I went from Class D to Luxman A/AB - And most of what you think is wrong


Hi everyone,

As most of you know, I’m a fan of Class D. I have lived with ICEPower 250AS based amps for a couple of years. Before that I lived with a pair of Parasound A21s (for HT) and now I’m listening to a Luxman 507ux.


I have some thoughts after long term listening:
  • The tropes of Class D having particularly bad, noticeable Class D qualities are all wrong and have been for years.
  • No one has ever heard my Class D amps and gone: "Oh, wow, Class D, that’s why I hate it."
  • The Luxman is a better amp than my ICEPower modules, which are already pretty old.

I found the Class D a touch warm, powerful, noise free. Blindfolded I cannot tell them apart from the Parasound A21s which are completely linear, and run a touch warm due to high Class A operation, and VERY similar in power output.


The Luxman 507 beats them both, but no amp stands out as nasty sounding or lacking in the ability to be musical and involving.


What the Luxman 507 does better is in the midrange and ends of the spectrum. It is less dark, sweeter in the midrange, and sounds more powerful, almost "louder" in the sense of having more treble and bass. It IS a better amplifier than I had before. Imaging is about the same.


There was one significant operational difference, which others have confirmed. I don't know why this is true, but the Class D amps needed 2-4 days to warm up. The Luxman needs no time at all. I have no rational, engineering explanation for this. After leaving the ICEPower amps off for a weekend, they sounded pretty low fi. Took 2 days to come back. I can come home after work and turn the Luxman on and it sounds great from the first moment.


Please keep this in mind when evaluating.


Best,

E
erik_squires
Teo_Music

You wrote" your ear brain need to readjust to finding music in the noise.

I think you have it backwards! New class D amps like Purifi or the Benchmark AHB2 has sinad well below the threshold of audibility.

Now if a person prefers say a class A amp. That tells me their system needs some pleasing distortion (2nd order) to balance out the sound.
It's been a minute since my previous reply. Since then I have been enjoying an EVS 1200, Ric Schultz's highly tweaked take on IcePower dual 1200AS modules. And I loved it from the start as its 1200 wpc provides the authority my volumetrically large room needs to properly energize it.


Over those ~ 2 years, my cables have gone through a significant upgrade, and, I replaced my Emerald Physics (EP) KCIIs with EP 3.4s (12" concentric woofer with 1" polyester tweeters), but due to ignorance I never got around to replacing my optical cable with coax. Instead, thinking the dac in my Audio Alchemy DDP-1 + PS 5 needed upgrading. Not having the money to make a huge DAC/PRE investment, I tried a 1.0m Pangea Premier SE coax which was on sale from Audio Advisors.


I started a thread to discuss my journey, which included replacing the 1.0m with 1.5m then on to their 1.5m XL which is much more intimate, had much better bass (which is now way better) but slightly rolled off highs, until... Last night, after ~ 50 hours over a period of 5 days, the HFs opened up, and, bass/mids have really blossomed. Fantastic value for $150. How much better the more expensive coax cables are, I may never know.

The moral here is if one is not happy with what they're hearing from class D, it could be their cables

hth   
I consider the last pair of Class D amps I listened to for a long period of time the equal of Parasound A21’s in terms of warmth and color. Possibly the better in terms of noise.

The noise specs are better, but I never heard noise out of either of them. :)

There are a number of linear amps I would call more analytical than these, so in terms of broad class distinctions, I don’t think the idea that Class D is always analytical compared to linear holds.


I’m not asking you to love Class D uber alles, I just think you need to evaluate your choices on a case by case basis.


Of course, if your standard is a vintage Conrad Johnson amp, I can't help you. Everything will sound more analytical. :D


Best,

E
luka

I do not like dry amps of any kind. Early digital could be the actual cause of your statement, but it too has evolved. Most likely, your issue is with impedance mismatch between the preamp and the amp input buffer 

I have owned many amps; class A/B, one class A, and a handful of tube amps. None were perfect and most did not compare to my current class D experiences.

