Class D Technology

Erik,

     I agree with you that, if I can't detect any issues in the audible range on my current class D amps due to their switching frequency being not high enough, than there is no need for concern and I should just enjoy them and my music.  Actually, this is what I've been doing since I installed the amps, I just tried to intently listen for any issues for a short period when I first heard of this theoretical issue.  

      Once an affordable class d amp with a switching frequency in the 3-5 mega hz range is on the market and there are any objective or even subjective reports that it sounds significantly better than current amps, I'll audition one.   I believe this is a more effective approach than not using class D until the theoretical  performance benefits of a 3-5 mega hz switching frequency becomes a reality, since the numerous benefits of class D amplification will not be utilized and enjoyed between now and then.      
      I would think just 2 of class D's benefits, sound quality and electricity cost savings, would be sufficiently convincing for many to switch right now.  If it's only going to get better, upgrade to class D now and then upgrade again whenever you determine future improvements are worth it.  The cost of world-class amplification has never been less expensive,as long as you're willing to be open minded, a bit more adventurous and let your ears guide you.


Enjoy,
 Tim  
 

Nobody can hear 500khz, it the filter that has to deal with it and what’s left over and the byproducts of it that is the problem.

What is left over is 500kHz. Byproducts are possible (modulation), assuming nonlinearity of motion, if tweeter can move membrane at 500kHz - no chance.

Filter or frequency have very little to do with quality of the sound, IMHO. It is related to quality of the modulator, slew rate of output devices (accuracy of the duty cycle), ringing caused by inductance and capacitance of output devices etc. Actually, increasing switching frequency can make it worse because it will reduce accuracy of the duty cycle - calling for deeper NFB. As I showed before (using 50kHz Lamm amp as an example) phase delay in audio band has nothing to do with extension and, if anything, might be beneficial since most of the speakers accelerate phase (much more) at these frequencies.

Also, increasing switching frequency will reduce amount of residue on the speaker cable but at the same time it will make it radiate much better.

H2O Audios' M250 Special Edition Mono Block Amplifiers

I saw a question on the forum about Class D amplifiers. Following the question was a comment about how class D amplifiers have distortions and lack of low level detail. I am not here to debate or disagree with anyone but just to tell of my experience with my H2O Audio M250 Special Edition mono block amps. My previous mono block amplifiers were Tube Research Labs  GT200s'. My pre-amp was and still is Tube Research Labs "The Dude". The sound was very desirable and I had that sound for a couple of years. During those years they were matched with JM Labs Nova Utopias and then Martin Logan Summit Xs'. The tube amps had the qualities that most tube lovers desire. They have rich harmonic textures, great 3D imaging and are very dynamic. They are triode amps with zero negative feedback rated at 200 watts. I must mention that I also have owned Sonic Frontiers Line Three SE amps, several Krell behemoths including the 650 mono blocks. I am a big electrostat  fan and now own the Sound Lab A3 PX speakers. Let me tell you Sound Labs are lightning quick and have tons of inner detail. But to really hear what they are capable of doing they really need an amp that just laughs at the load. Because these speakers are so revealing, any amp that has issues will be brutally exposed in seconds. That is where the H2O mono blocks come in. Boy you talk about power, grip, extension, lightning fast transients, inner detail, low level detail, it is out of this world! These amps just kick butt and have such grace and beauty. They took a long long time to break in but boy when they broke in! Never have I been so pleased with the music these things recreate. They have Ice modules in them minus the power section. The amps have huge analog toroidal power supplies. And massive caps for reserve power. I have a pretty good front end on this system. I have the Ayon transport, Ayon Skylla II DAC, Dude pr-amp. I have WireWorld power cables, interconnects, and speaker cables. My power conditioning is by Triopoint Audio it is called the Orion. Also I have the Tripoint Troy grounding system. The room is very carefully treated with sound treatments. I am just saying there is a great new world out there and most are blown away with what they hear from these amps. A friend of mine that has been in the recording industry for years said "never in his life has he heard solid state amps so free from harmonic distortions" as the H2O amps. In fact he said never has he heard ANY amp sound so beautiful period. I know I am biased but I must agree. Bottom line is do your home work about class D amps. Just like cars or anything else for that matter not all are created equal.

They have Ice modules in them minus the power section. The amps have huge analog toroidal power supplies. And massive caps for reserve power.

This is a huge step in the right direction getting rid of another point of noise (the smp), with the added lift of future higher switching frequency/filters and the benefits it brings, would spell the end of all linear amps. And Srajan's tubes below.

What Srajan Ebaen of 6 Moons said about the H2o M250's

In conclusion, I love these amps for different reasons than my tube amps.  The emotional connection is still stronger with the valves

 Cheers George 

This is a huge step in the right direction getting rid of another point of noise (the smp), with the added lift of future higher switching frequency/filters and the benefits it brings, would spell the end of all linear amps. And Srajan's tubes below.

Practically all supplies are switchers.  So called linear are very primitive -switching at 120Hz when voltage is the highest, creating a lot of high frequency noise.  Current is drawn in narrow spikes of high amplitude.  SMPS on the other hand, when done right, is far better in many respects.  It is quiet, switching at zero voltage/zero current.  It operates at high frequency that is easy to filter out (much easier than 120Hz ripple) and is line and load regulated (vs. unregulated linear supply).  It has fast response to load demands - vs. slower response caused by inductance of huge electrolytic caps. It tolerates DC on the mains (It even operates from DC).  Rowland switched completely to SMPS using them for class AB amps as well as for preamps (to lower the noise).  Benchmark improved S/N ratio by 10dB by replacing linear supply in their DAC with SMPS.  New class AB amp from Benchmark ABH2 also utilizes SMPS resulting in 132dB dynamic range.  

Why then, designers still use linear supplies with huge transformers and capacitors?  For two reasons:  First, it is very difficult to design good switcher.  Second, they follow market demand - many people believe that it has to be "linear" and heavy.