most record players will be slightly out from each other, but might not be audible because the whole recording is out of time/pitch together, but when you add the outside element it's affected because the speed affects the pitch.
it's better to play along to CD's, plus there is so much stuff available that you can work with doing it this way, backing tracks, lessons etc
also, bear in mind that when you learn a song in standard tuning, the original album recording might have been recorded a semitone or full tone lower.
i'e, i learned welcome to the jungle by guns & roses a few years ago, but when i tried to play along to the album song it was out of key because the instruments on the recording were tuned a bit lower, also happens a lot with thin lizzy.
if you must play along to records, then you could look into getting a "speed box" from pro-ject (or similar device), these are made to control the speed of the motor to exact pitch, and stop the need to keep removing the platter and switching the belt position, all you need to do is press the button, holding it down switches off the motor bypassing the awkwardly placed power switch.
not sure if they work with all players, others on here will know
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