I had a similar experience to yours with early W4S amps, but none of the class D amps I’ve owned in the last 4+ years have been dry. That said, one does have to up their cable game with class D as it often exposes issues upstream

how many class D amps have you owned?

Over the last decade+, I have owned several class D amps; W4S (stereo and multi-channel), PS Audio GCC 250 (~ 10 yo, and still functions really well in my TV system), Emerald Physics 100.2SEs, Audio Alchemy DPA-1 which for almost 2 years has been my main amp in my stereo system, and PS Audio M700s.
Class D is to analytic. At the beginning, it sounds good, but after a while, you will miss something. It have no body, no personality.. you cann’t have “the” connection with the music. Our ears are analoque.
For me,still the best is Class A:pure, natural, real,more holographic.. you enjoy more. Class A/B is good for those who want more power ,those who wanna play loud...but sometimes you mis the attention  (the detail) and some tones suppressed by being too low. It does not represent a fair and real image. It is also reallly tiring for the ears, why many people have hearing problems in the long term .
OK, I've had the March Audio p252 in the system for two days (Hypex nc252mp), so I'll follow up with my thoughts in this contentious Class D thread.

I had a bit of a long strange trip comparing it to my old amp (Adcom 5802). When I first connected the March, I was sure I could hear a difference. A bit tighter in the bass, not as smooth in the highs. Was the image not as wide? The soloists seemed a little further back? A difference in Cymbal decay?

This evening I had a chance to A/B them, albeit under less than ideal conditions. Since I had to power them off before reconnecting, there was a bit of a lag between listens, and, of course, I'm getting up from the couch to do it. Just to complicate things, the March reverses the channels, so I had to be careful to connect right channel on my DAC to left channel on the March. I put in a pair of speaker cables with bananas instead of spades, to make it easier. After trying to volume equalize on the music, I started doing it on a 1k test tone (with a decibel meter). As it happens, the two amps have the same gain, so I realized I didn't have to change the volume at all. Eventually I got the switch down to less than 30 seconds.

The better I got at making the swap, the less I could hear a difference. When I started I was almost sure I could. Ninety minutes later I'm pretty sure I would fail a blind test between the two.

On the one hand, I am reasonably persuaded by the volume of tests that suggest well-designed and adequately powered amps will sound very similar. On the other hand, on very first blush I immediately started hearing some of the things detractors say about Class D. Hmm, which way do my biases run?

All in all, it was a weird experience.  But it's nice to have a cool amp here in the living room, so I can leave the A/C window unit off and hear the music. Also, with only the DAC/Streamer and the tiny p252, I could get rid of the audio rack and de-clutter....

Next I'm planning to test the Orchard Audio PecanPi DAC/streamer against my current rig (Cambridge Edge NQ).

@kijanki Thanks for your elucidation of some of what's involved with surface mount. I think a lot of people think that since we make tube gear by hand that somehow that means we don't have an education or something- or don't keep up with the times. We're using 603 components right now- as you point out, easy to do by hand. And probably too for production- depending entirely on volume of sales! On this basis, this statement:
it's impossible to create a "retail product" complete Class-D board, using all smd components, making it by hand soldering.
You say it can be done, but that would only be a 1 off prototype and not the production version.
-is simply false. Now at some point we may go to 402s just to reduce inductances and resulting ringing and radiation. But for now the 603s have worked out alright. If 'sales' translates to 100s of shipments, then its likely we will farm out the work.
it's impossible to create a "retail product" complete Class-D board, using all smd components, and making it by hand soldering
There appears to be a sleight of hand going on here, compare the above quote above to this one that appeared earlier:
To do that you need to buy either ready made boards then do simple mod and call them your own, if not and you want to do your own GaN Technology boards, you need the knowledge to design it from scratch, and you need some serious automated wave soldering machines to do all those smd parts that are involved, you can’t do it by hand. 
When comparing these two, we see that George had to back off from the idea that 'to do all those smd parts that are involved, you can’t do it by hand'; that's morphed into you just can't create a 'retail product' by hand soldering. Both statements are false. The soldering industry has all sorts of products designed for hand soldering work- and one of my employees worked doing production smd work all by hand.
Except for maybe a prototype, good luck hand soldering for retail production a Class-D that’s all SMD components like this cheap $34 Class-D stereo.
We're not planning to build a $34.00 amplifier and to be clear a $34.00 amp isn't going to have GaN FET output devices- such an amp would be all entirely on one chip. Its realistic to discount that comment as irrelevant.

