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

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

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.

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.

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.

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.

For the record: I've heard plenty of audiophile marketed, linear solid state amps which were pretty sensitive to speaker and cable impedance.

As my original thesis points out, we need to think about Class D amps like amps, with all their possible blemishes, instead of trying to assert an amp-class hierarchy which no longer fits current products.




Best,
E

This conversation turns a lot of my Audiogon impressions on their head. People who, I think, believe that great sound qualities can’t be measured are at the same time suggesting that because of inherent measurable design challenges of class D, that no class D amp can sound good. It also seems that more measurement-oriented folks may be coming out against class D because...I don’t know.

Let me be clear, I like measurements. But a measurement is not inherently audible or valuable. An oscilloscope does not work 40 hours a week, and go home to listen to music. There's a big difference between a measurement and pleasure or desirability.


If there is 100kHz noise on an output, I'm not convinced it is audiuble unless I can hear it. If you go from 0.01 to 0.00001 distortion I'm not willing to pay 1000x as much for the latter.


People who cherry pick a measurement to make broad claims about the inferiority of one technology over another are not objective. They are just biased.

I don't have a problem with GaN amplifiers.

I have a problem with claims that they will fix problems with Class D I haven't heard in 30 years from someone who has heard neither.

I won't be responsible for George's lack of self control. If I can't say "I like Class D" without him abandoning his family, friends and life to respond with hundreds of pages of random facts about Class D it is not my fault.

This is what I mean about George doing very little listening, and therefore making it hard for his arguments to be persuasive.

Most others on this thread, starting from myself, are commenting from actual listening experience.

Notice please in all my threads how often I’ve gone after listeners who post their personal experience. Never. I may not agree with them, but their experience is their own. When it comes to Class D in modern times, George rarely goes there.


Now, purely from theory, the Technics qualifies as an actual digital amp with DSP used to compensate for speaker impedance interactions. You can't separate the type of transistor, switching speed, and DSP to tell which is responsible for what.  I do think the DSP impedance compensation is very cool, but it means a second DAC in your stream.

Hearing has never had anything to do with George's dislike of Class D.

It's more of a passion to dislike them. A reason to go on.

Oh, I don't mean to shut George down. That would be impossible.


I just want it to be clear that despite the mountains of posts he's failed to persuade.

George:
I clearly meant you are outnumbered here in the forums, with most people responding at least not trying to hijack a thread with a strawman army. You are also vastly out gunned, with responders bringing in personal specific listening experiences which are far more valuable than your uncorrelated theories of why current Class D must sound bad.

Also, in terms of music listeners, I'd bet right now the ratio is 70% listening via some class D, probably voice controlled appliance.

A few years ago I did a local sale on a Conrad Johnson tube preamp which was connected to a Class D amp. When the buyer came over for a listen his first question was, what kind of amp is that? He then went on to point out how impressive the two sounded together and yes he did purchased the preamp.

This is one of my classic combinations!! CJ pre with solid state amp. I haven't tried Class D with ESLs, but in the past I loved that combo.

Good luck with that one Eric.

Thanks George. I've had very good luck given the positive responses on this thread and my previous ones.

You are vastly outnumbered, and when cornered admit you won't actually listen to Class D.  Hah.

Best,

E

Not sure if you are intimating that it is the ICE tech that is an issue (to you) or if the SMPS is not a problem to you.

I have not, and will not, use the term SMPS to refer to a power amplifier in general, since the last two initials stand for "Power Supply." To use SMPS to refer to a switching audio amplifier in total is incorrect. It negates several components entirely, and fails to acknowledge the improvements that have been made to make it wide band.


ICEpower refers to a particular brand of Class D which is owned by B&O. ICEpower 250 ASP is a specific model of amp which includes a power supply in it, and it is what I have the most amount of experience with.


To repeat my original message: The tropes about the terrible sound quality of Class D amplifiers are not supported by any of the many reasonably good Class D amplifiers out there. Nor is there any evidence that you can hear the switching noise anymore. Not for decades.


