Who tried Class D only to return to S/S or Tube



And what were the reason you did a backflip back to S/S or tube.
As there are a few pro Class D threads being hammered at the moment, I thought I'd put this up, to get some perspective.

Cheers George
128x128georgehifi
I think it comes down to the simple reality that audiophiles are in general a very insecure group. Many like to think that whatever components they have are "the best" and will go to great lengths to put down the choices of others in a senseless and futile effort to somehow prove the superiority of their choices, blind to the fact that there are no absolute "right" choices in a quest that is entirely subjective, and thus personal.

Most high-end audio manufacturers cater to this insecurity in a market that thrives on "mine is bigger, better, more expensive (thus sounds better) than yours"...

Class d seems to be the red haired foster child for those with deep insecurities, or perhaps, vested interests, as it gets kicked around all the time. Perhaps because it offers a level of performance to the masses at a previously unavailable low cost, taking away much of the snob appeal many of the insecure so value...For those without vested interests or insecurities, it has proven to be an exciting and fulfilling option for amplification. Excellent measured performance, high performance to cost ratio, small, light, energy efficient, plug and play without any finickiness, the list goes on and on. Never mind the fact that many have dumped their tubes and high dollar boutique ss for class d...No wonder people feel threatened!

Clearly, the reason there are so many different types of speakers, amps, dacs, etc., successful in the marketplace is obviously because tastes and priorities differ. There are many roads to audio paradise, none more valid than the next; we shouldn’t be so concerned and critical with the route others take but as fellow travelers, wish them well in their journey.

My assessment is the technology continues to improve in regards to power supply and switching frequency so even better sound is possible but when done right it already is hard to fault so how much it will matter practically remains to be seen.   I will keep mine for a long time I think and when time to replace technology will only be even better. Much like computers and other forms of digital technology. 

Well said Mapman, I myself am not ready yet as I outlined, but once the new (let's call it 2nd generation)  far higher switching technology happens, I'm jumping in with both feet, compared to my setup at the moment the bass/upper bass of todays good class D amps is already better.

I just have to time it right when I'm ready to make the jump as my two biamped power amps can re-coupe enough $'s s/h before they become boat anchors to get a pair of good 2nd generation class D's, and the same to a degree will happen to the 1st generation class D's as everyone will want to dump them also.


Cheers George    

Hi George, what would you deem to be a sonically safe switching frequency for future class D modules?


Do you know of any such "Upcoming Attractions" with higher switching rates preparing their entry to market?


Meantime, Yesterday I checked the NCore NC1200 switching frequencies... It ranges from 440Khz to 520Khz., which is almost 5 octaves above theoretical human hearing range.


Honestly, I cannot perceive any artifacts or shortcomings from my amps... But there may be some audible artifacts that I am not aware of. 


On the other hand, I freely admit that I would be just as happy with a wonderful Solution monoblock, or a major AudioResearch tubed amp... I mean, apart from the heat dissipation, and reliability anxieties from ARC amps.


PS... My class D monos are not light... 160 Lbs per side. They are not furnaces by any means, but are relatively toasty to the touch during Austin summertimes.


Saluti, G.




The switching frequency guidocorona, may be 520khz, but it’s the amplitude as well of it not just the frequency and has to be filtered at the end with all that rms power by low order filters that have to take that power. 

From what I’ve been told by those in the know of Class D technology this has to be shifted up 5 to 10 times higher so the filtering of it on the output of a Class D amp can then also be shifted up higher, and therefore not be affecting the audio band, with audio band HF phase shifts or audio band HF roll-offs.

On most of todays Class D amps that try to get the highest frequency response they can get, you may hear a sizzle from a high bandwidth tweeter if you put your ear to it, if it’s not muted eg: in-between tracks on a cd.

Then there are those Class D’s that want to get rid of that sizzle which filter it even more savagely, then those ones can be starting to roll off the audio HF already at 5khz.

The sounds of the two can be then different in the upper-mids and highs, one being hard or harsh because it lets through some of the switching noise. The other sounding opaque or soft in the upper mids and highs.

Therefore to cure one or the other the switching frequency needs to be much higher so the filtering has little or no effect within the audio band.

Analogy: is to remember the early days of cdp’s with their brick wall filters, which on paper looked ok but sounded shocking, just because they wanted to show a flat 20hz-20khz frequency response. But in Class D amps this filtering is low order and happens at the end of the power amp at full rms wattage power levels, and the filters need to take all that power handling.

Then there's the SMP power supplies another problem again, that some Class D manufactures try to get around by powering with more expensive to make Linear power supplies.  


Cheers George