Who said production boards will be soldered by hand?I didn't

I didn't, I inferred if you design a GaN board from scratch, you'd do the whole thing SMD because the GaN semiconductors are all SMD, therefore my statement was.
" They're not stupid and know it's impossible to create a "retail product" complete Class-D board, using all smd components, and making it by hand soldering"
@georgehifi  
Who said production boards will be soldered by hand?  Many small companies, including one I worked for, make small quantity of very sophisticated high density boards using Assembly Houses.  We used to make them with semi-automatic stencil printer, manual pick and place and 4 zone Heller reflow oven, but using Assembly house  ended up being much cheaper and better, quality wise.  Nobody sane would hand solder production quantities - too much time consuming equals too expensive.  We made batch of about 5 boards for prototyping and then about 100-200 boards in production quantity.  Using good Assembly House opens whole new world for designer (removes constrains).  Now he can design for higher density or even for BGA chips.  


Except for maybe a prototype, good luck hand soldering for retail production a Class-D that’s all SMD components like this cheap $34 Class-D stereo.
http://store3.sure-electronics.com/media/catalog/product/cache/1/image/600x600/9df78eab33525d08d6e5f...
@atmasphere  Ralph, perhaps I can help a little with SMT question (although you may already know all this) .  Suggestion to use wave soldering for your production is nonsense.  It was replaced by reflow soldering more than decade ago.  The only all SMD done with wave soldering today are low density high production quantity boards  (wave soldering is a little faster than reflow).  Even mixed boards are today soldered with reflow ovens + selective soldering (mini solder fountain).  Limitation of wave soldering is at about 20 mil pitch, but board has to be designed for that (orientation of components) and everything else has to be perfect.  It is perhaps good for 25mil pitch only (compromised adhesion of thin solder dam between pins causes shorts).  Also, board has to be designed for wave soldering in mind since recommended component land areas are different - wider (take more space).  I would design everything for reflow.  Hand soldering prototype with 50mil pitch components is easy.  I can do 25mil pitch large chips with 3D magnifier (Mantis) and micro soldering iron, but it is time consuming.  I've seen technicians who can solder 20mils.  For discrete components 0402 is the limit (already hard to rework).  0603 is practical and easy.  Best bet for small operation soldering would be manual stencil and small 4 zone reflow oven (bigger number of zones is mostly for production speed - faster conveyer belt).  Vapor Phase (drawer style) soldering might be also a good option (more accurate).  Better yet leave it to good Assembly House.  They make prototype quantities and small batches.  They often can buy parts at lower cost.  I went thru about 10 assembly houses before I found one that is wonderful.  Location doesn't really matter since you send them zip file and they ship back boards (leave everything to them!).   Novatronix in Chicago area is the best I know.  Sure, it will cost you more in prototype quantity, not to mention set-up charges, but debugging and testing poorly made board can cost you a lot of time (and frustration, and wrong decisions).  I went thru all this.
For your size of operation Altium software is most likely optimal.

Sorry, for all these details, but it goes toward possibility of making own design class D SMT boards vs using standard off the shelf modules.  The answer is - yes it can be done, many ways.

Have you tried reporting my post to moderation? 

No need to, because I see it has been removed, as admin must have read into your twisted response, and self shilling agenda.
  
They're not stupid and know it's impossible to create a "retail product" complete Class-D board, using all smd components, making it by hand soldering.
You say it can be done, but that would only be a 1 off prototype and not the production version.

