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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
tweak1
3,645 posts
 
I was hoping to have some answers to that very question weeks ago
atmasphere's avatar
atmasphere
11,772 posts
 
Your
[sic]
twisting things to suite your self, I never ever said that you can hear these frequencies, I’ve always stated they have an effect and the "output filters used" in all Class-D amp to remove them have an audible effect, because they cause problems!!, and if the "output filters" are shifted up higher because the switching frequency is higher, then problems become minimized.
Hm. Your prior statements do not agree with the statement above. Here's an example- take a look:
GaN technology will finally get rid of these flaws of dead time and **switching noise**.
(emphasis added)
-what then, is 'switching noise', if not the residual??

In addition, as I pointed out before, most class D amplifiers use a 12dB slope in the filter. Now if you're up on your filter theory, you know that the phase shift artifact of a 12dB filter does not extend down to a 10th the cutoff frequency- that is a 6dB/octave filter that does that.

As for you getting abusive
I don't recall doing that and can't find any example of such in my prior posts. As you know, being abusive to another member violates forum rules. So I am quite careful in all my posts to avoid that! If you are referring to my prior post wherein this text occurs:
if you are saying you can hear 250KHz or 1.2MHz sine wave good luck trying convince anyone that you aren't a nutbag.
-that text is not abusive since I'm pretty sure that you are not in fact trying to convince anyone that you can hear to 250KHz or higher. If such is not the case, please let me know as that will be a bit of a surprise!

georgehifi's avatar
georgehifi
10,312 posts
 

There you go twisting things again.
  
The only interest you Ricevs and  Mike Mivera have coincidently in degrading anything to do with Class-D GaN Technology, is because it poses a big threat to all your yet to be released non GaN class-D amps. Which you all so delicately push here on these threads, except for Mike who got what seems to be a permanent sabbatical away from Agon for pushing too hard. 
atmasphere's avatar
atmasphere
11,772 posts
 
The only interest you Ricevs and Mike Mivera have coincidently in degrading anything to do with Class-D GaN Technology, is because it poses a big threat to all your yet to be released non GaN class-D amps. Which you all so delicately push here on these threads, except for Mike who got what seems to be a permanent sabbatical away from Agon for pushing too hard.
Sorry, don't know what you're talking about. I can't recall nor can you point to a post of mine where I've 'degraded anything to do with Class-D GaN Technology' as you put it. FWIW we've been working with GaN FETs for quite some time. IMO it makes no sense not to.
devilboy
1,176 posts
 
George, as I said in a previous post, you recently posted a list of manufactures poo pooing class D. I said it was because they see it as a threat to their non class D amps...... Which is exactly what you just said.
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