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Class D = Trash?

So, I'm on my second class D amp. The first one, a Teac AI-301DA which claimed to use an ICE module, was unlistenable trash. I burned it in for a few weeks, it just couldn't perform, so I sent it back. Following that, I tried the new Emotiva A-300 (class A/B). It was significantly better, but lacking in too many ways for my tastes. So I changed gears, got an 845 SET from China -- and it was an immediate and massive improvement.

So, before I went further down the SET road, I wanted to try a better class D product using a modern class D module. I settled on the D-Sonic M3-800S with the Pascal module and custom input stage. I read from reviews that these things like to have big cables, so I picked up an eBay 8 gauge power cable (Maze Audio, el-cheapo Oyaide copy plugs, braided 4-wire cable) to go along with it.

Mid-range GONE.
Soundstage depth CRUSHED.
Euphonics DISAPPEARED.

Yes, resolution went up. Driver control went up, allowing me to play compressed rock/pop and orchestra with the speakers being able to render it all. But enjoyment in the sound is basically gone. Using my best power cable (LessLoss Original) improved performance, but didn't fundamentally change the amp's nature. I ran back to my headphones (Focal Utopias) to detox my ear canals.

So, how long does a class D need to burn-in? I want to give it a fair shake before writing the technology off forever. 
madavid0
noble100's avatar
noble100
2,419 posts
 
Hi atmasphere,

     Proprietary power modules and supply?  Wow!  Very cool and very interesting.


Good luck,
   Tim
georgehifi's avatar
georgehifi
10,312 posts
 
seanheis1
  I started a thread about it and it appears that the switching frequencies aren't currently high enough to avoid degrading the signal. If it was a simple break in issue, they would be broken in at the factory.

Don't give up on Class D though. When the switching frequencies improve, they will become the solid state amps of choice. Some folks don't hear what we hear and they are fortunate to enjoy these small and efficient power houses. More power to them.

Well said the day will come with much higher switching frequencies, as I also posted to Randy's question
randy-11I always thought the gentle filter slope was b/c steep "brick wall" filtering caused caused audible distortions...


It’s because a simple low order output filter can take the amps full power, but it’s effects reach down into the audio band and still leave some switching noise left overs, hence the need to take it up much higher as Technics did with far higher switching frequencies, so they can be effectively removed, without effecting the audio band.

These days when Stereophile tests a Class-d amp, they put on an external output filter, the Audio Precision’s AP0025 filter, which has a -50db rolloff after the audio band so the 1khz square waves look half decent without the switching noise embedded right across it, (good for sales) 10khz square wave still looks a mangled mess though, trouble is this AP filter can only take very low power, would be real nice to leave it in to listen to, but it would blow up in a micro second.

http://www.stereophile.com/content/class%C3%A9-sigma-2200i-integrated-amplifier-measurements#31YFAPfYVDGeowzZ.97  
And yes steeper filters as you said do have their own set of problems re sound, as ML found out with their No.53 monoblocks.

Cheers George 
sfseay's avatar
sfseay
495 posts
 
Anybody here running or have auditioned Auralic Merak monoblocks?  Just purchased a couple and should be arriving today.  Moving to these from a Parasound Halo A23
Post removed 
georgehifi's avatar
georgehifi
10,312 posts
 
May not be trash for long madavid0.


Class-D that can finally equal or better hi-end linear amplifiers, tube or S/S.

 It's closer than you think.

Why We'll Soon Be Living In A Class D World 

"In fact, that transistor technology is available today and is increasingly being used by manufacturers to create near perfect sound quality for Class D audio systems. The greater switching speed of Efficient Power Conversion's (EPC's) eGaN® FETs allow amplifier designers to increase PWM switching frequencies, reduce dead-time, and drastically reduce feedback; in turn, producing a sound quality previously limited to large, complex, heavy Class A amplifier systems. Further, this innovative high-speed switching technology has already disrupted myriad other industries, including telecommunications, medical, and automotive to name a few.  
A high-definition eGaN FET-based system with higher PWM switching frequency, reduced feedback, and higher bandwidth produces the sound that has the warmth and sonic quality that audiophiles demand; while actually improving upon the power efficiency of traditional Class D. Class A audio's historic lesser child Class D is coming of age with eGaN technology. And in the next decade, these systems will replace Class A technology, as well as the silicon MOSFET Class D systems in active use today. 

Significantly, audio manufacturers are taking notice and incorporating GaN-based Class D FETs in their systems. This is why, in another two or three years you will start seeing a slew of new Class D amps - ones based on GaN - rolling out to the market; and, for such varied uses as home theatre, car, boat, portable wireless speakers, along with high-fidelity home systems."  


Cheers George
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