Time to buy a class D amp?

Hello niodari,

     Amen, brother.  I don't believe any class D amp user or fan is claiming they absolutely are the best overall amp type, that they sound the best, reproduce a certain frequency range the best  or are the best amp for everyone. 
     Personally, I'm just claiming in absolute terms that class D amps are the quietest amp type, are the most electrically efficient amp type, are the coolest running amp type and are typically the smallest and lightest type.  In more subjective and relative terms, I personally claim that good quality class D amps offer very good overall sound quality from top to bottom, are generally and relatively more affordable than other amp types and, therefore, are generally better bargains than other amp types.
     Of course, I realize our choice of which amp to purchase is a subjective one based on more than just personal preference and budget.  The truth is I don't actually give a hoot which amp type individuals choose to purchase.  I'm absolutely certain that I get more pleasure listening to my class D amp than I would ever get from convincing anyone else to use a class D amp.
     My main intent, based on my personal experience, is usually just spreading the word that class D amps were a very good choice in my system with my inefficient Magnepan speakers.   My expectation is that some individuals will find my comments useful, some will be offended and most won't give a sh$t.

Tim

  noble100 "Oh, and just to guarantee fairness and honesty, it is stipulated that your failure to respond on this thread will be an admission that class D amps have the highest Signal to Noise Ratios of all the amp types and, therefore, can be scientifically declared as the quietest amp type. "

Well here you have my little response to you're "stipulation" of "facts" and demand that I share with you research again that I have already provided and that you have dismissed, ignored, or refuted based on your deeply held cherished beliefs.

Hello clearthink,

     I was expecting a list of amp types with their SNR specs ranked from highest SNR to lowest.
     But there's really no reason for you to respond,  I think everyone reading this thread understands by now that class D amps are the quietest amp type.

Thanks,
  Tim 

I too, would be interested in your evidence to back up this claim. Of course there are low end class-D amps, i.e. cell phones, low end car stereos, etc. that are "noisy", but in general, class-D and variants of it are very low noise, and if direct digital, very low noise. This is not surprising since it is inherent in their operation. They don't suffer from amplified flicker noise, amplified Schott noise, etc. in the same way that traditional amplifiers do.

I am curious as to what measurement devices you used. Can you provide the make / model and perhaps what firmware version you were using at the time?



clearthink914 posts10-21-2019 2:16pmnoble100"Anyone who claims class D amps are noisy has obviously never listened to one"

This is wholly, completely, and utterly false, speculative, and prejudiced not only have some of us "listened' we have also actually "measured" using reliable, repeatable, objective measurement techniques that are recognized by engineers, scientists, and industry as fitting, proper, and appropriate but of course if you are happy with Class D you should absolutely enjoy it but you're reasoning, arguments, and suspicions are unfounded and false.

This is wholly, completely, and utterly false, speculative, and prejudiced not only have some of us "listened' we have also actually "measured" using reliable, repeatable, objective measurement techniques that are recognized by engineers, scientists, and industry as fitting, proper, and appropriate but of course if you are happy with Class D you should absolutely enjoy it but you're reasoning, arguments, and suspicions are unfounded and false.

Wow. Because of the unqualified way in which this is stated, it renders the statement false.

I have a little Topping class D amp that makes 30 watts per channel. It has a lower signal to noise ratio than a Realistic SA-175 amp (despite the fact that the Realistic only makes 10 watts) we have in the shop that is rebuilt (being nearly 50 years old). In case anyone is wondering why I have an old Realistic amplifier hanging around, I put myself through college working at the regional Radio Shack repair center in the Twin Cities, and I enjoy troubleshooting and rebuilding work as a hobby; this amp is definitely a bit of nostalgia and its cute.  I rebuilt the matching tuner too.

In our work the main thing that we've seen that contributes to noise in a class D has to do with the encoding scheme- in our case, Pulse Width Modulation (PWM). PWM relies on the use of a triangle wave generator and a comparitor that compares the incoming audio signal to the triangle wave and thus has an output that is either on or off. If the triangle wave generator is not perfectly steady in its frequency, or if there is a bit of DC offset at the input of the comparitor, the result can be a bit of white noise hiss in the loudspeaker. With fairly simple techniques this noise can be reduced to noise floors that are less than conventional amplifiers.