I think you will find that the post stands because I've made no personal attack
Tweak didn't think so as he responded to your comment, which should also be removed, but then he's just your lackey .
@georgehifi If this comment is directed at me, could you explain how I was twisting your words? Are you saying that surface mount boards are only done on machines and can't be done by hand? How am I abusing you? Have you tried reporting my post to moderation? I think you will find that the post stands because I've made no personal attack, although I have debunked your statements which is allowable under forum rules.
You know exactly what I'm talking about and twisting it once again, still shilling for your self and abusing any opposition. Stay with tubes sunshine, you'll be better off.    
Post removed 
George, as I said in a previous post, you recently posted a list of manufactures poo pooing class D. I said it was because they see it as a threat to their non class D amps...... Which is exactly what you just said.
Just look at the calibre of those manufacturers v the ones trying to bring out backyard Class-D’s on these forums

You think RicEVS is ’stuck’ selling only modified IcePower class D? Why would you think he is not able to switch to GaN
To do that you need to buy either ready made boards then do simple mod and call them your own, if not and you want to do your own GaN Technology boards, you need the knowledge to design it from scratch, and you need some serious automated wave soldering machines to do all those smd parts that are involved, you can’t do it by hand.
http://www.onlysmt.com/Uploads/5b7bf3e74d93c.jpg
GFi
REALLY? You think RicEVS is 'stuck' selling only modified IcePower class D? Why would you think he is not able to switch to GaN anytime he feels it is ready for his Pixey Dust, and at a price his customers are able to afford?  I for one stretched to $2200

And again, ad nausea it seems, I and others here  have owned plenty of newer class D and are not bothered by the demons that keep you on your relentless soap box.
Why not just leave it alone. There has to be better things you could be doing with your time
George, as I said in a previous post, you recently posted a list of manufactures poo pooing class D. I said it was because they see it as a threat to their non class D amps...... Which is exactly what you just said.
The only interest you Ricevs and Mike Mivera have coincidently in degrading anything to do with Class-D GaN Technology, is because it poses a big threat to all your yet to be released non GaN class-D amps. Which you all so delicately push here on these threads, except for Mike who got what seems to be a permanent sabbatical away from Agon for pushing too hard.
Sorry, don't know what you're talking about. I can't recall nor can you point to a post of mine where I've 'degraded anything to do with Class-D GaN Technology' as you put it. FWIW we've been working with GaN FETs for quite some time. IMO it makes no sense not to.

There you go twisting things again.
  
The only interest you Ricevs and  Mike Mivera have coincidently in degrading anything to do with Class-D GaN Technology, is because it poses a big threat to all your yet to be released non GaN class-D amps. Which you all so delicately push here on these threads, except for Mike who got what seems to be a permanent sabbatical away from Agon for pushing too hard. 
Your
[sic]
twisting things to suite your self, I never ever said that you can hear these frequencies, I’ve always stated they have an effect and the "output filters used" in all Class-D amp to remove them have an audible effect, because they cause problems!!, and if the "output filters" are shifted up higher because the switching frequency is higher, then problems become minimized.
Hm. Your prior statements do not agree with the statement above. Here's an example- take a look:
GaN technology will finally get rid of these flaws of dead time and **switching noise**.
(emphasis added)
-what then, is 'switching noise', if not the residual??

In addition, as I pointed out before, most class D amplifiers use a 12dB slope in the filter. Now if you're up on your filter theory, you know that the phase shift artifact of a 12dB filter does not extend down to a 10th the cutoff frequency- that is a 6dB/octave filter that does that.

