Discussion of Class D Amps Application & Experiences


With all the time off that our current situation has allowed recently, I became intrigued by the idea of class D amplification. I have always been against this type of amplifier but the more I have read the more I have also learned. There are lots of threads here on this subject many of which result in arguments about which amplifier class is better. I do not want to do that here. As I consider a class D amp I need to let you know that I currently use a fairly powerful class A/B SS amp and pre-amp into an efficient pair of speakers rated at 4 ohms. My choice of equipment has always been focused on musicality over absolute detail. I want the music to sound natural and not sterile. I seem to have achieved that sound. If I switched to class D amplification that would also be my intended goal although a bit more refined detail would be fine. I have considered pairing the amp with a tube pre to help achieve my desired sound. So why would I change? My goal would be to save money over my current gear while maintaining my desired sound.

I have researched brands such as Nord, Primare, AGD & Nuprime. I have also looked at brands such as Jeff Rowland & Merrill but those are way out of my price range. My target would be $6000 - $7000 or less. I'm about performance not price. So given that background information I would like to hear from those who have made the leap, what your experience has been (likes and dislikes), what amp did you replace and any comments about one brand over the other. Your experience with demos etc. Do you use a tube or SS line stage?
Thanks
falconquest
I would not switch just to switch unless there is something specific about Class D that appeals to you?

I’ve been running Bel Canto ref1000m Class D amps now for a number of years and still could not be happier. I did this because I wanted to throw the kitchen sink in terms of drive ability at my speakers which are known to benefit from that. I wanted something capable and good sounding that was also not too big, heavy and hard to deal with. Budget was limited but these fall into your price category at least the original retail price, though I acquired used for a discount in order to give it a try.

Still couldn’t be happier. If Class D did not work out I probably would have investigated building a smaller system around tubes but feel no need to explore those waters since. I’ve added other lesser Class D amps in other systems since. It’s the only way I go now. I do use a Audio Research sp16 tube pre-amp with my ref1000m Class D amps and think that is a very good way to go if one does not mind having to deal with maintaining a handful of tubes from time to time and the specific amp used has higher input impedance 60Kohm or higher for use with a tube pre-amp. No tubes in my 3 other setups built around Class D and those are all similarly good as well within their significantly lower drive limits (and cost).



I use Class D Audio CDA 254 amps in my HT side of things. With a nice tube line stage (Modwright SWL 9.0 Line Stage), with excellent results. They were kits, and the amp for my main channels has an upgraded power supply with two modules bridged to mono, @ 500 Wpc into 8 ohms.


My other two amps are SET 300B and SET 845. For very little money, you can have Class D to try out. Truth is, they sound great, even though they are relatively inexpensive.

Have fun with it. Easy to build, or you can buy fully assembled. Surprising how good they sound but, like most things in audio, you can pay a whole lot more, and get a little bit more.

Regards,
Dan 

I think Bel Canto is the place to look--great products in your price range.

There will be a bunch of other boutique manufacturers recommended, but BC for the long haul...

My other Class D amps  (in addition to afore-mentioned Bel Canto ref1000m monoblocks in my main setup)  are: 

  • Bel Canto c5i digital integrated amp in family room second system
  • Fosi Audio BT10 that does very well driving a pair of old Boston Acoustics A40 in a small 2-channel A/V system
  • 4 Class D amps built into Vanatoo Transparent One Encore powered speakers in my wife's sunroom
Years back I was at a NYC audio show and I gasped as I saw Jeff Joseph was running his Pulsars with BC Ref500Ms.  Given my prejudices at the time I was prepared to hear dry, brittle, lifeless sound but instead was treated to what I thought was one of the best sounds at the show, and my perception of Class D amps changed instantly.  I wouldn’t hesitate to try used Ref500Ms with something like a Linear Tube Audio ZOTL or Sachs SP14 preamp as I think that’d make for a glorious combination.  And if the amps don’t work out you can sell with little/no loss given BC is fairly liquid on the used market.  Definitely worth a try I’d say.  I’d make sure to have some good power conditioning for any Class D amps though.  Best of luck.