Class D = Trash?

georgehifi,

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

http://audiophilereview.com/cd-dac-digital/why-well-soon-be-living-in-a-class-d-world.html

      This transistor technology is called Gallium Nitride (GaN) and is poised to uproot the high-end audio world.  There's even mention of your favorite subject, higher PWM switching frequency, and how these new GaN FETS will enable it.

Tim

@pcrhkr - I had a crown xls 1500, which was the first gen if they're more tech. It was a great amp, especially considering it can be had new for not much more than $300. 

I recently bought a used pair of class d monoblocks by Ghent audio.. they are noticeably better than the crown. Just putting that out there.

Hi Tim,

Thank you very much for your understanding the tip on the Abletec power amp modules.  Unfortunately, I think all modules being offered by Abletec has built-in SMPS and there is not really a way to bypass/separate the SMPS from the amp section.  Even if that is possible, it would not be practical and/or economical.  This is the very reason I have gravitated toward icepower and Ncore so far, as these can be used with power supply of my own design.

I am aware of products being offered by Nord from England.  I believe, and I maybe wrong on this, that there is a misconception about the input buffer in most instances, in that it is choice rather than a necessity.  In reality, I believe it is a necessity first and foremost since most of these amp modules, may have a very low input impedance, in fact even lower than in the case of icepower 8 kohms in most modules, which is very low compared to the industry's standard.  One example would be in the Abletec's case, where if the module is being implement as is, its intrinsic input impedance is less than 2 kohms which is so tough drive properly for any preamp, except a very few preamps, and one being my Fire Preamp.

From what I have heard with the Ncore400, realizing that it is not the Ncore1200 which may sound completely different, Still, I believe that the Ncore technology is most appropriated to be mated with a tube preamp, and maybe preferably, a non-negative feedback design for best result, at least to my ears and in my system.  Thanks

Henry

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 

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