As for you getting abusive
I don't recall doing that and can't find any example of such in my prior posts. As you know, being abusive to another member violates forum rules. So I am quite careful in all my posts to avoid that! If you are referring to my prior post wherein this text occurs:
if you are saying you can hear 250KHz or 1.2MHz sine wave good luck trying convince anyone that you aren't a nutbag.
-that text is not abusive since I'm pretty sure that you are not in fact trying to convince anyone that you can hear to 250KHz or higher. If such is not the case, please let me know as that will be a bit of a surprise!

ricevs,
Also, very high power amps are large and heavy, with long circuit paths and lots of circuitry with plenty of opportunity for mismatch of transistors, etc.  As you say, remove what isn't necessary.  So the D'ag Relentless is probably not pure SOTA sound.  Why can't a $2200 amp with short signal paths and circuitry be SOTA?
ricevs,
Many interesting topics for discussion.  As you know, specs don't tell the full story of how an amp sounds in a system.  While I am not as technically knowledgeable as you or other manufacturers, I have learned that most of those specs are static measurements.  But music is all about dynamic transient responses, so static specs may be of little use.  Maybe square wave response is more relevant.  The rise and fall of the step requires an infinite bandwidth for perfect reproduction.  Slew rate, or any other transient impulse related measures?  Maybe designers know things which they keep proprietary, and confuse the public with these static specs.  The Merrills have distortion of as much as 0.08%, much worse than the D'ag Relentless, but I would bet the $15,000 price of the 114 that the 114 has better transient clarity than the Relentless.  Dan D'ag personally likes rounded full, bass heavy loud sound, whereas Merrill's goal is fast, clear, immediate sound in the 5th row of the concert hall.  In the end, the designer has a general sound preference which is expressed in all of his products, despite his specs which confuse the public.  The brass binding posts are a softer metal which contributes to warm, loose sound.  I used to listen to steel vs brass screws in the head shell of my tonearm.  I liked the tighter, clearer sound of steel.  So I would guess that the Relentless is still a softer sound than it could be with your tweaks.  Finally, when someone says that something is better, you have to know his values to decipher what that means.  If he likes warm, fuzzy tube sound, I know to go for the opposite of what he likes.
I emailed him good luck with that. Why he responded, I have no idea, but, he responded thusly " already have $800000 worth of OEM orders on the go. Along with $200000 of orders from my members. So not going too bad".
https://images-wixmp-ed30a86b8c4ca887773594c2.wixmp.com/f/84065033-987d-4a53-ac9f-172bca865101/dcmrb...
For what its worth, I've had SS integrated amps for most of my life. I finally made the plunge this year and upgraded my system. I listened to quite a few preamps and amps and ended up getting a Modwright tube preamp and a Bel Canto amp. Wow! What a difference in sound (to me at least). This is also my first tube piece. I know they're not 'burned in' yet but it's a sweet sounding system so far. If I ever go back to integrated amps, I'd like to hear the Luxmans. Thanks for posting.
Gfi
I believe that was Mike Mivera
Funny, I went to his site 2 days ago. Unless you are a prior owner of his kit you cannot get into his site. I emailed him good luck with that. Why he responded, I have no idea, but, he responded  thusly " already have $800000 worth of OEM orders on the go. Along with $200000 of orders from my members. So not going too bad".

Anybody buying it? Not me
George,
What amps have you removed the output filters from so you can test your "idea"?
Your kidding, your tweeters wouldn't last a nano second, if you didn't know??.

What we have here creeping up are manufacturers using the threads to promote their new Class-D products, it’s not on guys, there was one removed/banned totally from Audiogon not so long ago, take heed.

The latest Heisenberg is suppose to be way better than the old Max......same with the Relentless.  The new DAgostino has .003 percent distortion at full power, .03 ohm output impedance, 100K  bandwidth...all with no feedback!!!.....this is staggeringly better than any other Dag amp.  The old Dags measured just so so but some really liked their warm sound.  I have not heard either.....just what I gleam from reading reports from those that have heard.  My point is that you cannot expect SOTA at $2200.  I am sure there are better amps than mine.  How much more you would have to spend?  We shall see. 

