super flower

I have Super Flower Golden Silent 500W PSU which is probably not powerful enough for my system (3900x, RX5700, rated 480W ish on most calculators), however it's supposedly a very efficient/high quality power supply and has been absolutely fine in demanding games, so I was hoping to leave...

I need to find 7 of these sockets (not the plug/DC cable side connector): Anyone know where to find them, or even better, the name of the connector?

So this is a weird one but any input will be appreciated. I'm having a repeat issue of buzzing being emitted by any PSU I stick into my desktop. I've gone through 3 Corsair RM1000x PSUs with each one emitting a buzzing sound, the first one only produced a notable buzz after two weeks (which...