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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
1,093 posts
 
Hi atmasphere,
     Thank you for your explanation.  I know your credentials and trust your comments have no hidden agenda.  Unfortunately, I don't know georgehifi's credentials and whether he has a hidden agenda against class D.
     Okay, so you're stating that there can be intermodulations between the scan frequency and the signal being amplified in class D amps.  Amp designers call this 'inharmonic distortion' and its affects may be a cold and sterile sound.  I just have a couple questions about this:

1.  Is there a consensus among amp designers that current switching frequencies (what I believe you're calling 'scan frequencies') being too low is the primary cause of 'inharmonic distortion'? If so, is there also a consensus that raising switching frequencies to the 3-5 MHz range would reduce 'inharmonic distortion'?

2.  Can you explain why I, and apparently many other class D amp users, do not perceive our class D amps as being cold or sterile?  Do you think the ability to perceive  the affects of 'inharmonic distortion' differs among individuals or do you think it's more likely the degree of 'inharmonic distortion' varies by amp?

3.  Are there any current methods of measuring 'inharmonic distortion'?

Thanks.
  Tim

randy-11
1,913 posts
 
of course, you can measure all sorts of distortion products - inharmonic means non-harmonic
erik_squires
5,268 posts
 
@noble100  and @randy-11

I suggest you ignore some of these criticisms before listening. There are like a billion claims, many old or outdated or downright false.

I can tell you I cannot, blindfolded, or sighted distinguish between my current amps based on Class D and my previous, Parasound Halo A23's. The latter are linear, hi bias AB. I've also heard megabuck class A amps and mine sound as good (within their volume / power envelope).

For this reason, I completely discredit anyone who claims Class D must have x or y artifact.

Best,


E
sfseay's avatar
sfseay
167 posts
 
I am running two Class A/D Auralic Merak mono blocks and also switched from a Parasound A23.  I'm happy, but have no reasonable way to do an A/B test between the Merak's or A23 so I don't know what differences I'm hearing!  I'm getting old!
randy-11
1,913 posts
 
no worries Eric

I am going to consider an amp replacement after a DAC/disc player upgrade and anything will have to prove itself vs. my current Sunfire (which I guess is closest to a Class G or H)
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