Here is an interesting factoid.  The new Relentless amps have binding posts made out of massive brass.......yes, custom massive thangs made up of super lossy material.  Why would you make a "SOTA" contender amp and then put horrible brass connectors on the output.  They could of made them from copper, OFC copper, cryoed OFC copper, PCOCC copper, silver or ?  Remember, this is a quarter million dollars and they are mounting veiled hardware on the output.  I sent them an email about this but I am sure they will pay me no mind.  If they used the latest low mass Furutech or WBT copper or silver connectors they would have mucho better sound.  My binding post bypass system is even better.....but would not pass their "must look sexy" thang.  By the way, they are using $5 Neutrik xlr connectors on the input.  I use the much more expensive and better sounding  Furutech ones.....also better are the Cardas ones.  So, just imagine how much better the Relentless would sound with better input and output connectors.  Do these people really listen? 

Of course, when you get your Relentless amps installed you can bypass the hardware and hardwire.......he he.  However, this is how I listen....I hardwire two feet of custom balanced cable from my modded Oppo 205 to the custom input stage on the modded IceEdge module.  I solder my speaker wires directly to the module and directly to the xover in my speaker.  The first rule of tweaking is: remove everything not needed.

ricevs,
What amp have you heard side by side with your EVS 1200 that makes it "better" or SOTA, whatever that means?  I am not impressed by high  retail prices on hyped big brand names.  I heard an Audionet that was warmer and rolled off compared to the Mola Mola Kaluga.  D'agnostino amps are euphonic and rolled off, according to a few posters on various threads and a dealer I know.  The Audionet Heisenberg and D'ag Relentless may have high power, but there is no indication to make me think that for accuracy they are SOTA.
Ric hits the George issue on the head, eloquently. Not that his eloquence or reasoning will dissuade George from using cherry picked measurements to assert issues with Class D which are almost solved.


George,
What amps have you removed the output filters from so you can test your "idea"?  What amps have you raised the switching frequency on so you can again....test your "idea"?  You have interesting ideas.  That is all they are.  You have no proof.  More and more people everyday are listening to 500K switching amps using mosfets and they do not hear the "terrible mids and highs" you keep talking about.

On the other hand, I agree with you about switching at higher frequencies being a "possible" positive (apparently hard to do without drawbacks....Merrill even says so).  You could make the coil smaller and it would have less effect.  As far as dead time there are various ways of dealing with it.  Everything will be known about all this within 10 years.  In the mean time we have great sounding relatively modest costing mosfet based amps that are replacing class A and A/B amps all over the world.  Not that any class D amp (including the new Merrill GaN amps) is state of the art.  I am sure the $100,000 plus Class A amps are still the best there is (Audionet Heisenberg, DAgostino Relentless, etc.).

I really hope that GaN transistors can help class D get even better.  However, there is no proof yet.  Even the $36,000 Merrill GaN amps don't do depth or dynamics or classical music as well as the CH Precision stuff (according to one guy who had them both in his house).  Most of the class D amps out there are inexpensive, use off the shelf modules (including mine), are not being produced by serious tweakers, etc. and therefore are compromised.  I do 17 mods to the modules and hook them up in state of the art ways and sell wholesale direct.  This is why my amp is so good for the money.  It is not state of the art.....no way.  State of the art means the best available period.....Heck, that bar keeps changing every year....even at the $100K price range.  Class D is very good right now and will keep getting better and better at cheaper and cheaper prices.  If GaNs can help this trend then all is a WIN!  I have high hope for GaNs...let us see what happens.  Right now there are no (zip, zero, nada) tweaked out affordable GaN amps available (the inexpensive Technics is not a tweak product!!!).  This is going to take some time.  What is for sure (and I keep saying this over and over....so here goes again)......is that every amp with GaNs (when and if they get released) will sound different from every other amp with GaNs or whatever.  Every single thing you do changes the sound.  Unless you invest tons of time tweaking something you will never get what is possible.  I have been tweaking the IceEdge modules for a year now and am just now starting to ship.  Perfecting and tweaking takes time.  You will have GaN amps that do not sound as good as mosfet amps.....that I am sure of.  There is no silver bullet.  Everything has to be done right.  I hope that GaNs done right are another level better....I always want everything/everyone to improve.  I want everyone to feel happier and happier with each day.  May it be so.
That sine wave is at the switching frequency of the amplifier; if you are saying you can hear 250KHz or 1.2MHz sine wave good luck trying convince anyone that you aren’t a nutbag.
Your twisting things to suite your self, I never ever said that you can hear these frequencies, I’ve always stated they have an effect and the "output filters used" in all Class-D amp to remove them have an audible effect, because they cause problems!!, and if the "output filters" are shifted up higher because the switching frequency is higher, then problems become minimized. 

