Deciding if I like Class D.


I recently purchased Goldenear 1R towers. I was powering them with my Oultlaw 770 initially. I’ve also used a 350 wpc McIntosh a friend owns.. I realize the Outlaw is not audiophile grade, but it’s actually better than most give credit for.  Anyway...

Even though the built in subs are powered, the towers still benifet from a good amount of power, up to 650 rated, so I have been on a quest to find the right amp.

I purchased a set of Hypex Ncore NC1200 Monoblocks with custom buffer boards, and it came with Sparkos 2590s Opamps as per my request. The Goldenears are slightly forward, and I was told Sparkos was the way to go because the were warmer in presentation .

So, I let the amp break in, playing it when I wasn’t home at 85 to 95 DBs for a few days, and gave it some good material to assess it.

I was immediately disenchanted, because the amps sounded very dull, and the highs were rolled off considerably. When compared to the A/B amp the D was not pleasing to my ears. My hearing is slightly diminished from combat, but the A/B was much more detailed.

So I called the company that made amp, and he was very polite and helpful. He sent out a set of Weiss OP2 and Sonic Imagery 990 opamps,to see if I preferred the sound characteristics. Well, the difference was significant.

I am using a Marantz 8805 preamp in pure direct mode . Using BlueOs Streamer, using both optical, and a analog outputs for the testing.. Analog is required to get the MQA files to give full resolution.

To me, the Sparkos just killed the sound. I could honestly see why reviewers would say the treble in particular, was not musical. If I had to live with that sound, I would not..

The Sonic 990 was much better. Much more detailed, better sound stage, just better overall.. Then, I tried the Weiss. Well, that was another level altogether. It sounded like the McIntosh, perhaps better in some regards, but to be honest, it takes a lot time and A-B testing to really be sure. None the less, after hearing the Weiss, it was obvious that they were superior to everything else.

So, I called the manufacturer to let him know my findings, and he said, well, I should give the Sonic 990 another try. I asked why. He said the Weiss would add over 600 dollars for the two pair over the Sparkos and Sonic Imagery.

So, that would bring this setup to over 3100 for the pair. And I could buy a ’good’ high power A/B for that used or even new.

I’ve read a lot of opinions on this forum, and I know the consensus is that D is good, but not great. I know people usually defend what they own, so I needed to hear it for myself. Without a basis of comparison, I’d probably never know the difference, but to be honest, aside from the Hypex getting much louder, and without any audible distortion, I really think the A/B *may* still be more musical, but dammit, I’m not 100% sure. It’s subtle at best.

After hearing the Weiss Opamps, I’d not be satisfied with anything else, but with them, the price is commensurate to A/B.

I’d really appreciate your input on this subject..

BTW, I have purposely left out the company I bought it from, because I think component wise, they are all pretty similar,and I don’t want to start any BS.

I will say though, at the end of the day, the op amps make-or-break the amplifier.

Thank you
Rick




knowitall
"...Then, I tried the Weiss. Well, that was another level altogether..."

A few hundred dollars is not much when you get a lifetime of musical enjoyment out of good gear. My suggested upgrade path for you would to upgrade your pre-amp and keep the Op amp you liked. 
"...The Marantz 8805 is quite good. I don't think that's a factor here..."

Have you ever tried a high end preamp in your system? 
Post removed 

knowitall OP
I purchased a set of Hypex Ncore NC1200 Monoblocks with custom buffer boards, and it came with Sparkos 2590s Opamps as per my request.
I was immediately disenchanted, because the amps sounded very dull, and the highs were rolled off considerably. When compared to the A/B amp, the D was not pleasing to my ears. My hearing is slightly diminished from combat, but the A/B was much more detailed.


This is probably the reason for what you heard (red trace) with Class-D a massive phase shift starting at 1khz and getting to 70 degrees!! out of phase by 10khz!!! with rapidly increasing distortion (blue trace).
https://ibb.co/3Sg9bZY

All this is put down to the low order output filter, that has to filter out the 600khz switching frequency from the output.

Simple, if the switching frequency was made far higher from 600khz to 1.5mhz as in the (GaN Technics SE-R1), then the output filter can be moved up accordingly 3 x higher along with the "phase shift" and "distortions" and as a result most of those two nasties will then be well out out of the audio band.

Cheers George