Anyone have any ideas why a PVS14 would randomly starting making a sound only when it turns on? Lasts about 1 second. It is not consistent noise, and is not like a NV whine, I've heard others describe. Any thoughts appreciated. Thanks!
I have a 14 that I bought from tnvc back in 2016. It has always made a low pitched hum for about a second when I turn it on. The "nv whine" AFAIK, is a Hollywood/video game thing. I don't have much experience with other systems though.
Even today, some NV power supplies whine when on. It's /very/ quiet, cannot be heard by anyone not using the unit so is not a problem, and like tube flaws, you get used to it (I had to borrow one of those for a weekend once) so it doesn't annoy or drown out other sounds).
A few more also do the same whine at power up. I am not an electrical engineer so while I have had it explained to me why some power supplies make noise I never remember why. As far as I know, it's not indicative of the unit failing or anything, just is how it's built. I /assume/ there's a good reason they aren't all totally silent now, and it's not just cheapness or old tech as by no means are the "noisy" ones I have encountered consistently cheap, foreign, or old.
Do you mean not constant or a different type of noise? If so, what IS it like? Aside from cap charging sorts of sounds, I've also heard a variety of snaps and clicks as microrelays (I assume) do their jobs.
Many modern era thermals also click to change the aperature just every once in a while, and since it's irregular, it can be annoying or even — when waiting in a stressy and silent area — a bit startling.