@JTBrown That is moving to the other extreme, in which the power supply's feedback loop probably has time to catch up and keep the voltage constant. If the supply has enough oomph, it may be ok. The observed behavior, though, was a sign you might be near the edge. The other possibility is that the supply is badly designed, so the low-frequency behavior of the regulation doesn't cross over nicely with the filtering of the capacitance. Incidentally, I had this problem, exhibited differently, and very annoyingly. For many months, all the LED lights in my house flickered annoyingly. It took a long time to associate it with the 3d printer. Somehow, the PWM frequency for the bed, which I had at one point set to 30 Hz, had gotten trampled back to the default 10 Hz. It takes only a tiny bit of line voltage variation at 10 Hz to crate enough flicker for the eye to see. It's pretty much at the top of the frequency response. So the whole house line voltage was being microscopically modulated, resulting in a drool-inducing flicker.
