Would I be wasting my money to get a turntable?

@gregm +1 - I should have been more explicit! 

I think the key question here is 'what would you listen to on the turntable?', rather than 'can it sound good?'

The answer to the second question is yes, provided you choose a good turntable and set it up well. Would you get an improvement in sound quality vs. a good digital streaming source, properly set up? IMHO, no, but to some extent 'sound quality' is subjective.

The basic answer is ’energy efficiency’ - by converting the (voltage amplified) signal into a PWM (or other modulation technique) signal, and then filtering that PWM to retrieve the audio signal, the transistors in the final stage are always ’open’ or ’closed’, thus dissipating minimal energy.

Note that in many power amps the analogue-to-digital conversion happens only at the final power stage, which is where ’traditional’ amps consume most energy, however the NAD seems to convert phono signals to digital earlier than that.

@glennewdick 

One class D is not digital in anyway

What do you call the conversion of an analogue signal to a PWM/PDM or ΔΣ modulation and its subsequent filtering to recover an amplified analogue signal? Because if that’s not digital, then CD is not digital and streaming is not digital either. However, that’s exactly what happens in a class-D amp, at some point. The filtering is at the very end, but the signal conversion can happen at the amp input or just before the final (current) amplification stage.

@carlsbad2 Tell us more.

@glennewdick

there is no digital (I.e. code) in a class D amp, period. your confusing the differences here.

I’m sorry, but the one who is confused is you. The technique used in class D (which I agree does not stand for ’Digital’) is the same PWM (or other pulse-based modulation) used to convert an analogue signal into a digital stream for CD or other digital medium and back into an analogue format. Neither more, nor less. If there are ’digital sound quality’ issues due to quantization or filtering, they would emerge in this transformation neither more nor less than in an ADC converting an analogue signal.

The fact that potentially the only operation performed on the pulse stream so obtained in a class D amp is amplification, and it is not treating the digital stream in other ways, is neither here nor there: they are 1s and 0s whether you like it or not: the transistor is either saturated or cut-off, and in fact any use in the linear zone is not only not-favoured; it is discouraged and unwanted. The analogue signal is not recoverable unless you use the same techniques to demodulate and filter the pulse stream that are used in a DAC (obviously with much higher currents and voltages, but again that is irrelevant).

I’d suggest you get a degree in EE, then perhaps we can google together from the same basis of understanding.