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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

Showing 4 responses by teo_audio

teo_audio
2,197 posts
 
I don’t have to try again, I nailed it in a nutshell.

The sign on the audio world door says ’pursuit of the finest reproduction’,

it does not say

’reproduction good enough for most to call it outside of their capacity to resolve as better or worse... and therefore the best possible.’
teo_audio
2,197 posts
 
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.

Retaining of the ear. The ear is mutable. Thus the retraining of the ear to deal with class d.

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

Yet, importantly..the Luxman with classic amplifier design, required no time at all to adjust to.

What does this tell you? It tells you that the Luxman is more natural and correctly addressing the ear’s natural function ---all in a way that the ear resolves sound.

The class D amp is a fight to get the brain to ignore it’s follies and have the brain ear combination attempt to find resolution hiding in the noise and distortion pattern that is foreign to how the ear works.

Why would any sensible human being be up for that?

That’s what it tells you. It tells you that the class d ’bear’ can dance in a way that the humans can recognize as being akin to a dance, but really is not a true and actual dance. Just similar. ’the bear looks like it is dancing’, in the same way, ’class d seems to be reproducing a signal’ Kinda sorta maybe. But not quite as good as other, older tech.

As the experience, when properly considered ...so clearly shows--- Class D is not more natural or better. So why fight with it for another 20 years so it can get closer, when you are already there with another technology?

It’s like saying, "I can row my boat across the lake really really well..so now I’m going to cut my arms off and do it with stumps. And I’ll eventually, maybe, somehow.. be good enough to win the Indy 500 of boating. And finally be back to where I was at, before I cut my arms off."  

The logic and thinking is dubious at best and insane at the worst.
teo_audio
2,197 posts
 
That’s true, but it might open another bag of worms. In current designs filter leaves about 1% of switching noise on the speaker cable. It is only small percentage but of very high value, reaching 100V - making it approx. 1V peak switching noise on the cable. It can be easily seen with the scope. The only reason why it does not radiate is the fact that 500kHz wavelength is 600m. Antena becomes very ineffective below 1/10 of the wavelength - in this case 60m. There will be still some, very small electromagnetic radiation but it should not be a problem. Increasing switching frequency, let say 10x will make this antena "dangerous" at 6m, producing some radiation even with regular speaker cables. It is possible to filter it better, but it would lower bandwidth resulting in phase shift in audio band, that we want to avoid. Perhaps compromise is somewhere in-between, increasing switching frequency only 2-3x while still enjoying improved linearity thru reduction of dead time.
I can hear that residual noise as a forming of hash and noise around every single transient, micro transient and complex harmonic.

Basically, class d loses the idea of high fidelity as all of high fidelity happens in that exact spot mentioned. the rest of the signal is almost meaningless.

So i spend a lifetime trying to fix that tiny little bit and class D comes along and maims to death the very part I and other in the realm of high fidelity seek and fight for.

This noise can be mistaken by some people as detail, when it is actually noise and out of band, out of time ---- added distortion and noise.

worst of all, in the modern realm of digital audio, A/D and D/ A systems also cause massive disturbance right in this area of signal.

This means you now have an entire generation of people who have NO IDEA how good analog can sound and generally does sound, when this part that digital does wrong, is absent in the signal.

Then, this lack of knowledge and exposure to what analog does right, is then aided and abetted by the hash and junk that Class D adds in on top of that. this whole mess is somehow regarded as muddy and fatiguing ’detail’, where it all sounds the same. Because it is.

this is like some freaking nightmare world. You’re kidding me, right?
teo_audio
2,197 posts
 
This example suggests that it is far better to form opinion after listening to particular amp than making blank statements about whole class D.
I’m making blanket statements about all of class D for a reason.

A strong, stable, intelligent set of reasons. As in none of them ..class D, that is...performs. Nether in the listening, the engineering, or the execution (build).

It is still a turbo on a Honda civic --- trying to pose as a formula one car. As that is it’s origins. It was never meant for formula one use, never designed for it, at all. Never intendedd for it, no part of it's engineering or potential in build approaches what is required for such highfalutin use.

When the market involved finally has one that is engineered and manufactured properly, that works in a way that satisfies how the ear works and functions---- then get back to me (us).

Maybe in about 3-5 years. Maybe. No such luck yet.
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