Hypex N core module

At the risk of making the least contribution to this thread and over generalizing the discussion, my somewhat limited experience with hearing class D amps at various shows and friend's homes has had one thing in common. That quality, almost irrespective of the downstream or upstream gear, was that I always felt I was listening to the instruments as opposed to the music as a whole. Whether its the ultra revealing nature of the technology or the choice of the associated gear, I can't tell but I was consistently blown away by the sound for the first few minutes followed with my brain going into overload with the amount of detail I was hearing and ultimately felt exhausted with the demand. Some may consider this experience the holy grail of audiophilia but for me it felt like I was watching the trees as opposed to enjoying the forest scenery. Perhaps crude analogy but the best I can do.

Class D amps are very sensitive to power i.e.

 Yes they have one of the most dirtiest power supplies made, SMP's
That's why you'll see many caring Class-D manufacturers giving them more quieter linear supplies, just to null out one of the problems of Class-D amplification.

Cheers George 

"Bruno is spot on with this. The usual rule of thumb is that very low amounts (under 4 db or so) is not harmful, but more than that is a problem; after about 20 db or so things start to settle down. 60db hasn't been practical until the introduction of class D (since gain is developed in an entirely different way); so I have no argument with this; my prior comments should be limited to traditional amps where making the kind of gain is impractical."

Thanks, Ralph. Your statement has cleared this issue up for me.

darknightdk,
     Although I use more mid-level class D amps than your Acoustic Imagery Atsah mono-blocks, your described impressions of your class D amps as "being extremely revealing, neutral and transparent and will take on the character of the source equipment, cables and material being played" closely resemble my impressions of my amps. Like you, I've been amazed how clearly audible the performance level of upstream components, cabling, power cords and recordings can be heard and judged as well as how clearly audible the affects of any changes to any of these can be heard and judged. The best description I can think of is the proverbial 'straight wire with gain'.

     This level of clarity and detail is not for everyone and any upstream weak links in your system will definitely be exposed.  I prefer this honest quality in my system rather than a masking or inaudibility of weak links; weak links can always be upgraded in quality but only if you're aware they exist.

Enjoy,
  Tim

" First you need a bit more clarification on just what "feedback" are you talking about, "global feedback" or Local feedback"? As both are very different.
"local" is a good thing if the output stage is designed right with minimum problems. "Global" is also ok if used sparingly and not use to correct big problems."

georgehifi,

     According to Bruno Putzeys, 
    "Local feedback with a bit of global feedback is, actually, identical to full global feedback -- mathematical fact."  
      I believe he utilizes this approach in his class D designs.  He also believes there is no such thing as 'too much feedback' as it pertains to class D amps.

Tim

 "Local feedback with a bit of global feedback is, actually, identical to full global feedback -- mathematical fact."  

You can have local without global, this is preferable in linear solid state, if the output stage is well designed you can do without the global and just have local around the input and driving stages, many good hi-end amps do this and it sounds much better for it, Gryphon, ME, Krell  ect.

He also believes there is no such thing as 'too much feedback' as it pertains to class D amps

That's his opinion, not by many noted others. And it looks like Ralph's going minimal FB as well.
Large amounts of global feedback used in linear amps is used in poor designs, to get good specs, the challenge is to get good specs with only a little local feedback.
 
Cheers George