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Filtering out distortion in a sine wave

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I'm seeking a circuit for a 60Hz sine wave generator, to make a low-distortion turntable power source. There doesn't seem to be very much that is practical with a distortion under one percent.

But riddle me this: The signal generator cards on ebay, using obsolete function generator chips, say that they can do it if I have a distortion analyzer to guide me in trimming the output. Well, I don't think I'm ready to go out and buy a distortion analyzer, and Home Depot doesn't rent them.

But if I use an ebay card the way it comes, with maybe 1.5 or 2 percent distortion, and follow it with an opamp 12db lowpass filter set for 60 Hz, that kinda means the filter will attenuate the harmonics, right? And harmonics is what harmonic distortion is, right?
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Follow Ups:

RE: Filtering out distortion in a sine wave - andyr 21:36:05 07/05/25 (0)
" And harmonics is what harmonic distortion is, right ?"

Good question - as I actually don't know the complete answer.

What you need for your TT power source is a nice, smooth, 60Hz sine wave, right. We can call this an "undistorted" sine wave.

On a CRO screen, this looks like a thin (sine) wave.

Whereas a "fuzzy" sine wave looks like a thick line on the CRO screen. This is what your actual mains feed looks like.

But I would think this 'fuzz' is not caused by harmonics of the base 60Hz sine wave; it's due to something else entirely.

So I wouldn't call it a " sine wave with added harmonic distortion ". I would call it a "dirty sine wave"!
RE: Filtering out distortion in a sine wave - Tre' 18:49:02 03/06/25 (0)
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RE: Filtering out distortion in a sine wave - David McGown 18:40:51 03/06/25 (0)
A crazy idea, why don't you record 45 minutes of a 60 hz sine wave using software like Audacity saved to a WAV file at 16 bit resolution and play it back through a portable player/DAC as input to a motor drive amplifier. It will be an extremely low distortion signal. An old iPod or similar player would do the job. Even a CD player playing a CDR would work. You could record several waveforms each at a slightly different frequency if you wanted to vary the speed. I considered doing this when I was using a Tascam/ Papst capstan motor as an alternative to a problematic DC motor for my Teres turntable. Of course a typical AC motor is two phase (sine/cosine I believe) you actually need two driving signals, since the phase lag capacitor only approximates what the motor needs for smooth operation. One might need to play with the phase angle for the smoothest operation. The Papst motor I was using is actually a 3 phase motor, so the smoothest operation would be using 3 sine waves 120 degrees apart in phase angle. In the end I opted for a different DC drive solution (a Maxon motor drive controller).

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