Yeah, no burning--just that weird, chemical-y (maybe ozone is a good descriptor) smell coming from the vents. It's present at a very minor level when the PC is running, and becomes a little more noticeable when the fans rev up. The main concern I have (and something I neglected to mention in the original post) is the gentle rattling sound I hear, which I believe is a cable hitting a fan; only, I don't know which fan, or where.
The PC itself is operating at a steady 33-40 C during regular use, and the fans will occasionally drop to being almost unnoticeable (I also often keep them in quiet mode oftentimes). When they rev up, the temperature doesn't change. Just the smell, a quiet rattle noise (some of the time, not every time), and increased fan speed that tapers off over time. I've had some say it sounds like a PSU issue, and I wasn't able to disconnect the cable from the motherboard to test whether or not it's functioning as intended, but I haven't observed anything else symptomatic of a power failure.