The specs that you provided for the wall-wart indicate it is merely a step-down transformer, not a power supply at all, thus LPS need not apply.
The turntable could have built-in power supply circuit, and it may or may not be linear. If it has such a circuit, then your turntable uses DC motor, not AC.
In any case, replacing the wall-wart with another AC adapter won't do anything for you.
The turntable could have built-in power supply circuit, and it may or may not be linear. If it has such a circuit, then your turntable uses DC motor, not AC.
In any case, replacing the wall-wart with another AC adapter won't do anything for you.