Comments please on: NAD M23 vs c298 vs. other newer Class D

If Class-D amps can be carefully laid out in a stereo two channel format with "plenty of power", relatively low distortion, with careful isolation of components for each channel, in a shared chassis - what would be the Top3 reasons some manufacturers still choose to make Class-D amps as mono amps?

@decooney @hilde45 The main reason is to reduce colorations.

Mono amps insure there is less noise in their power supplies and allow you to place the amp right by the speaker, thus keeping the speaker cable as short as possible. The reason that is important is no speaker cable is really correct; they all have mismatches with the speaker. Your best bet to minimize those errors is to keep the speaker cable as short as possible.

That is also the reason we use a balanced input. If your preamp supports the balanced standards then the interconnect cable's artifact (the reason interconnect cables can be really expensive) is minimized or non-existent. As an example I run 35 feet of interconnect cable at home and often at audio shows too. 

So that allows for the least coloration; something that is a lot harder if a stereo amp is used. 

Thank you, Ralph!

My WT amp ultra (upgraded Wiim amp) is only $1300. It sounds clean and musical. Compare their sounds below. Alex/Wavetouch audio

The sound of  NAD C298

The sound WT amp ultra

WT amp ultra

"@atmasphere So that allows for the least coloration; something that is a lot harder if a stereo amp is used."

Thanks Ralph for your explanation.  On a related topic, something I’ve come across in many reviews about different Class-D amps [over the past two years] has to do with a particular explanation describing how the sound can be somewhat "blurred" or "co-mingled / blended" together more so between the left and right channels. As I recall, most were Class-D stereo amps vs individual mono amps for each channel. 

For my own reference, some of my lower quality Class AB solid state stereo amps do this, yet my pure Class A solid state amps is a bit better at channel separation, not as blurred together. However, my monoblock tube amps keep it all well separated, and distinct between the instruments in a very distinctive way. 

Admittedly, I’ve not tried any known high quality Class D mono amplifiers yet. I may try this some day when it becomes a compelling "no brainer" to do it. 

ASK:

We get it that you are an engineer. Here is the curve ball question about the "sound". When you compare your own Atma-Sphere TUBE amplifiers to your new Class-D mono amplifiers, what can you share about the sound - What is similar and what is different about the sound stage, depth, placement of the singers voice (more forward or back), and what about channel separation and instrument separation. 

What is similar, what is different, comparing the sound between your Tube vs. Class D amps?

Started doing some extended comparisons between:

(a) Hypex based amp (DIY from friend who’s a master builder)
(b) Purifi-Eigentakt 1 amp (NAD M23)

Generally the NAD was better:

• more “rounded” or easier on the ears for louder passages (e.g. vocals, piano, sax) that the Hypex felt “cringey”
• more body, presence, texture in instruments -- more “reality” to them compared to Hypex
• good soundstage, width and depth (but not better in this regard)
• fast and dynamic (but not better in this regard)

That’s the report so far.

Overall: NAD winning by more than a little bit.

My curiousity about @atmasphere Class D amps is growing. Watching reviews and interviews with him about the amps. At the moment, I have a strong suspicion that what I like in tube amps is going to be more present in his Class D’s than in the M23.

For now, though, the trials -- NAD M23 vs. Hypex and then the winner of that competition against the Pass XA-25 will go on.

The key question will be: what do the better Class D amps bring to the table that the Pass cannot with my very efficient speakers?

I am NOT getting rid of the Pass. I am looking to see whether there is something in a Class D that add a new and different character to my stable of amps.