To clarify, I have a Clearaudio turntable with a 12v DC motor. Clearaudio indicates that their DC power supply is voltage stabilized, yet they sell a separate 12v battery power supply. This suggests the stock power supply has some limitations.
To me it suggests they can sell it and make money. Expectation of performance is almost as good of a consumer motivator as validated performance.
The operating range on the ClearAudio AC supply makes it sound like a switcher? That is not inherently bad. It will mean it will handle your 113V or pretty much anything you throw at it without too much issue. Depending on how it is designed, the output voltage may be totally independent of the input, or slight variation. The turntable also has active speed control based on a speed sensor, so that is ultimately setting the speed, and will also adjust up and down as needed. I don't think you would see any variation in turntable speed if you tried to measure it. Not even a tiny bit. You would need a wow and flutter meter. Realistically, the bearing are causing more speed variation, not to mention non perfect placement of the record hole, etc. etc.
I would be far more concerned about just general "noise" which you seem to have addressed at some level. Maybe you can borrow a power regenerator and see if it meets your needs.