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Should I steer clear of class D amps

I’m finally upgrading my amp. I currently have an Onkyo TXNR 636 which has served very well but it’s now the weakest component in my system.

I’ve a budget of up to £1200-£1300 and been looking at the NAD C3050.

I was initially drawn to the NAD C3050 when I saw the VU meters but these are not deal breakers if I can get a much better amp without them, but I really do like them. I spoke with a dealer and he mentioned all NAD amplifiers are now class D and that’s now where I’m stuck procrastinating my purchase. My understanding was class D never really took off, despite the power efficiency due to the HF noise caused by the PWM. Times change things improve but I can’t find much about how they have mitigated this, in fact an article in EETimes refers to how the tests performed for THD etc are quite irrelevant in a digital amp and quoted figures may be very different in real life. In essence, the way of testing makes them look better than they are. This may be true but do they sound good? We all know vinyl is technically an inferior medium but I certainly prefer it’s sound.

I am listening to classic/ heavy rock and a mixture of lossless streaming from a NAS into a Cambridge Audio CNX V2 and vinyl off a Technics 1500C with a Pro-Ject DS phono stage all into monitor audio bronze 5s. 
 

I need a new amp. I need slapping out of my indecision but it’s not an insignificant amount of £££ and I want to get it right. Should I stick with AB ? My electric bill can’t withstand class A or valve regardless of sound quality. 

Also what’s the thoughts on NAD in general, I’m my youth they were good amps, but then so were Pioneer. 
 

nosleeptilldownload

Showing 2 responses by atmasphere

atmasphere's avatar
atmasphere
11,615 posts
 

Class D amps need a tube preamp or a solid state Class A input stage that adds 2nd order harmonic distortion to the signal. Linear power supplies can also add 2nd order harmonic distortion. 

These statements are false. I can imagine some amps (regardless of class of operation) for which adding a tube preamp or the like is the band-aid needed for their dryness. But if the amplifier is properly designed it needs nothing of the sort. The second statement is just- wrong.

atmasphere's avatar
atmasphere
11,615 posts
 

My understanding was class D never really took off, despite the power efficiency due to the HF noise caused by the PWM. Times change things improve but I can’t find much about how they have mitigated this, in fact an article in EETimes refers to how the tests performed for THD etc are quite irrelevant in a digital amp and quoted figures may be very different in real life. In essence, the way of testing makes them look better than they are. This may be true but do they sound good? We all know vinyl is technically an inferior medium but I certainly prefer it’s sound.

@nosleeptilldownload Your impression above is incorrect. Class D really took off and is used nearly everywhere.

What makes an amplifier musical or not is its distortion and nothing else! Literally the distortion signature of any amplifier is also its ’sonic signature’. The trick to getting an amplifier to sound musical (for example many tube amplifiers) is to have a benign distortion signature which the ear does not find irritating.

Since this is all about understanding that fact and also engineering, its possible to build an amp that will sound like music if you have the expertise.

Cutting to the bottom line there are class D amps out there that sound every bit as musical as the best class A tube or solid state amps. Because you’ve not heard an example of that yet does not mean they do not exist! IME class D amps vary as much in sound as tube amps do- from the worst to the very best.

I’ve been playing a set of class D amps in my own system the last 2 years and do not miss the class A triode tube amps they replaced at all.

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