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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 Henry,

       You know, if I said "Hi" and used your last name after, I'd be saying:"Hi-Ho".  Mind if I say it twice and add: "it's off to work we go"?
      True story from my college days:
       I worked at a Chinese restaurant and a new guy was hired.  He was a Chinese exchange student whose 1st name was "Ho".  When he came to work the next day, I instinctively said: "Hi Ho".  After I realized how goofy that sounded, I told him his  new American name would be "Henry".  Honest.

       Okay, sorry for my side track.

      You're correct, the Abletec modules have a built-in smps, auto European/North American power sensing circuit and a regulated input power circuit.  D-Sonic also uses a custom input buffer to raise the low input impedance to 60K ohms so it's compatible with almost any preamp; so my former tube VTL preamp (output impedance of 200 ohms) matched very well with the D-Sonic M3-600 monos.

     I believe the Pascal modules also incorporate the smps and other circuits on the same board, so these are likely ruled out for your purposes as well.  At least the Hypex NCore 400 and 500 modules remain as good candidates.  

     So, please knock our socks off with that thing that you do with your analog power supplies!

Thanks for your participation,
              Tim 
georgehifi's avatar
georgehifi
10,312 posts
 
noble100658 posts04-13-2017 2:15amgeorgehifi,

Here’s a link to what I was referring to in my last post about reading of faster switching mosfets:

Yes I posted about these before, same guy invented the Mosfet.

https://forum.audiogon.com/posts/1414493

And yes it’s on the way, but this is just a small company able to supply Technics, not the world "yet"
Companies like Motorola will copy it and then the ball will be rolling, but with this transistor the Switching Noise Frequency has been doubled to 1.5mHz but I would like to see it to get to 3-5mHz.
This way the low order filter that has to be used on the output of all class-d amps can do it’s job well away from the audio band, without it’s effects (phase shift) or left over switching noise getting down into the audio band.

Cheers George
noble100's avatar
noble100
2,419 posts
 
Hi George,

    So, you're saying it may be a year or two before you buy your first class D amp?
     If you're going to wait until class D is absolutely perfect, the good news is that it'll probably be the last amp you'll ever need to buy.  
Good strategy.

Later,
 Tim
georgehifi's avatar
georgehifi
10,312 posts
 
So, you’re saying it may be a year or two before you buy your first class D amp?
If you’re going to wait until class D is absolutely perfect, the good news is that it’ll probably be the last amp you’ll ever need to buy.
Good strategy.
Yes, I’m waiting till it gets to what I believe will be time for me to turn to the dark side, with a 3-5mHz switching frequency, then it will address the problems I think it has "trying to filter out ALL of it" without effecting the audio bandwidth, and then my linear amps WILL become boat anchors.

One of the tell tale test will be to see in mags an almost square 10khz square wave without any buzz saw ringing across the top "without the use of test AP0025 (Audio Precision) inline filters" that are now being used by mags to hide it when measurements are being done, as I queried here on Stereophile.
http://www.stereophile.com/comment/565267#comment-565267
This then will show good audio bandwidth with total filtering out of the switching frequency.

This is what an unfiltered (by test equipment) square wave looks like on Class-D. If this was a linear s/s or tube amp a tech would say not to use it it has a major problem.
https://www.google.com.au/search?q=Class-D+square+wave&espv=2&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj_g9zOsaDTAhWMnZQKHax5C8kQ_AUIBigB&biw=1255&bih=782#imgrc=OFuO9FVLq5xJeM:

Cheers George
h2oaudio
38 posts
 
Tim,

"Hi Ho".  After I realized how goofy that sounded, I told him his  new American name would be "Henry" .  LOL! That is very funny. 

Speaking of which there are a pair of the Nord monoblocks NC500 for sale right now on Agon. Fund is very limited right now, otherwise I would pull the trigger on this just to find out how it sounds compare to the NC400 that I have. Thanks again for reading all of my rambling.

Henry
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