As for you getting abusive, I understand you are trying to promote and protect your upcoming new non GaN Class-D, because all linear amps tube and SS will go the way of the dinosaur once the new Class-D GaN technology takes hold.
Which it's artifacts are, even the non technical can see it in any Class-D's 1 or 10khz square wave from on the amps outputs, and in the phase shift the filter produces down to 4khz in many cases.
You can't see switching noise on any frequency a class D amp can amplify. All that can be seen is a sine wave known as the 'residual'. You've been told this before. That sine wave is at the switching frequency of the amplifier; if you are saying you can hear 250KHz or 1.2MHz sine wave good luck trying convince anyone that you aren't a nutbag.


Regarding phase shift, filters in most class amps are set to 60-80KHz and are usually 12dB per octave; phase shift thus derived is less that you would see with a 6dB slope (with a 6dB slope phase shift can be seen down to about 1/10th the cutoff frequency). So the 4KHz thing in the statement above is just plain false. You might see something at 20KHz though, but it would be slight even on an older class D amp.

I know your [sic] bringing out your own Class-D amps just like Ricevs is also using off the shelf boards (maybe slightly modded) that's maybe why the negatives toward the GaN Technology, that now even Texas Instruments are behind.
We have our own circuit and are not using anyone's boards. We filed for our patent over a year ago and expect the patent soon.

BTW 'switching noise' really isn't a thing unless the switching frequency is really low,
Which it's artifacts are, even the non technical can see it in any Class-D's 1 or 10khz square wave from on the amps outputs, and in the phase shift the filter produces down to 4khz in many cases.

I know your bringing out your own Class-D amps just like Ricevs is also using off the shelf boards (maybe slightly modded) that's maybe why the negatives toward the GaN Technology, that now even Texas Instruments are behind.
  https://e2e.ti.com/blogs_/b/powerhouse/archive/2018/06/26/the-sound-of-gan    
Uh, George, GaN amps still need deadtime. It *reduces* the need but does not eliminate it.
Deadtime is not a major source of distortion in a class D amp; you can double the amount used above the amount EPC recommends and not be able to hear it. OTOH the accuracy of the encoding scheme plays a much larger role in how much distortion is made.

The reason Technics is switching so fast is not because they don't need any deadtime. Its been done to reduce the residual waveform to a very low level and open up the bandwidth of the amp.

BTW 'switching noise' really isn't a thing unless the switching frequency is really low, in which case the amp won't be suitable for audio. IOW you're simply not able to hear it or any knock-on effects- plain and simple. 


Keep plugging away Eric, you live with a technology that has been flawed since it’s inception.
GaN technology will finally get rid of these flaws of dead time and switching noise.

No one here knew what GaN was till I posted up about it’s development at EPC years ago, before the Technics SE-R1 was released, I said then it was coming for Class-D and it would finally take Class-D up into the hiend for being for midfi and sub use.
  
I suggest all to wait till this comes about and enjoy your linear amps till then, otherwise you’ll buy into a Class-D technology that will be very hard to sell, once GaN has taken hold in Class-D in an affordable way.
Cheers George
At least I’ve given the manufacturers technical reasons behind it, you’ve given zip technical info on why the old technology is as good as GaN Technology.


