The Truth about Modern Class D

This thread is now a closed time loop of condescension and claims without evidence or logic.

Lets have it closed and stand as a monument to the character of the contributors.

Hmmm, just wondering if it is OK if I continue to enjoy the performance of my Bel Canto amp in my system.

@mlsstl 
To hear George tell it, you have to put it on a test bench, and after looking at the scope's output, you'll suddenly realize ....

I don't know what. Actually I have no idea what his point is.

@georgehifi

Looking forward to your complete retraction of your false claims regarding Class D and output phase.

I will be kind and suggest that you going "wow, I'm sorry, that was incorrect" is going to be a lot easier on you than me writing up a post about why it's wrong.

Really, fixing your own mistake is going to give you character.

Kisses

And I didn't revitalize ****, it was a 2 poster markw1951

Hahahahahaha. 

- Quote me.

I don’t know George, you are swearing, resorting to personal attacks and failing to answer your technical mistakes.

Maybe bashing Class D all weekend long isn’t your most productive use of your time??

BTW, George, thanks for helping to revitalize this thread. I haven't seen it for months, then 1 new post shows up and your incessant bashing Class D keeps this thread at the top of the list for Audiogon.

This would be a dead thread if it wasn't for you.

Kisses

Wow what a rant, clean up aisle 4

@georgehifi

Looking forward to you recognizing your technical errors and retracting them.

yes you are known as an Pass Labs basher

George, you have bashed Class D more in the first page of this thread than I ever mentioned Pass (the name or the brand). In fact, all over Audiogon, one cannot mention Class D without you jumping in. You are exactly like Beetlejuice (the movie).

So, in this thread, recently, you’ve failed to recognize your technical mistake, took a condescending attitude towards another audiogoner and insulted me, also, you’ve lied about me. Talk about a lack of respect.

I am looking forward to the time when you are shown the technical errors in your argument and you actually don’t turn it into an excuse to attack another.

Kisses

Golf, that **** doesn’t worry me, I just hope the mods see it and treat it for
what it’s worth. He’s a Nelson Pass basher, we all know it.

So, @georgehifi you had a post of mine which laughed out loud at you removed because you felt it was too insulting and classless, but calling another member an idiot is OK? Also, if you are talking about me, George, I have never bashed Nelson Pass, and I daresay I have never bashed the brand. I don’t like it. I’m allowed to not like something, right? Because god knows you have half the posts in this thread talking about Class D being terrible.

Also, relevance?

I started this thread hoping to get members to be open minded and let those who enjoy Class D chime in. Instead it has become a character study. Anyone who takes you at face value should read the entire thread. I stand behind my behavior.

Best,

E

There's a handful of people on A'gon who need Class D amps to fail, and then there's dozens of us who enjoy it every day.

:)

Erik

Once you’ve made your point, time to move on, but noooooo. Seems like every time someone posts something positive, you have to rush BACK in and spew your ’knowledge’, for which people who actually understand the electronics, have to correct you, yet again

@tweak1 :

To use GFi’s exact condescending words against him: "You just doesn’t get it, george."

@georgehifi

Oh wow, for some one who routinely attacks other A’gonners personally you are very very sensitive fellow.

So, lets stick to facts:

You just don’t get it tweak, this is why many find the upper mids/highs objectionable on Class-D, why would I want to listen to an amp with this much phase shift already 25 degrees! at 2khz, and it get’s progressively worse all the way up to 70 degrees!!! at 10khz.

You are completely misreading the data you posted.

As I posted before, the chart you are showing is the phase angle of the output impedance, not of the audio signal. Look at the datasheet for the 250 ASP, which actually shows the phase angle of the audio signal itself.

As I also posted before, most experts agree that phase angle doesn’t mean that much, so even if your horrific misinterpretation of data was accurate (and it is factually wrong) I doubt anyone would hear it.

https://audioxpress.com/article/zero-phase-in-studio-monitors

Some one who had integrity would strive to correct errors of fact when possible, instead of attacking the character and taste of those who disagree with him.  Please, show us your mettle.

Kisses.

I've never heard either. :)

I believe your experiences. I just want to caution people to avoid judging all Class D on one experience.

