Hypex N core module

noble100 -

You wrote,  "the thought struck me that this poor performance may be a result of a very revealing amp combined with poorly engineered and/or poorly recorded source material."

I agree, in my experience the better your system, the more revealing it is of bad recordings. And many, if not most recordings are pretty bad.

My speakers are 4-way hybrids - two 15" dipole bass cabs + mid-horns + bullet horns per side, DSP'd by DEQX processors and powered by eight modified NuForce Class-D amps. My system is accurate and very revealing of poor recordings.

Some of my favorite records sound  pretty bad on my system, in the same way that low-definition movies look sub-par on a high-definition front-projection video system - low def video looks better on low-def TVs. And low-def recordings sound better on lo-def systems.

With excellent hi-def recordings my system shines. No problems with tone or anything else.

I tried using a Yamamoto se45 amp on the horns, and a Pass Labs Aleph, and MacIntosh and Marantz and Fisher tube amps - all were outperformed by my Class D amps.

By the way, I would buy eight Mola Molas or similar if I could afford them - and if they sounded noticeably better than my hot-rodded NuForce I would be surprised.

I really liked my NAD Masters M22 which was based Ncore and most agreed sounded much better than the standard hypex kits, until I did numerous A/B tests in a highly damped room, with reference electronics and Focal Sopra 2's.  The NAD was rendered dry, sterile, and lifeless compared to the good Class AB amps, which was pretty disappointing considering I owned it.

YMMV but I won't be going back to Class D anytime soon after that experience.

i now have a Perla Audio Signature 50 integrated that blows the NAD away in everything but sheer power.

I had followed these class D discussions for a while and wanted badly to try them in my system! I had one of the best class A power amp(Pass Labs) and really like it but size, weight and heat were factors that pushed me for class D! I got Hypex Ncore 500 and for the first time can hear the differences! Ncore is more accurate to PL (might be because I bought PL as 2nd hand and it was old) Ncore has better control on bass and easy to drive any speaker but it is not as musical as PL to my ears specially on low volume ! Long story short, a good class D is amazing for newbies and ppl that don't consider themselves as an audiophile!     

     My opinion is that, for a thread that just asked if anyone had experience with Hypex class D amps, the numerous responses have instead provided a wealth of useful information from individuals that have experience with class D amps in general which has expanded the discussion well beyond just Hypex based amps and arguably was more informative to anyone considering a good class D amp. 
     I've enjoyed the discussion thus far and hope the OP, bache, feels the same even though the responses have expanded beyond his specific question. 
     The responses have been wide ranging, from class D is only good enough for subs, to class D is good but I think my class A or expensive class A/B or tube amp is better  to class D is very good and I sold my old amps.  I think these are all valid responses that are accurate and truthful with the exception of the first one.
     This thread has reinforced my opinion that exceptionally good system performance can be achieved with the use of the better class A, class A/B, tubed and class D amps.  I think the biggest benefit of class D is its efficiency and many might prefer an alternative sound for their systems. 
     I believe the better class D amps are so accurate and neutral that they may not be the proper amp for those who prefer a touch of flavor to their system sound that some of the better traditional amps possess.
     I understand the appeal of high quality traditional amps and would likely own one if my budget was higher. I like that everybody's system can be as unique as a snowflake and tailored to their preferences.

   Tim

Gentlemen,
If I may provide a designers perspective. I don't want to wade into a he said, she said. I am just providing my design experience.

Class D is going through a maturation stage and developing fast. The prior lack of experience in higher frequencies, above 20kHz, of Audio designers has led to some bad class D designs, while non-audiophiles have entered the market with good designs but bad Audio sound.

Audio sound, aside from being subjective (tubes vs SS), requires real time application and the human ear is very sensitive to sounds not just in the Audio range but outside it as well. Combined they make up the sound. The staging, "air" etc is also made up for many aspects that are not generally measure by Audio designers and manufacturers.

So with that Preamble.
Class D has suffered from lack of high frequency knowledge - designing traces that interacted with each other, designing power supplies that don't have kickback or noise, designing layouts that don't propagate RF, Capacitance in the MOSFETS that  don't allow fast switching (that is turning off from on, and on from off - this is not the switching frequency but speed on which it can respond),  Inductance of the MOSFETS cases, timing of the deadtime vs switch time and so on. While it is not very complex, Class D requires a lot more knowledge AND design then a Class A or Class B or a tube amp, only because there are a lot more complexities to be considered.

A good Class D will keep the dead time to a minimum, reduce interactions between traces and power supply ( overshoot, ring) and have a clean power supply so you don't hear it.   The amp boards and Power supply boards (Switching power supplies) are very sensitive to placement, wiring, components and so on.

Hence just making a amp board that sounds good is not enough. The whole amplifier has to be engineered. Switching frequency, theoretically is nice to have higher, does not work well with MOSFETS, as the capacitance in MOSFETS don't allow for a fast(er) turn off/on. 

The filters can be as clean or as horrible as the designer makes it to be. Having a sharp filter on paper with lossy components makes for bad sound as lossy components have a lot of parasitic impedance and will change the whole curve and filter.

Finally the Class D amps are of age where they can be superior to any other class available today - it just takes good design. Class D has many benefits that you cannot get from the other types of amps, including better sound. 

BUT as all things, there are no absolutes. It must be better design, better built, better implemented, better engineered to be better. Just saying Class D is better or worse does not make any sense as saying Tubes or SS is better then the other.

Hope that helps a bit with the understanding of Class D