You are the one who claims there are deficiencies which would be fixed. My point is and always has been:

  1. A measurement is not by itself audible
  2. I have encountered none of the audible claims you ascribe to Class D in general
  3. There’s no consensus on any of the technical items addressed in GaN amps being audible.


You are basing everything on literature, and very little on actual hearing and listening. Yes, I went from an old ICEpower module to Luxman, but hey, I would have gone from a Parasound A21 to a Luxman too. The idea that this proves all Class D are inferior or have a signature to all linear or GaN is just not in evidence. It's in your fandom.
It’s important to listen to different class D amps before commenting. As I have said before just because a design uses GaN it doesn’t make it automatically superior to other class D designs. Implementation is key, manufacturers can use the same class D module and the SQ will be quite different depending on how they are implemented. This will also determine the price of the product. From tests disclosed to us from a very reliable source, the current GaN amps are not currently THE best sounding class D amps, although still very good. They also tend to be much more expensive. Perhaps this might change in the future.
In reference to gfis incessant GaN, GaN or no class D rants, I suppose IF one drove a regularly aspirated high performance vehicle, then hopped on the same vehicle/engine but upgraded with twin turbos or a blower. The reat news is that eventually the tech trickles down.

HOWEVER, for many of us, the many benefits and sound quality of recent class D offerings has/have already put grins on out faces.. Case in point and speaking for myself only, my Audio Alchemy DPA-1 is immensely satisfying compared to my previous W4S and, Emerald Physics 100.2SEs, but my room demands more spls just to flesh out the music, not to blow out my eardrums

NOW, speaking to the current non-GaN offerings: if RICs pixy dust takes the IcePower to a much higher level for a mere $2200 (can’t believe Im saying "a mere $2200), but it is relative, then we can wait for GaN to come down to our budgetary level, Alas, who will buy or used D should they stumble across Gfis negative comments: GaN or bust? .

The only reason why I still have my DPA-1 is no one was willing to pay $850 for a product that MSRPed at $1995 3 short years ago, and got rave reviews in TAS and elsewhere. My PS Audio M700s @ 350wpa sold fast, but to my ears were no better, though double the power did a much better job of fleshing out my room, and likely do not compare to RICs EVS 1200 with pixy dust., but even the M700s were plugged into my 1800 CorePower, and since then, I have upgraded ICs, digital and speaker cables, so...
Not what I’m seeing.
How could you, https://media2.giphy.com/media/s4FDIU5rGfOpy/giphy.gif

That is opinion based on absolutely nothing.
At least I’ve given the manufacturers technical reasons behind it, you’ve given zip technical info on why the old technology is as good as GaN Technology.

And you have an invitation here https://forum.audiogon.com/discussions/what-amp-is-best-with-wilson-sasha-daw-speakers/post?postid=1...
Good for you, the majority in hiend don’t,


Not what I'm seeing.

that will change with GaN Technology and that’s fact.


That is opinion based on absolutely nothing.

I enjoy it immensely, actually
Good for you, the majority in hiend don’t, that will change with GaN Technology and that’s fact.
Interesting thread. Been reading about Class D and GaN amps for a bit now.Problem with posters here is you "feed" George and then blame him. Why do you care what he feels? Is he paying for what you are buying? He has the same issues with "active Vs passive preamps". But who cares? Why are you all so obsessed with him?Just move on and stay on the topic.
The problem is, George cannot exist unless we take his claims of sonic issues with existing, pre-GaN Class D seriously.

Issues which haven't bothered me in the least.

I guess George will wither away and vanish unless one of us, anyone else, can corroborate his claims of audible issues. Oh, wait,, he doesn't actually make claims the issues are audible, just measurable.

A conundrum.
You're distorting what I said, George. Old class D is still class D and you've been doing nothing but crapping on it this entire thread. Basically you're saying, if the class D that you're listening to is not GaN, then you're listening to crap. 
Well, I enjoy my "crap".
I enjoy it immensely, actually.