If we want to talk about the positives, and negatives, we have to stick to experience and specific models. All amplifiers have a negative. All have something they could do better or differently. Seeing 1 measurement and going "look look, Class D is terrible" is not scientific. To close the loop, you have to connect it with listening. And that’s where a lot of anti-Class D bias looses all of its wind.

Again, referring back to my original post. I like this specific model of Class D better than some linear amplifiers, but not better than the Luxman I'm listening to now.

With this specific example, and I don't think it was by any means the best available today, I never heard anything that said "Class D."  So I imagine that not only are there a lot of other Class D amps that don't sound bad, but that they've made significant strides.

Best,

E

The words of a man who has personal experience in a subject is called expertise.

The words of a man who quotes others is called opinion.

You say you can’t hear it that’s fine then live with it, but stop starting new Class-D threads to look for confirmation/cred from everyone about how good it is compared to the best linear amps.

Says the man who has to, absolutely HAS to jump into every thread that includes mention of Class D.


Unlike you George, I can use specific examples and talk about exactly what I do and do not hear. Others who have or are enjoying Class D can also cite specific examples of what they bought or what they listened to.


Some may not like the Class D amps they have heard. That’s fine. The whole point of this article was that I was happy with a specific type of Class D but went to Luxman anyway and that the collection of Achilles’s heels you carry around with you, like a homeless man and his shopping cart, have not made it into my listenable space in a very long time.

Don’t need to, they are all variations on a technology that has an achilles heel that can’t be fixed.

But only George can hear it.

you started the personal slurs again

You meant to type "provided  historical context."

Erik instead of burying your head in the sand about the problems that Class-D has had since it’s inception, with switching frequencies+filters,

The man who simply refuses to listen to any view but his own would like to claim I buried my head in the sand.

No, George, my original post was all about a progressive view point towards Class D amplifiers. Your view is from the 1980s and has moved nowhere. As we’ve discussed with embarrassing regularity, your claims of the superiority of Class A/B amplifiers over Class D based on measurements alone has no justification in terms of audibility of any amplifier made in the 21st century.

My claims are from personal experience, along with those of other audiophiles who have visited. You can complain about the sound quality of specific amps, but the trope is decrepit.  I am however astonished at your powers of necromancy in bringing them up over and over again despite so many positive reviews from Audiogoners to the contrary.

I’m making blanket statements about all of class D for a reason.

To punctuate my original post: Bunk.

When I started this thread I was really worried that Goerge would have gotten too old and tired not to raise the same tired and irrelevant tropes he always does, but whatever held him back before, it's good to see he's recovered and fit as a fiddle, cutting and pasting the same things from the dozens of other threads on the subject.

Thanks @melvinjames, Honestly I think it's just 30 year old biases. We might as well be complaining that solid state gear isn't as reliable as tubes again.

Best,
E

Not if you talk to a designer of a class D amp :)

Your need to go on ad nauseum without actually addressing the points I made is actually kind of like watching a fetish in public.

But even with an digital source built into the amp, its still an analog process.

There are people who are going to argue all audio amplifiers are by definition, analog, but we don’t call DAC’s analog either.

If an amp samples the input into discrete voltages, at regular intervals (i.e. has a sampling rate) and has an output controlled by those inputs, even if the last stage has an analog feedback loop, then it is 95% digital, and the last part had an analog feedback loop I call bunk on those who want to insist that makes the whole amp analog.  Calling it a digital amplifier is a lot closer to the truth than calling an analog amp.


Best,
E

They are an entirely analog process.

 
And for the most part in the nCore/ICEpower/Pascal/TI world this is true, though recent amplifiers from Technics blur the line further, with an A/D stage, DSP processing and unknown amounts of analog feedback at the outputs.

My main point about Class D power warm up really is just to avoid making buying decisions based on a cold demo as you may get an unfair experience.

