Hi, I've bought a handmade stereo amp from my friend a while ago, and it's a decent amp. However it wasn't designed to filter out the emi coming from homeplugs (ethernet over powerline, from around 500k to 80 mhz signals). At the same time, I need a simple UPS to power my router and switch, things are next to each other and really impossible to move around. I also need to protect those devices from overvoltages. So my question is, what's better:
a) get a line interactive ups? not sure how well their filters work, if at all.
b) build a diy online ups with all the protection / filters?
c) build/get a filter, get some cheap standby/line ups, and make a small box with overvoltage and filters in it to protect the whole thing?
d) something else entirely?
bonus question (lel):
speakers get the 50hz hum too. nothing terrible, but still audible when nothing is playing. Any solutions to that perhaps? Installing a 49-51 Hz filter after the psu part? I'd probably need to check what's going on cause i had no ideas ripples can go past linear regulator chips. It's possible he didn't even put one inside even? Sigh