Class D: Turns Out it Does Suck!

[firedog]

First, another silly attempt of yours to troll, isn't it?

I will partially take the bait:

 

1. This is mostly comments of guys who don't do Class D. Not exactly an objective group. In addition, designing Class D properly takes specialized knowledge and experience if you want good results. Probably lots of these guys, even thought they may be great designers, haven't given the time or thought to Class D to make it work, and don't truly understand it on the most sophisticated level.

 

2.  This is only a few years old, but already dated. Several newer generations of various Class D technology have come out in the past few years. General consensus is that they ARE competitive with non-Class D solutions, and often thought to outperform them, dollar for dollar, except at the most expensive, over $10k levels. 

[firedog]

46 minutes ago, GUTB said:

 

I'm sorry if quoting legends in amp design is "trolling", but I don't believe there have been any fundamental improvements in class D since then....has there? Which specific modules are you talking about?

Trolling is when you give your " innocent"quotes a title like "turns out class D does suck" - that's about as blatant a troll as you can get.

 

Specific modules? Less important than how they are implemented. But to name just a few, some of the newest implementations of ICE, Ncore, and Nuprime. All out since that article and all reviewed - by both hobbyists and professionals -  as being as good or better than anything in conventional amps at their price and often far above their price.

When someone says a $2000-$5000 ClassD amp compares favorably to a well known "audiophile" amp costing that much or even twice that, I think they are saying it is a damn good amp, I.e., it doesn't suck.

 

Your list of experts is no more authoritative than the many amateurs and professionals who don't think class D sucks.

[firedog]

1 hour ago, GUTB said:

 

I've heard a couple of class A and A/B amps which suck. But the problem with class D is that it sucks by nature. That's not a troll, but a hard fact. Vladimir Shushurin from Lamm was the most brutal about the issue, calling class D feeble with a bunch of diseases on top of it, while we deal with all of its shortcomings with modern medicine.

 

Guess which one of these 10 KHz square waves is from a class D and and which one is from a class A amp:

 

 

 

And it proves absolutely nothing about Class D amps as a class. Your so called "fact" is an opinion, not a fact. 

 

We get it, you don't like ClassD. 

 

What you don't get is that nothing you think is provable. Every argument you are going to make can be countered - believe me, we've already heard them all. The arguments aren't new. 

Like the rest of us, you are free to think what you want and come to whatever conclusions you want. 

What I don't get is your compulsion to try and prove it and argue about it.

I think that defines "troll"....

I'm out of this one, I can tell it will be a useless so-called "discussion".

[firedog]

5 hours ago, Ralf11 said:

I wonder why Audio Research dropped class D ??

Relevance?

Do you also wonder why other brands have picked up Class D? 

 

Neither is actually relevant.

Companies make decisions like that all the time. Lot of different reasons. Sometimes they drop a technology and then readopt it afterwards.

 

Sometimes different companies disagree, imagine that. None of it proves anything. Expert amp designers also disagree. I've yet to understand how cherry picking the expert who goes along with your opinion proves anything - it's not as if all respected amp designers agree about class D. 

Same thing with all other types of audio components. 

[firedog]

1 hour ago, The Computer Audiophile said:

I've spent a lot of time listening to class A, class A/B, and class D. In my experience class D amps have the biggest range between implementations. Meaning, some of them are really good while others are horrible. The class A amps I've had and heard, are all really good. But, almost nobody build class A anymore so the sample size is rather small. Plus, who is going to go to the expense of building a bad class A amp. 

 

One issue with class D is the marketing. Manufacturers have been saying for a long time that class D has finally caught up with A/B or finally overtaken A/B etc... In many cases this hasn't been true. These statements have only hurt the class D technology rather than help it. For example, I had a manufacture over to my place within the last year, who claimed its class D amp could compete with or better the best class A/B. I said, fine, let's put it to the test. After listening to my Constellation Audio Inspiration Mono amps he said wow that's awesome, now let's put my gear into the system. After a few seconds his tail was between his legs. He was surprised at how much better the Constellation amps were than his. I think he was caught up in his own marketing and couldn't envision the outcome of the test beforehand. I knew what the outcome would be because I had already done it before he arrived. 

 

My bottom line is that I'm more skeptical about class D than any of the other technologies. This is mainly because of all the promises we've heard over the years and all the less than stellar results we've heard to back up those promises. 

I don't know what class D you heard, but I'm assuming it cost less than your $20K pair of monos. So basically, if he had been more modest with his claims, something like "my Class D is as good or better than any Class A/B amp near its' price", you would have been fine with both the amp and the claims.

 

I don't claim there's a Class D amp as good as the best of A/B amps, like your Constellation. 

I do claim there are some NCore, Nuprime, PS Audio, and ICE implementations which are as good or better than anything close to them in price, and they also give you  more power.

I heard the active Kii Three system, powered by a proprietary version of NCore (made specifically for these speakers/drivers). That amplification wouldn't be beat by conventional amps I know of that cost even several thousand each. And there are 6 of them in each speaker.

I've heard some of the  other recent stand alone Class D amps I mentioned above, and they would also fall in that category, 

[firedog]

9 hours ago, GUTB said:

 

As usual, no actual counter-argument, just class warfare.

 

The measurement is from the NAD M22. But please, find a single class D amp that Stereophile measures that looks much different. They used to show measurements with the low-pass filter off, which produces waveforms like this:

 

 

Anthem Statement M1.

 

Amplifier bandwidth is beneficial to the audio band.

