Class D Technology

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.

3 of the main reasons manufactures choose use smp (switchmode) power supplies.
Size/weight, efficiency, and cost to manufacture.
 
Well designed linear power supplies, are still the supply of choice for performance/noise and reliability. But they are costly and inefficient.

If/when I go to Class-D amps, I would also prefer to have a well designed linear power supply powering it.

Just quickly two that I can think of that use linear supplies for the best result they believe to power their Class-D amps are. Mark Levinson and Rogue Audio, there are many more from the upper end of town.

http://www.stereophile.com/content/mark-levinson-no53-reference-monoblock-power-amplifier#OXQH9C1XSJuv27p5.97

http://www.rogueaudio.com/PDFs/Pharoah.pdf   

Cheers George  

The main reason manufacturers of high end audio (like Rowland) use SMPS is low noise and line/load regulation.  You can find it in FAQs on his (or Benchmark) website. He uses SMPS  in preamps where size or efficiency play no role.

Yes, top manufacturers still use linear power supplies, but main reason is demand from people who, mistakenly, believe that if it has to be heavy to be good.