Class D Technology

Erik I’m just trying to frame up the comparison between the various amp technologies in purely technical terms as an extension of georgelofis argument against Class D based purely on switching frequency.

I am of the mindset that understanding the technology helps to make decisions where needed but alone does not dictate what sounds best in the end. Technology alone cannot predict what sounds best in specific cases. A system together makes the sound not just one component. Its a team sport as they say. Plus individual preferences vary for many reasons though some technical people have a greater tendency to associate these with specific aspects of technology that matter to them whereas others (I’d like to think myself included) are not so fast to jump to conclusions.

So I think we are on the same page in practice.

Guess what? My Class D amps were preceded by two different Class A amps that were fine on their own terms but far from perfect in my application. The Class A amps were preceeded by many a Class A/B amp and even a 70’s vintage Class G that was nice overall in its day especially if space is limited but sound quality could not hold a bone compared to any good quality newer amp I compared it to.

I heard the Benchmark amp at Capital Audiofest last summer (along with every other kind of amp imaginable) and thought it to be a top performer easily in the same league with the best I heard there.  I would own it in a heartbeat.   I am strongly considering giving Benchmark preamp/DAC units I heard there a try which if if successful (as I expect it would be)  would finally happily eliminate the last tubed  gear in my house.  I'm all about the sound.   The technology used is just a means to the end.

Here is another argument for Class D. It can be argued that once you get the bass right the rest is not so hard to sort out. I have found a lot of truth to that in recent years. Efficient Class D amps are both on paper and in practice hands down best at handling bass. That seems to be common knowledge based on application and sure enough I have found it to be true in practice. In a nutshell that’s mainly because of Class D high efficiency and the fact that doing extended bass well is exponentially more work for an amp than doing higher frequencies and efficient amps do it best. Just like efficient speakers make it easier for an amp to do bass well. The end result when done right (ie sufficient efficiency or efficiencies in play to facilitate doing the needed work) tends to sound similarly good in the end I find.

Guido,
Thank you for the detailed answer to my question yesterday. One attribute you stated,

Aliveness of "black" background... Also called the sound of the silence between the notes... Or the reproduction of ultra-low level information.

...reminds me a bit of what I found missing from the NC1200 Atsahs, at least compared to my other amps.  I am curious about what JRDG has done to bring out the best of the Ncore amplifier module but there are so many features incorporated in those amplifiers, over and beyond the stock Ncore modules, it would be impossible to isolate the specific contribution/benefit resulting from any one of the features.  I hope to hear a pair some day.

Can someone tell me what can be observed when measuring a class a/b amp that indicates its inferiority to pure class A?

In a class A amp as mentioned the output devices never turn off. Unless its a single-ended amp that makes little power, one advantage is that even ordered harmonics are canceled in the speaker load due to the opposing operation of the output devices. In a class A amp this happens at all power levels but not so with class AB.

Execution is a major portion of the differences between various amplifiers. For this reason it is possible to find inferior and superior amps in nearly all categories. I personally think D is going to win out over AB and A simply because of the cost. If done right, the output section is pretty benign and most of the sonic artifact seems to come from the input section and the converters.

Now this has nothing to do with tubes and both traditional solid state and class D still have inroads to make there. I think part of the advantage of D is that its likely that due to its simplicity and the input section being the lion's share of the artifact, that it will be able to eventually challenge tubes in a way that traditional solid state has failed to do (for those that doubt this last statement, if traditional solid state had really been able to challenge tubes, tubes would be a thing of the past. Gone. Nada. They aren't and that's really all anyone needs to know, and there are good sound technical reasons why this is so).

Because there is less to color a D amplifier, it should be easier to create the neutrality and smoothness that tubes have had all along. Not seen it yet, but they get closer every year.

Fact is the times have changed in audio. Digital is blossoming with tech that combines dac, amp, preamp, room correction etc.. all into one or two boxes keeping the signal all digital up until the point the signal is sent to the speaker.

Read all the recent reviews of my Lyngdorf 2170 or the Exogal Comet and Ion amp. The future is here right now. This gear is better than all those Class A /AB amps and separate boxes of tube preamp, dac with extra ICs and power cords. We are really experiencing a very exciting time in audio history. It is happening right now as we type these posts.

I sold my cutting edge and arduously fine tuned tube and SS gear nicely packaged in numerous separates and assorted hook-up wire for today’s exciting digital tech. The sound is better. I would have never believed it, but I experienced it and love the fact that is comes in one cooling running 15 pound package.

Some very special and unrivaled sounding digital gear is currently being introduced and it is nothing short of a sonic revolution. It will sweep our landscape and render our old sonic technology as mere collectors items of days gone by. This is not some sort of small evolutionary change from classic tube gear to modern day tube gear. Rather, this is disruptive change and innovation that will forever change our hobby. This is not somewhere off in the future folks, it is here right now. What a wonderful time to be an audiophile! Especially and essentially if you are an open minded Aphile not blindly holding onto past paradigms and experiences. The cheese has indeed moved. It may take longer for some to fully accept it😊

I still like soldering and building/modding point to point wired tube gear and enjoy the way they sound. However, I know my Lyngdorf is better in every way. While it is fun for me to drop in my latest tube amp project I  fully realize it is a hobby and not SOTA.