It's been rock-paper-scissors for me. There are some class A amps I like a LOT less than my last Class D.

Best,
E

Regardless of how well designed the amplifier is, there will be loads with which it will not mate well.

Which is true of all amplifiers. The output impedance of amps without any output filtering at all is far more complicated, and the output impedance of tube amps is RL as well.

Which goes back to my original point that Class D amps are not stand outs in output impedance anymore. You have to listen for yourself.

There are a lot of tube amps which do poorly with ESL speakers, for instance. Linear SS amps tend to do better, but not in every case. Class D is somewhere in there. Depends on the specific implementation.  Despite this, there are a number of audiophiles who end up running tube amps with ESl's. Technically I'd be surprised if the Class D amp didin't measure better.

It is prejudicial to be comparing Class D in bulk with mega linear amps at all times. Lets be more realistic.

Hey @jdl57 - I have heard the effects you are talking about in a number of hotel rooms. It was poor room acoustics.

IMO, one should examine the cable/speaker impedance curve when choosing ANY amplifier. Class-D can be more sensitive due to the low pass filter.

It is true that knowing both behaviors is important, however Class D output impedance is well within the range of high quality Class A/B amps with feedback.

The Class D amps I am most familiar with have lower output impedance than most tube amps, but probably not as low as some beasts like the Codas or Sander’s with their 30 transistors per output channel. :)

Keep in mind a lot of linear amps have a low pass filter on the output to prevent oscillation. Then there is the Technics amp which actually measures the speaker impedance and compensates for it with DSP. Pretty nifty.

Best,
E

Again, calling all Class D amps the same, or blaming them all for the failings of one specific model is just prejudice.

@jdl57 - I've run much less expensive class D through incredibly revealing speakers and not heard the problems you experienced.

Best,
E

What I like most about this thread is the clear difference between those willing to give Class D a chance and detractors.

Those who are neutral to positive are talking about specific brands, and models and making direct comparisons with linear amps. They talk about sound quality, systems and trade offs.


Those who are against Class D are talking about tropes from the 1980's, and measurements and broad claims that become impossible to test.

It WILL NEVER be as good as tubes,class a or good a/b NEVER!!!

Disco is NOT dead! Disco is life!! - Tony P., Mystery Men

@celander 

Thanks, bud. 

That was some of the most ridiculous and inappropriately placed piece of snake oil selling I've seen in a long while. 

Best,

E

The truth is class D is totally mediocre.If you think its great jump on an amp ASAP!!!!

 Report this
@ebm 

Blanket statements like this, without qualifying them with your experience, and speakers used are entirely unhelpful. Want to fill this in with what you find not-mediocre, and what Class D you have heard? 

Best,

E

It’s simple. You cannot put anything into the air besides a hot air balloon. At best you can create a glider and glide down from above, but the idea that you could build a machine heavier than air that could hold a person a motor and fuel combined is ridiculous.

Just think of the weight of the fuel alone! Gasoline weighs over six pounds per gallon. To have enough gasoline to push against the ground with a motor or fan of some sort would require monstrous gasoline consumption.

It is utterly ridiculous to imagine that you could do anything useful with a machine and flight. The machine itself, the motor, the fuel and the pilot simply are not sustainable.

Not only is it physically impossible, but dear god, it’s a foolish venture to attempt to make such death traps into a business. You could never produce an actual plane that could carry itself for long, let alone cargo, people, or get anyone to pay to have the gargo moved that way. Anyone who shipped via an airplane would surely loose their valuable posessions that way.  And comfort? What kind of comfort could you experience from falling out of the sky?

No, sir, no. It is clear that rational human beings should stick to balloons.

Unfortunately, this book is now out of print, but I think it would remind us of where we are :

https://amzn.to/2M0bBLB

I flew into the LA airport this morning. I saw a guy outside with a sign: 

"Planes can't fly!" 

I said "Hello, George." 

I think both switching speeds and dead time have yet to be shown to lend any particular character to any particular amplifier.

Prove either is audible and unpleasant first. Then you might get me to care about either. 

The problem is not dead time, or notch distortion. The problem is audibility and connecting that to any particular technical choice. 

