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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
gillatgh's avatar
gillatgh
381 posts
 
A tidbit for the anti D crowd, recently a friend who has been out of town came by for a visit.  We used to jam quite a bit and he did not know my Krell Kav 250 died and is temporarily replaced by an Emotiva Gen3. While jamming he exclaimed that my sound was the best he's heard yet. Go figure. He still don't know it's class D. All his amps, yes multiples, are class AB and sound fantastic.
Maybe he's getting hearing problems, but if so I must be too. The plan, when the Krell died, was to get an inexpensive amp with lots of power, then save for a parasound halo but now I'm more inclined to try a better class D such as Dsonic
True story
georgehifi's avatar
georgehifi
10,312 posts
 
A tidbit for the anti D crowd, recently a friend who has been out of town came by for a visit. We used to jam quite a bit and he did not know my Krell Kav 250 died and is temporarily replaced by an Emotiva Gen3. While jamming he exclaimed that my sound was the best he’s heard yet. Go figure. He still don’t know it’s class D. All his amps, yes multiples, are class AB and sound fantastic.
Sorry to burst your bubble gillatgh, I maybe wrong, but for memory I think you’ll find all the Gen 3 Emotiva’s amp are linear Class-A/B driven from Class-H power supplies.
They make a cheap $300 budget Class-D called the PA1, PA standing most likely for "Public Address" amp.

Cheers George
toetapaudio
474 posts
 
@georgehifi, you really must go and listen to some amplifiers before giving opinions. As @ricevs says there are many factors that add up to influence the sound of an amplifier, just because it is using GaN doesn’t necessarily make it better. This was shown in a recent high end class D comparison were a GaN based amp came second despite being considerably more expensive than the “conventional” class D amp that came out on top. A close third was a class D amp that cost considerably less than the GaN based amp.

We have listened to a number of highly regarded class A/B designs and a particular class D design we use was far better.

You mentioned Soulution class A, we know somebody who has had the 7 series (£50k +) in his system and changed to the same class D amp that won the shootout mentioned and is very happy with the changeover.
georgehifi's avatar
georgehifi
10,312 posts
 
you really must go and listen
I do, but sorry toetap I also go with the views of these 10 top amp designers, before listening to a retail salesman as yourself.
https://forum.audiogon.com/posts/1785554
ahofer
225 posts
 
This conversation turns a lot of my Audiogon impressions on their head. People who, I think, believe that great sound qualities can’t be measured are at the same time suggesting that because of inherent measurable design challenges of class D, that no class D amp can sound good. It also seems that more measurement-oriented folks may be coming out against class D because...I don’t know. The latest designs (NCore and purifi) seem to have dampened the IM distortion well into inaudible range. 

Nothing to do but listen to the new designs as they come out and try to get rid of our preconceptions. I have a cheap NCore design on order and I’m looking forward to possibly hearing the difference. Given that it is, effectively, a weak AM transmitter, I’m going to move it away from my sources, as that *could* be a source of problems. 
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