 

Hilarious that you bring up the M1 as a counter. Do you bother to read the reviews in stereophile also? Here's what the reviewer, Kal Robinson had to say in his conclusion
 

Quote

But in its present state I cannot recommend the M1. It imposed a tonal signature on the sound that was simply not neutral. Many successful audio products fail to meet this criterion, and some are perhaps designed to do so, but I don't believe that this was Anthem's goal. Perhaps, as they've done with the upper treble, Anthem will be able to further voice the M1 and let it sing at lower frequencies. I sure hope so.

 

 

And You (of course) don't refer us to the actual review of the NAD M22 you are slagging (also by Kal Robinson), which concludes:

 

Quote

Conclusions
Overall, NAD's Masters Series M22 power amplifier acquitted itself with distinction. Despite its small size, it has all the wallop necessary for staggering volume levels, and, if necessary, can be bridged to meet even more outsize demands. At $3000, the M22 is more than fair value in view of its compact size, excellent build quality, a tolerance for driving difficult loads, and, most of all, its transparent sound. It is an outstanding amplifier in every way, and I could happily live with it.

 

 Or JA's conclusion of his measurements report on the M22:

Quote

NAD's Masters Series M22 amplifier measures extraordinarily well. It is the very model of a modern class-D amplifier!—John Atkinson

 

 

Let's see, who would I rather believe:  a troll like GUTB, or an extremely experienced reviewer like Kal Robinson, who participates here and actually tries to be helpful?  And KR,who has spent a serious amount of time reviewing the two specific amps GUTB brought to "prove" his claim that class D sucks. KR has  probably evaluated more amps of all classes than GUTB has actually heard. 

[firedog]

Sorry, these last few pages are mostly nonsense.

Techno gobbledy-goop for people trying to turn their personal taste in amps into some kind of objective truth. No decent Class D amp is harmful to anything and doesn't distort or mess with tweeters more than any other amp.

 

Here's the bottom line:

Lots of people - including pro reviewers, experienced audiophiles, musicians, etc., think the better ClassD amps sound fine and are a bargain - high level sound at more reasonable prices than many more expensive conventional amps that sound no better. They call the sound accurate and clean.

Other people think the same amps sound "clinical".

 

It's just taste. Audiophiles will never get consensus on any component. One man's "warm and natural" is another guy's "euphonic distortion"; one guy's "clinical" is another one's "accurate and realistic".

[firedog]

The short version: it doesn't matter with any of the audiophile designs. Just audiophilia nervosa.

[firedog]

1 minute ago, Shadders said:

Hi,

Ok- can you point to the link where this has been analysed that HF has no effect on the tweeter ?. Thanks.

 

Regards,

Shadders.

Hi-

Don't mean to be rude, but it seems you are engaging in armchair engineering on a subject that you know just enough about to come to unfounded  conclusions. The shoe is actually on the other foot: you are the one making  what in this context is an extraordinary claim, so the burden of proof is on you to show that it does matter - in any place other than your speculations.

[firedog]

4 minutes ago, Shadders said:

Hi,

If you read my original statement, it was a question whether this carrier frequency is the cause of all class D amplifiers sounding the same.

 

Regards,

Shadders.

Sounding the same? Acc'd to whom? They don't. Not any more than all class A, Class B, Class A/B. Look at the Hypex amps being sold now where you can switch the opamps on the board input - just that change makes the identical amp sound different. Audibly different.
I understand there are people that don't like something about the sound of Class D. That doesn't mean they all sound alike. Just like I prefer something about solid state to tube amps - it doesn't mean all tube amps sound alike.

[firedog]

6 minutes ago, Shadders said:

Hi,

No it is not. They have not stated what the impact is, which does not mean there is no impact.

 

They use a 22kHz measurement bandwidth for their THD in the data sheets - which is a bit of a con, where other amplifier manufacturers use 80kHz. They use 22kHz measurement bandwidth as it makes their THD look better.

 

Check out the specification for the NC500 and the review of an NC500 unit reviewed by stereophile :

https://www.stereophile.com/content/theta-digital-prometheus-monoblock-power-amplifier-measurements

 

Hypex quote 0.005% THD for 4ohms at 20kHz, yet the stereophile measurement is 0.08% - quite a bit different. More than 10x worse.

 

Regards,

Shadders.

 

As far as the Stereophile article, you just forgot to mention that JA said the higher distortion figures were only of "academic interest" and "The measured performance of Theta Digital's Prometheus is superb, even for an amplifier with a class-D output stage."
I trust JA and his measurements enough to think that if the amplifier was damaging speakers, he'd mention it.

[firedog]

4 minutes ago, Shadders said:

Hi,

I made no statement that the tweeter is damaged by the carrier frequency.

 

Regards,

Shadders.

So then what's the point of your posts? It doesn't damage the tweeter, you can't hear it, and they don't all sound the same....

[firedog]

48 minutes ago, sandyk said:

Incorrect. Many of Barry Diament's recordings have genuine musical content to >55kHZ, and his microphones are only 1dB down at 40kHZ. Just because we can't directly hear these frequencies does not mean that we can't hear their contribution.

I would also remind you that when Sony first introduced SACD they also sold 100kHZ tweeters to match the performance of SACD before it was dumnbed down shortly after. 

 

 Furthermore :

http://www.cco.caltech.edu/~boyk/spectra/spectra.htm

 

 

A segment from a new Barry Diament recording.

Your use of Barry's recordings is simply the exception that proves the rule. The poster you are contradicting was essentially correct-the large majority of  hi-res recordings don't have actual high frequency content, and many of the microphones used to record them don't even record at frequencies above 20khz, if that.

[firedog]

6 hours ago, sandyk said:

March Audio

You are making your signature look like a free commercial for the products that you sell which is unlikely to be permitted in this forum

His signature isn’t any different than the way Barrows and Jesus from Sonore sign their posts, including ones that aren’t in the Sonore forum.