nortronics and it's only a voltage monitor & surge suppressor. Nortronics was big into replacement tape deck heads and dabbled in many other areas before being sold (and name changed) in the early 90's. I believe these were made for audio components since most of the product line also was. The wire is marked 14 guage but it feels like 10. Ultraman is wondering if you have any of that HM conditioner for his noggin?