Would I be wasting my money to get a turntable?

@bigtwin much more concise :)

Talk about diminishing returns…

Cheers 

What happens when your PWM’s oscillator signal frequency is not high enough?

This frequency, likely >0.5MHz limits amp's bandwidth.  My older Icepower was limited to 60kHz, resulting in 20deg phase delay at 20kHz.  It can affect summing of the highest harmonics (that I cannot hear anyway).  Zobel network on the output leaves about 1% of the ripple, but the membranes at this frequency don't move.  This 0.5MHz frequency is about 100 times higher than highest root frequency in music resulting in practically unlimited resolution.  I agree, there are limitations of class D, like of any other class - I was just stressing, that the fact of switching output between two voltage values doesn't make it digital since these constant voltages are not the quantity of interest at this point (duty cycle is).

Couldn't have said it better myself!

Because I have no clue what you're talking about.