I'm not suggesting you listen to the D's for two days. That's not part of my recommendation.

Best,
E

FYI, the retail price of the 507ux and ux ii in the US were identical until the latter was introduced.

The only difference in the two is a refinement in the feedback loop.
Luxman makes a lot of different models, so it is easy to confuse one for another, especially going by pics alone. :)

Best,
E

TBC: Yes, the ear brain mechanism is very pliable, and constantly adjusting.

No, this theory is not a good fit for the multiple case studies reported.

Your theory explains 1/10th of the evidence.


Equivalent of explaining that Columbus invented sailing.

Please, people, the ear and brain combination are a mutable shiftable changeable trainable device. Like the rest of your body, brain and eyes, etc.

While this is true, in general, it does not explain what I have heard. First, the time I went away from the system and turned it off for two days. I didn’t really listen to music while away.


Second, going from a warmed up Class D to the Luxmans did not show the same audible issues as I did when listening to cold Class D.  As others have noted, you don't have to listen to the amps for 2 days to have their sound change, just leave them on.


When the Class D’s were cold they sounded cold and harsh. When I went from warm Class D to Luxman, I did not hear Luxman being warmer, or less harsh. I heard the Luxman being less warm, with more extension.


Please try again.


Best,
E

Stibi,
I think that those amps may have done the same to a lot of linear amps too though. :)



Best,

E

Let me clarify myself, a little.

While I like Class D, and in some cases a lot more than certain Class A amps, I do think the ability for them to emit noise back into the power line or radiate it to nearby devices is not zero. So I advocate the uses of shielded power cables and using multiple filter banks to isolate them from other gear.


A detailed coverage of my thoughts on the matter are here:


https://inatinear.blogspot.com/2019/04/power-management-for-frugal-audiophiles.html


Best,
E

audiofun:
I used the self-powered version of the ICEPower modules, and I simply have not experienced the differences you did.

I did keep the amps far away from other gear though, and used ferrites on the power lines.

Best,

E

It’s not the class D (ICE in this case) that’s the issue. It’s the sucky SMPS’s that are the problem.

Well, that certainly was not my experience.

@willgolf

My previous Class D’s drew about 7 watts while on, and they sounded a lot worse if they weren’t on 24/7, so yes.
Best,
E

I'd like to offer a correction.  I said:

I didn't say I did a test blindfolded. I said if I were blindfolded I could not tell the difference 

But actually, I kind of DID say that. Sorry.

What I meant to say was:

"I knew which amp was which, and even then I could not tell them apart."

Apologies for forgetting what I just wrote.

Best,
Erik

@firstnot

What we talk about are personal experiences, which scientifically we'd call case studies. If you buy solely on scientific studies and discount case studies, including your own experience, you are definitely in the wrong hobby. That's like buying wine based on Ph factor alone.


I didn't say I did a test blindfolded. I said if I were blindfolded I could not tell the difference, meaning, with my eyes wide open, I was unable to perceive a difference between the specific ICEPower modules and a well known linear amplifier, even knowing they were different.


The quality of sound from gear made by Sanders / Coda is not the point of this thread, but I have strong opinions on the matter and would be happy to debate you elsewhere.

To repeat, the point of this thread is not "my amp sounds better than yours." It is that we need to stop using 1990's Class D sound to describe modern Class D. Treat modern Class D amps as you would any other amp and decide what to buy or not based on your own ears.


Best,

E

Hey @mapman

I bought raw ICEPower modules and put them in cases as specified. Speakers were customs with data available here:
https://speakermakersjourney.blogspot.com/2017/12/snr-1-two-way-high-end-diy-monitor.html
Yes, indeed, amps sound different. My point was not that Class D was always worse than Luxman, or Luxman better than Benchmark.

My point to the entire post was that we have to move beyond talking about Class D as being inferior and treat them like we would any other amp.

Erik

Hey @laserjock1963
I've seen the reviews but never actually seen one in person.
Best,
E