What’s the big deal with class ‘D’ anyhow ?

[AJ Soundfield]

I'm sure lots of people would like to know the answer for how much it will cost to equal the sound quality of expensive Class A amps with Class D such that no one can tell them apart.

Why would cost matter to a real subjectivist? Cost is unequivocally an objective metric. There is nothing subjective about a number at all.
Cost as a number/metric would be critical for a purely objective individual. For a subjectivist, the only thing that matters is how it sounds, maybe looks.
Who is this amp for, a so called objectivist or subjectivist?
Of course, what sound generating speaker/load would certainly matter when recommending anything.

[Devg]

Anybody heard the Cherry Amps ? They are also Class D and some over at AC thinks they are the best Class D amps available in the market today.

[mep]

Why would cost matter to a real subjectivist? Cost is unequivocally an objective metric. There is nothing subjective about a number at all.
Cost as a number/metric would be critical for a purely objective individual. For a subjectivist, the only thing that matters is how it sounds, maybe looks.
Who is this amp for, a so called objectivist or subjectivist?
Of course, what sound generating speaker/load would certainly matter when recommending anything.

Cost always matters to people. If you get up on a soapbox and proclaim that a $5k or $10K pair of Class D amps are indistinguishable from Class A amps that cost $20K and up to no limit, you might interest people in your personal feelings. The truth is that all amps sound different. Do the Class D amps that you are high on all have linear power supplies?

[jadedavid]

I have heard the Cherry amps in a friends system. Very clean, clear and fast but seemed to lack "soul"(IMO).
The owner did change them out to a Valvet E-2 class A amp and found it to be much more involving.

[AJ Soundfield]

Cost always matters to people.

Of course, including pseudo-subjectivists where it matters greatest. They are unable to judge with their ears and must rely on objective metrics like cost, power supplies, parts, etc. I agree.
A perfect example of why cost matters most to some is here

If you get up on a soapbox and proclaim that a $5k or $10K pair of Class D amps are indistinguishable from Class A amps that cost $20K and up to no limit, you might interest people in your personal feelings.

The results of my blind tests aren't personal feeling. The impact price tags have on certain individuals is personal feelings.

The truth is that all amps sound different.

A zero evidence "truth". Quite vogue these days. (not to mention the obvious fallacy of having heard all amplifiers.)

Do the Class D amps that you are high on all have linear power supplies?

Audiophiles get high on amps. I see them as commodity parts. A, AB, D, etc. As long as they are good, don't care about class.
I leave illicit relationships with inanimate audio equipment to audiophiles.
The D amps I refer to use both linear and smps...again, commodity parts to me. I care only about sound.

[a.wayne]

This is exactly the type of person that I tested, who raved about the "live music" sound of the Class A amp they were looking at....when in fact their ears were hearing Class D.
I must be missing something, but I don't see a name on that review. I would love to put his face on Youtube, where he easily identifies the Class D vs Class A sound that exists in his mind, when he doesn't know which he's listening to. Would be fun.

Expose the scoundrel .....

[a.wayne]

When they are equally capable of driving the load without exhibiting audible non-linearities, of which there are a great many metrics. Frequency, distortion spectra, compression, noise, etc, they become increasingly difficult...or impossible, to distinguish via ears.
The "class" matters scant then. Easier said than done, but also easily demonstrable.
Hence my Youtube suggestion. Have the claimant pick whichever non-pathelogical class A (so no SET etc) they believe best highlight the attributes that will allow differentiation vs Class D, I'll supply the Class D and the camera. The whole world gets to see the results of the claimant.

Class-D claimant if proven wrong gets a public flogging for the world to see just how dangerous class-D ownership can be ...

[AJ Soundfield]

Expose the scoundrel .....

Sure, acceptable view. But from my perspective, it's the ultimate sound test of the amplification for my speakers, a "trust your ears only" version. It would do me no good to put amplification in my speakers if they truly sounded like what the detractors claim. I can't think of a better way to test that...and there were many a class D detractor swooning over the "class A" sound.
I have zero control over audiophiles belief in poor class d sound, silver, vampires and whatnot, so I focus on what I do have control over...the sound.

Btw, regarding cost, there is overwhelming scientific evidence that higher prices make some folks happier
http://time.com/4902359/wine-tastes-...it-costs-more/

“Our findings also show that high price tags (within a range of acceptable qualities) makes you happier,” he says, “so you get what you pay for.”

