Class D Technology

THD numbers, while appearing to be unusually good, may be partly the result of using too much negative feedback. I’ve never heard this amp, but too much negative feedback and you can end up with a soulless amp.

You’ve got that right, anyone who’s had an amp that’s had feedback level control, knows that too much can lead to worse sound, minium is best if you can keep the bass tight extended. I put them on all my tube amps that I made, to do it on s/s can be dangerous.

Cheers George

     I've read about all this supposed noise produced by my class D monos due to their SMPS rather than a typical analog power supply and all the noise produced in the audible band due to their switching frequency being too low. However, the only noise I can actually hear is from claims of all this class D noise  that no one can hear.  
     I'm no scientist but I understand the difference between theoretical noise and actual verifiable noise and that, empirically, only the actual noise can actually be heard. by us humans.  Noise needs to be heard to exist.  
     In my experience, and apparently many others experience, class D amp noise is being exposed as a myth. I have yet to hear from any class D amp listener or user hearing any noise issues.  In fact, I have yet to hear any descriptions of how this theoretical noise would audibly manifest itself.  

   I'm trying to keep an open mind but I'm not going to believe in dragons without at least 1 charred sheep or human.


Tim 
    

     

Hi Tim, I believe someone explained it best when they said that there were two ways that amp makers deal with the noise produced in the audible band due to the switching frequency being too low. One way creates an overly smooth top end with missing detail and the other way creates a hard sound. Either way, both are forms of distortion. 

Noise needs to be heard to exist

Not correct, EG: take an opamp for instance, it can oscillate (if not implemented well) at VHF, too high to hear, but it will make a known opamp with smooth sound, sound hard/bright because of the oscillation that you can’t hear.
And if the noise is filtered out afterwards then the opamp is compromised and can sound too bland, better off not having the oscillation to start with in the first place.

Cheers George

Question:
     If a tree falls in the forest, but no one was there to hear it, does it still make a sound?

Answer: 
     Yes, the theory being the tree hitting the ground moved the air and created the sound.  Because  someone was not there to hear this sound does not mean the sound did not exist.

Question:
     If a class D amp is playing in a system, but no one could hear anything other than finely reproduced music, does noise still exist?

Answer:
     Who cares, although there are theories that state the SMPS and a low switching frequency has affects on the sound in the audible band,  no human has ever claimed to hear these affects or even describe what these affects would sound like.

Thought this might be helpful,
     Tim