High end Class D amps?


Just an observation and a question. Are there 'high end' Class D amps out there that are just as good as Class A, A/B amps? I realize that's a sensitive question to some and I mean no disrespect---but whenever I see others' hifi systems on social media, all of the amps are A or A/B. There's always Pass, McIntosh, Moon, Luxman, Accuphase, etc. Where are the Class Ds? For folks out there that want more power for less efficient speakers and can't afford the uber expensive Class As, A/Bs, what is there to choose from that's close to those brands? Thanks
bluorion

Showing 17 responses by djones51

Well implemented class D amp should have no sound. There are companies that place tubes, resistors, op amps and other filtering to achieve a "sound" by adding distortion. The most neutral and best measuring class D will have a SINAD at least in the 90’s. Still one of the best measuring amps I’ve seen is the Benchmark AHB2 which is AB. Mainly try to avoid crazy tweaks they only make the amps worse.
I have a March Ncore P502. It's a very neutral amp which to me is the best thing you can say about an amp. Never heard an Apollon but they measure very well and inside they look tidy and well laid out. 
The best measuring class D amp modules at this time are the purifi and Ncore. That's not to say others like ICE or Pascal are not good, most likely they would be indistinguishable in properly designed implementation. As an example  the Dutch and Dutch  8c uses Pascal after testing various modules because they could get them for a better price and couldn't hear or measure any difference. I believe Buchardt uses Pascal as well. There is no reason class D amps should be expensive at least by audiophile standards unless the company uses high priced case design, name recognition,  added coloration through implementing purposeful distorion by way of tubes etc... , more features like the Nad M33, room correction,  dac, streamer. 
No never heard the Orchard but the owner posts on ASR if you would like to ask some questions. He had a 10% off sale before Christmas. 
Rogue isn’t putting tubes in the Hypex module. Go to their site and look at the inside of the Sphinx, those 2 small boards on the top are the hypex amps the huge board at the bottom with the tubes is theirs. Compare the hypex photos of the inside of the Sphinx to the stock photo at hypex they’re the same ucd 180’s
http://www.rogueaudio.com/Images/Sphinx3insidemed.jpg
https://www.hypex.nl/product/ucd180-oem/53

Here's the stock hypex module they use in the TubeD thing on a Dragon.
http://www.rogueaudio.com/Images/Draginsidemed.jpg
https://www.hypex.nl/product/nc500-oem/50
I'm no EE but the board's "wiring" or circuit path into the Sphynx's modules seems infinitely less complex than what's going on in the Dragon board's circuits going into the Dragon's modules.
If you look at the photos of the Dragon the hypex module plugs into the board the same as any other input buffer board. The tubes are not inserted into the hypex board and the input buffer board doesn't look anymore complex, that's not to say something in the buffer board could be different but the tubes in no way are inserted into the hypex, it's marketing speak for look we added distortion to a perfectly good amp. 

Operation is based on a non-hysteresis 5th order self-oscillating control loop taking feedback only at the speaker output.

Furthermore, the NC500 OEM is an unbuffered amplifier leaving the implementation of an input buffer up to the manufacturer. The NC500 is practically devoid of any sonic signature so this external buffer is a good way of tuning in a “house sound”.


It looks like in the Dragon they use the NC500. I assume they’re doing what every other manufacturer that uses this module they’re adding their sound with theirs or a third party external buffer. IMO it’s preferable to leave the signal as transparent as possible and not muck it up with distortion but to each his own.
I hope they are connecting the hot and cold feedback ,speakers,  clip indicator, overcurrent and power as well. 

We use only the modulator and mosfet output stage, and bypass all of the other circuitry on the amplifier modules"

I'm not saying anyone is being deceptive all I'm saying is the signal manipulation is occurring in the Rogue buffer board not the Hypex modules. There are no wires attached to the hypex in either the Sphinx or Dragan which is supposed to be TubeD or something.
If a linear amp was a perfect voltage source it would double every time the impedance halves. So if it does 500 watts at 2 ohms it will do 250 watts at 4 ohms and 125 watts at 8 ohms. It's not that it's important it puts out no more it's that even if we were talking about a perfect linear amp it couldn't . 
If efficiency is the definition of a perfect amp class D is closer than any other. 
^^ Really did you open one and look at it?

I looked at your photos none of those are in the Dutch and Dutch. 
If so then I tip my hat to Dutch and Dutch.

The 8c's cumulative spectral-decay plot (fig.6) is one of the cleanest I have measured, especially in the treble! In summing up the Dutch & Dutch 8c's measured performance, all I can say is "Wow!"—John Atkinson

NAD uses Purifi in the M33 and the C298. ATM also  uses the purifi in a couple of builds.