So indeed, if paying $100k for an amp makes you happier and the music more enjoyable, buy it.
Just please skip the absurd objective reasons, when it's a purely subjective matter.

cheers,

AJ

[AJ Soundfield]

Class-D claimant if proven wrong gets a public flogging for the world to see just how dangerous class-D ownership can be ...

Always a possibility despite my extensive tests.

[deangale123]

This is exactly the type of person that I tested, who raved about the "live music" sound of the Class A amp they were looking at....when in fact their ears were hearing Class D.
I must be missing something, but I don't see a name on that review. I would love to put his face on Youtube, where he easily identifies the Class D vs Class A sound that exists in his mind, when he doesn't know which he's listening to. Would be fun.

Isn't the goal to really not know " What" class of amp your listening to? Only to hear the music in all it's glory, power , subtleties without the coloration of said amp.

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[AJ Soundfield]

Isn't the goal to really not know " What" class of amp your listening to? Only to hear the music in all it's glory, power , subtleties without the coloration of said amp.

Yes, for a true subjectivist, only the sound matters. They trust their ears. Not the price, class, power supply, distortion profile, silver wiring, weight and 1000+ purely objective parameters.
For others, all those objective facts are what matters most.

[mep]

Yes, for a true subjectivist, only the sound matters. They trust their ears. Not the price, class, power supply, distortion profile, silver wiring, weight and 1000+ purely objective parameters.
For others, all those objective facts are what matters most.

You should go into business with Ethan Winer. You two would make a great pair.

[AJ Soundfield]

You should go into business with Ethan Winer. You two would make a great pair.

Nah, we're on opposite ends of the spectrum when it comes to sighted beliefs vs perceptual science http://www.audiocircle.com/index.php?topic=123167.20
I do like his video with him tied to that chair though.

[a.wayne]

Isn't the goal to really not know " What" class of amp your listening to? Only to hear the music in all it's glory, power , subtleties without the coloration of said amp.

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Which amp is this , you know the one without coloration ..? Class-D ..!

[a.wayne]

Nah, we're on opposite ends of the spectrum when it comes to sighted beliefs vs perceptual science http://www.audiocircle.com/index.php?topic=123167.20
I do like his video with him tied to that chair though.

But can Class-D strap you to a chair .....

[deangale123]

But can Class-D strap you to a chair .....

Nah, no bias here.

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[deangale123]

Nah, no bias here.

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Sorry pinned the wrong comment , my apologies.

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[a.wayne]

Is class -D "dead " ....???

[Randy Myers]

By all accounts Class D is becoming more popular. I am very happy with my new Class D mono amps. They sound amazing! They have also received several great reviews.

[a.wayne]

What Brand Class -D .....

[Dizzie]

What Brand Class -D .....

Check out Randy's equipment list in his post.

[Randy Myers]

What Diz said... or PS Audio M700's.... whichever is easier for you ...

[Kingrex]

AJ, what amp are you using for the test. I think MEP, has a point about price. If Incandescent purchase a $2,000 amp that is indistinguishable from any other amp regardless of price, well.

You also talk a big story about blind test. I can use a blind test to trick your mind. In other words, I can shape a test so that your mind now tells you what you are hearing is wrong. For example, I never put the put the class A back into the test. I just keep playing the class D. Eventually your mind will tell you you hear a difference because you have been told there is one.

How exactly do you perform the test and have you done the test as you will explain every time. Please include time exposure. Also, are you doing the test on the listeners equipment. I assume Inwould test much higher at my own home as the source, preamp, speakers are very familiar and Inwould not be listening through all the unknown sounds to me.

Remember, amps are not in a vacuum, they are part of a system. Synergy is important.

[Kingrex]

https://www.stereophile.com/content/...ring-sound-qua

[Kingrex]

Read the link I posted above to understand more about what a blind test may or may not reveal.

[AJ Soundfield]

AJ, what amp are you using for the test.

No need to know unless you have zero trust of ears.
You can either tell by trusting your ears, or you can't. Which is it?

https://en.wikipedia.org/wiki/Blinded_experiment
Please read the link above for why blind tests exist.

