It depends HOW the PS is designed.

Every voltage regulator need a certain load in practice. This load is just some mA and when PS have a smart design then its included in the PS otherwise it's a not professional PS.

What could happen is that when the power is switched off, the output voltage of the PS is higher as the input voltage and then the voltage regulator can be destroyed.

But again, in a professional PS that issue also have to be solved-just with a diode across the voltage regulator (in reverse direction of coarse).

So if you want to be shure, look for the schematic of the PS if you can get one, or better on the PCB if for every regulator have a diode are present and a minimal output load that's a resistor parallel to the output terminals.

Robert

800v3/218/271/8k.2/5k5s smile /5kC/DSP3200/Reviver/
TT-ELP/Graham Slee Revelation/Trinnov Altitude 32/OPPO 205
__Ayon/HB/Shunyata/Miltzow -- power cables,
__Ayon/Jungson/Miltzow --analog, Miltzow-- digital,
__Vortex/WMA ,