The reason why Jon is asking about the purchase details, is likely so you don't try and RMA something that you bought used, without proof of purchase.
I haven't listened to the audio track, but I do believe Jon's opinion that something is hitting the fan.
If there are external (not inside the PSU) cables visibly inside the grate of the PSU fan, move them so they are not in the grate anymore.
If there aren't any visible external cables causing the issue, remove the PSU and shake it (not hard enough that accidentally throw it, but don't likely shake it either), that might move the position of the internal fan cable, which could fix the issue.
If that doesn't fix it, shine a torch through the fan grate of the PSU, and look for the fan cable. Grab something non-conductive, robust but also soft so you don't cut anything, such as a plastic card, (like the ones used for public transport cards, bank cards, licences...), and push down lightly on the PSU fan's cable.
Hopefully that works the trick.
DO NOT remove the casing of the PSU, it technically will not void your warranty in the US (Not that manufacturers or retailers will accept that for warranty anymore, which is fair IMO if about PSUs), but it will void the safety certifications the PSU has, (making it illegal, and not covered by your house and/or content insurance) and frankly, inside a PSU can be dangerous, and potentially lethal if you handle it incorrectly.