If you don't listen blind at home and enjoy the looks, price, street cred, bragging rights, "Class", beliefs etc, etc, etc. about your audio system, then there is no need to go further. Blind tests are for a specific purpose. In the case of what I'm referring to - sound and sound only. Trust only ears, nothing else. YMMV

[Kingrex]

You need to do a deep address about what a blind test is. See my link. Really a blind test can be a bunch of BS. If you want me to trust my ears, your blind test needs to be done in my house. It needs to be done with my stereo. It needs to be done with my reference recordings. Done this way I will hear the differences. Now there is the opportunity for me to make a personal subjective opinion about whether I like what I hear or not. That opinion may be based upon preconceived bios. My only point is it in my system with my music I will hear the difference. In a blind test there are all sorts, let me repeat that, all sorts of variations that can dramatically impact what results you will get from the test. This article doesn't go so far but my studies in sociology and psychology also point to the ability to shape an outcome the way you want it to happen with testing procedures. For these reasons I find a blind test on an unknown system with Unknown music means little.

[Speedskater]

No need to know unless you have zero trust of ears.
You can either tell by trusting your ears, or you can't. Which is it?
...........................................
Blind tests are for a specific purpose. In the case of what I'm referring to - sound and sound only. Trust only ears, nothing else. YMMV

Exactly!
If you have to use your eyes, that means that you don't really trust your ears.

[AJ Soundfield]

Really a blind test can be a bunch of BS.

Of course, there can be poor blind tests. But there are good ones too. Hence they remain the defacto standard of science and the bane of belief.

If you want me to trust my ears, your blind test needs to be done in my house. It needs to be done with my stereo. It needs to be done with my reference recordings.

Sure, as soon as you move to FL I'll be right over

For these reasons I find a blind test on an unknown system with Unknown music means little.

As I said, that is only for those who trust their ears, not those who don't. I've done countless ones outside my home, so I'm comfortable trusting my ears with sound, not while viewing my home and equipment. Otherwise, how the heck would I set up systems/speakers anywhere else? Luckily, folks in the AES/Harman/Pharmaceutical industry, etc etc can find lots of volunteers so you can enjoy the benefits of your medications, use your cel phone, etc, even though you might prefer they all come to your house to test.

Btw, a Stereophile link from its founder https://www.stereophile.com/asweseei...wsi/index.html

[Kingrex]

Exactly, you have done countless test outside of your house. You have been trained on how to make a proper evaluation. The average consumer has not.

Now the comment I made about doing it in my house, is not necessarily accurate at all. What would be accurate to say is for there to be a blind test one must truly evaluate what you are trying to test and whether the parameters of the test are designed to seek a result that validates what you were attempting to test for. That's a little muddy in statement but I think you get what I mean. This testing procedure should be reviewed and agreed upon by many people to weigh the pros and cons of how it would be performed. Walking into some situation that you think is good may not be good at all. You may have designed a test with parameters that are designed to intentionally deceive people. That is all fine and dandy that you can trick people, but it does not mean that under appropriate test conditions the average person could not tell the difference between a Class D and Class A amplifier. That is the test and the parameters need to be carefully put together to know that you are actually testing for that result.

As I have asked a couple times, a thorough briefing of how you perform a blind test is necessary to understand whether your comment of a a/b blind test is valid or not. You seem to not want to share that information. Until you share that information there really isn't much to discuss with you anymore.

I don't mean that as an insult. I'm not trying to be a troll in any way. I myself am always interested in the outcomes of a real scientific test. I have been doing many myself to understand the power from my wall and how best to optimize it. I'm excited by anybody else who can truly put together a validating system that allows audio file to know more better what equipment they're getting and the value for the money they put out. If you can share with us the testing parameters that helps everyone to feel comfortable that the results are actually validating a specific claim then we would all be pleased to see the test

[AJ Soundfield]

What would be accurate to say is for there to be a blind test one must truly evaluate what you are trying to test and whether the parameters of the test are designed to seek a result that validates what you were attempting to test for. That's a little muddy in statement but I think you get what I mean.

I took what you said originally as wanting to remove as many variables as possible - so we are not in disagreement.
But then might also be a tacit admission that any differences being sought are elusive and perhaps very subtle indeed.

As I have asked a couple times, a thorough briefing of how you perform a blind test is necessary to understand whether your comment of a a/b blind test is valid or not. You seem to not want to share that information.

