Measurably, there is a difference of a new record when played once, or cleaned with ultrasonics. Something is worn or cleaned off, most likely from pressing.It is actually more difficult than that.
We were once experimenting to see if demagnetizing an LP would change the sound. Lo and behold, captures before and after showed a clearly difference in sound, subjectively and objectively! Well, it turned out this was due to wear in the LP. A brand new one sounded and measured differently on the first play vs second!!! So the de-mag had nothing to do with it.
The system is too unreliable to perform any proper AB tests on it.
HumminGuru Ultrasonic vinyl cleaner mini review
This ≈60 Hz noise mainly in one channel is still a bit strange, that disappeared after cleaning. Have not been able to trace it yet. It resembles this in a way... https://www.audiosciencereview.com/forum/index.php?threads/moerch-dp8-mini-review.55923/ Hmm...
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