What I mean is, all amplifiers, even all musical instruments, have "flaws." To some they may not be flaws, to some they may be "attributes." We can argue about them forever but the importance of any flaw has to do with it's audibility. 

We can talk about ways to mitigate "dead time" forever, but that does not make the issue audible. 

One thing that Revel and Bose both do incredibly well is to pay attention to technology not for it's own sake but for audibility and desirability. We could learn from these approaches. 

Best,

E

While there are a lot of logical mistakes we can make, what I cannot argue with is listening. 

Buy what you like. 

helomech - 

So you heard Parasound and Devialet amps on Magnepans and did not like the Devialet. 

That is 1 single sample of a specific Class D amplifier you did not like. Is that correct? 

Erik 

@helomech I’ve had Parasound Halo amps. I traded them for ICEpower amps which in my environment sounded equivalent.

Can you tell us about the speakers you evaluated with when you say the Parasound took the Devialet to school?

PS - I like Parasound a great deal. This is not about trashing them.

There are certain things I cannot argue with. Personal choice for specific amplifiers and speakers. That’s fine.

My argument was not "you should like Class D more than your favorite" but that Class D as a whole is just as good as capable and musical as any other solid state amps, with a lot of the same pitfalls. The technology has in fact arrived for good, and we are better for it. 

Does that make me a horrible person because I don’t like them? I enjoy the lush romantic sound I get from Mac and since I am spending my money on it, what I like counts (to me).

Absolutely not. But the specifics help everyone understand where you are coming from and what you are comparing to, and give a lot more insight to your story.

My NAD D 3020 is hooked up to a pair of Monitor Audio, which are much more laid back, which may explain the difference in appreciation for it. :)

As I myself have noted, if I had all the $$$ and space I’d buy some CJ which are going to be even more euphonic than your Macs. I still like my ICEpower monoblocks though. I certainly could not point to them and say "look, Class D sound!" 

Thanks for sharing,


Erik

@stereo5 -

I’d suggest you make your specifics known. What Class D and what are you comparing it to?

Because the ICEpower I’m listening to sound nothing but warm. The NAD D 3020 sound a touch brighter, but not unpleasantly so.

There’s nothing in your original statement specific enough for me to believe you are being sincere. If you are, state your experience.

I could say the same about tubes. "Tubes are not high end, but maybe someday..." 

Because they still apply today, but there’s light on the horizon

This is, in fact, too ridiculous to satire.

I have no time to read your comments, but to show my respect I am going to paste a long lecture here on what I think on the subject.

The Squires method is superior in every way to any previous method. In terms of refinement and air and presence, the Squires method just cannot be compared to any other method.

It has on occasion caused premature births however and needs to be used with caution. Also lights in your room may shift slightly red, undetectable to most. If you aren’t paying attention you will absolutely miss it.


<< rolls his eyes >>

I would like to explain to everyone why heavier than air flight is impossible, you cannot transmit radio signals across a vacuum and transistors will never be useful. Bear with me as I gather the relevant quotes.

@georgehif - You should start your own magazine, because even though you don't like Class D you are in every single discussion about it. Call it: 

"Why I can't move past 30 year old arguments." 

Best,

E

Old school, get professional help from GIK,

and don't neglect the flooring, between and behind the speakers. Try using pillows and blankets to test with for free.  :) 

Best,

Erik

audiothesis : 

Aha! :) 

I knew you were one of those OTL scoundrels! 

J/k : But the truth is if OTL is what you like, then talking about good Class D amps is not going to be your cup of tea.

Best,

E

@timlub 

Parts Express is now selling ICEpower modules directly and for cheap. :) 

Best,

E

@stereo5 Then consider me one of the lucky one’s.

Sighted or blind, I cannot hear a difference between them an Parasound A23s. None. Zero. Nada.

So, since it is my wallet and tastes that pay those bills, I’d rather go with the more energy efficient one.

And in fact I prefer the sound far over and above the sound of Pass. Same for Parasound vs. Pass. :)

But it isn’t because of anything I can hear as "class D sound."

You don't have to like a particular amp, but I think being dismissive of them as a class is short sighted.