Because my intent wasn't to embarrass a whole lot of folks. It was to answer a specific question, which is can a large number of audiophiles who might claim differently, actually hear the differences they claim, when they don't know they are listening to a modern, highly competently filtered and designed Class D amp. Maybe seeing (and sometimes hearing) a Class A amp instead.
From purely a sound point of view, that gives me confidence to use them in my products. I am not saying knowledge of them in my products can't/won't cause melodrama. But I am confident it won't be because of sound.

If you can share with us the testing parameters that helps everyone to feel comfortable that the results are actually validating a specific claim then we would all be pleased to see the test

As I've said many times, I don't listen blind for enjoyment, away or at home. As such, I enjoy looks, feel, etc, etc, etc like everybody else except those who would rather lie to themselves. So have no issue admitting I've bought amps and whatnot just because they look great...to me.
If you are looking to answer a very specific question like specific sound of class A vs D, a blind test is dictated by science. If you're looking to find whether you like the widget, sight, sound, feel, etc, etc, etc. kicking back listening in the easy chair at home, then no blind test is needed at all. Ever.
The end.

cheers,

AJ

[Kingrex]

I assume you're not in Miami. I was just there two weeks ago at the Audio Salon, Deja Vu, and I'm sorry I spaced out the name of the other place but Felipe was very kindly showed me the boulder amplifiers. What part of Florida is your store in. I'm going to be there again in November and always like to hear nice systems?

[AJ Soundfield]

I assume you're not in Miami. I was just there two weeks ago at the Audio Salon, Deja Vu, and I'm sorry I spaced out the name of the other place but Felipe was very kindly showed me the boulder amplifiers. What part of Florida is your store in. I'm going to be there again in November and always like to hear nice systems?

Nope, Tampa, just like it says under that picture of George Clooney.
No storefront, yet. Working on something for early next year though.
But that brings us full circle. Unlike an amp, cables, source, etc, loudspeakers, being the only soundwave generators, are absolutely critical to hear....yup, in your room.
Working on that too. Unfortunately a company in the Netherlands has delayed for well over a year now, me completing some "touring" pairs for exactly that purpose. We can talk about class D, total controlled polar response, cardioid bass, indirect diffuse decorrelated radiation, all remotely controlled, etc, etc....but its another thing entirely to hear it all from your own easy chair. I hope we can agree on that.

cheers,

AJ

[Smile]

If you can share with us the testing parameters that helps everyone to feel comfortable that the results are actually validating a specific claim then we would all be pleased to see the test

What testing parameters do you believe provide valid results?

[Randy Myers]

All of this aside.... to me, sometimes it comes down purley to the feeling you get from certain pieces of your gear. Take for example my PS Audio M700's. I have no rhyme or reason to it, and they sound amazing, but they just don't give me that warm and cuddly feeling. My pre-amp does, my DAC definitely does, my speakers very much do.... and I know that unless I get something massively more expensive the chances of getting improved sound is minimal, at best.

I do still long for tubes.... no idea why... but also miss the First Watt. But sound quality, I would say the M700's may very well be as good as any I have owned...

Amps I enjoyed the most through my discoveries are:

* the ARC VT-50. Love the build of this amp, but was a bit mushy sounding compared to more modern amps.... decided it would not be my long term solution....
* the Job 225 (twice).... just did not feel it was my long term solution, but really love that little amp...
* Quicksilver Silver 88's... really like the design and sound, but they were far too finicky in my system (may have been something just not "right" with the amps themself)

I was seriously thinking of getting some new Quicksilver's, but really think I want to stick with Balanced since recently upping my game on balanced cables. Wish I could get my hands on the Job Mono's.... still can't believe that Goldmund stopped making them ....

So anyway, Class D, what I am using as an excellent example, really hold their own in sound quality. I can honestly say that I know I couldn't have picked any of the others as better sounding without some serious serious side by side back and forth, and then the M700''s may very well have won.

But, they just don't give me warm and fuzzies.... and I don't know why. Design wise, seem very well made.... solid built, love the bi-wiring capability, which I use...

For me the M700's have far too much power.... To a point that I have to set HQPlayer at -20db output so that I have more control at lower levels from my pre-amp. I could set the DAC to use it's volume control instead of bi-passing it with the line switch... Not sure which way would be better actually, setting lower output on HQPlayer or using the DAC volume to turn it down a little (opinions on this one are very much welcomed).

