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
djones51:  I don't think that "insert" has to be literal!  There is a myriad of pins on those modules that likely allow for other configs.  Did you read any of the interviews provided or any others out there?  I don't have a dog in this hunt, I'm just asking if anyone has any experience in comparing Rogue's basic tube buffered input style to their TubeD designs.  As I've said, I live in an audio desert and shipping amps around gets kind of expensive quickly.

From Dagogo - MO: What is really exciting to me is that these amplifiers are much more than just a tube circuit in front of a class D circuit. We use only the modulator and mosfet output stage, and bypass all of the other circuitry on the amplifier modules we are using. We actually combine the tube and buffer stages with the output section, using proprietary circuitry that makes the output section perform like a tube stage rather than solid state. What is quite gratifying is that we have had numerous class D naysayers wind up purchasing them.

From Positive Feedback -  So I built what is a basic Hypex-type amplifier, as that was the baseline on one side; and then I guess our top-of-the-line Apollo mono-blocks were the design goal on the other side. I never started off to make a pure digital circuit; I just built one without the tubes in it—though I knew that wasn't what I ultimately wanted. But I wanted that as base line: like, okay, here's what the Hypex Modules sound like used as they were designed to be used, to build the same kind of digital amps that a half dozen other companies out there are building with the Hypex Modules, the big difference being that we only deploy the switching MOS-FETs on the output section of the modules and otherwise we bypass everything on the modules that Hypex supply that everyone else uses—we are not using the Hypex Modules' driver stages or their input stages.

Seems pretty evident to me that unless a respected and accomplished guy like M O'Brien is really being evasive, exaggerating or such, there is a decidedly different implementation of the tube portion and use of the Hypex modules, in those amps.

Lastly, I really don't care about the details and as it's been stated, likely correctly numerous times in this thread, it's all about the implementation details. This would seem to be a different implementation.  Just asking about experiences of any audible differences within the lineup, due to this implementation.


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.
I don't have access to the documentation for the Hypex modules used on these amps, but the connector is the same (except for one status line) as the Purifi module. There is no provision on the Purifi connector to bypass the driver circuitry. I suppose it could be possible to have jumpers on the card which would do this, but it seems unlikely since this circuitry (on the Hypex board) is an integral part of the feedback design that makes the Hypex module function. 

The Hypex and Purifi modules do expose the outer-most feedback loop, which is designed to provide a feedback connection from the speaker connections (or as close to the speaker connections as is practical). This is generally connected to the speaker output connections on the buffer board. It could be possible that Rogue is adding circuitry to this path to alter the Hypex module's transfer function, or someone integrating their front end buffer inside this feedback loop.