[deangale123]

I would definitely lower the output of your day unless it is digital volume. If so sure shave a bit off, say 3db but I wouldn't go lower .

All of this aside.... to me, sometimes it comes down purley to the feeling you get from certain pieces of your gear. Take for example my PS Audio M700's. I have no rhyme or reason to it, and they sound amazing, but they just don't give me that warm and cuddly feeling. My pre-amp does, my DAC definitely does, my speakers very much do.... and I know that unless I get something massively more expensive the chances of getting improved sound is minimal, at best.

I do still long for tubes.... no idea why... but also miss the First Watt. But sound quality, I would say the M700's may very well be as good as any I have owned...

Amps I enjoyed the most through my discoveries are:

* the ARC VT-50. Love the build of this amp, but was a bit mushy sounding compared to more modern amps.... decided it would not be my long term solution....
* the Job 225 (twice).... just did not feel it was my long term solution, but really love that little amp...
* Quicksilver Silver 88's... really like the design and sound, but they were far too finicky in my system (may have been something just not "right" with the amps themself)

I was seriously thinking of getting some new Quicksilver's, but really think I want to stick with Balanced since recently upping my game on balanced cables. Wish I could get my hands on the Job Mono's.... still can't believe that Goldmund stopped making them ....

So anyway, Class D, what I am using as an excellent example, really hold their own in sound quality. I can honestly say that I know I couldn't have picked any of the others as better sounding without some serious serious side by side back and forth, and then the M700''s may very well have won.

But, they just don't give me warm and fuzzies.... and I don't know why. Design wise, seem very well made.... solid built, love the bi-wiring capability, which I use...

For me the M700's have far too much power.... To a point that I have to set HQPlayer at -20db output so that I have more control at lower levels from my pre-amp. I could set the DAC to use it's volume control instead of bi-passing it with the line switch... Not sure which way would be better actually, setting lower output on HQPlayer or using the DAC volume to turn it down a little (opinions on this one are very much welcomed).

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[deangale123]

Dac , Dac bloody auto correct

I would definitely lower the output of your day unless it is digital volume. If so sure shave a bit off, say 3db but I wouldn't go lower .

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[Randy Myers]

Hehe, love auto correct .... I believe the T+A has a resistor ladder analog volume section.

[deangale123]

Hehe, love auto correct .... I believe the T+A has a resistor ladder analog volume section.

Then I reckon your better off reducing it to the desired level e.g. the source.

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[Jack]

Randy

With the ARC having 18db gain in balanced mode combined with the M700's input sensitivity of 1 volt (only slightly higher than the Job) you indeed have an imbalance. The two ways to "fix" are to lower the output level of the DAC or use the Rothwell's again. I guess a third option would be to reduce output level in Roon.

[Randy Myers]

Yea, reducing it in HQPlayer is the same as lowering it in Roon .... but I am thinking that with a resistor ladder volume in the DAC this would probably make the most sense... I have the Rothwell in SE, might have to grab some in XLR.... good thing to have around anyway...

[deangale123]

Well there are balanced inline attentuators, but I don't know there quality . I actually use them for my subs to overcome the usual boost deployed in the 40 - 50 Hz level.

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[Randy Myers]

The Rothwell's are very good, but they are out of the UK, so not quite as easy to get... last time I bought some straight from them.... Might have to do the same thing...

[Jack]

I own and have used both the SE and Balanced versions of the Rothwell's with multiple amp preamp combos and have never noticed any sound degradation. There is another option, Harrison Labs, but they are SE only.

[Mechnutt]

Randy, are you using XLR's or SE? If XLR's try switching to SE as you will loose about 6db. It may help a little. I can tell the difference in my system.

[Randy Myers]

I do prefer XLR, and I recently got some fairly decent XLR cables... so I prefer sticking with XLR. But a good thought for sure.

[Jack]

Randy

Understand that you prefer the XLR cables but I would try it with the SE cables as an experiment to see if it works then you will know for sure whether or not the Rothwell's will solve the problem without doing it on the software end. I have only gone to all XLR cables recently as that is how the DSD and the BHK gear is set up to operate to full potential.