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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
toetapaudio
474 posts
 
@georgehifi, that’s uncalled for, you have no idea who I am, my background and knowledge. 
georgehifi's avatar
georgehifi
10,312 posts
 
Armed with this knowledge it might be interesting to ask a manufacturer of a GaN-based class D amp why their amp is so much more expensive.
You’d have you been asleep, that goes with any new ground breaking technology eg:TV’s
The first models in audio by the boutique manufacturers are always sky high priced because they make their own boards, then once that new technology has proven itself to be the future, those pesky people in Asia like  get hold of it and design and manufacture complete boards in the millions for a $100 dollars, that’s when the smaller manufacturers get them and charge too much because they put them in glitzy chassis and charge a fortune and rest on their past names.

soundsrealaudio....."Hum class D....should I sell my 300B???"

This guy thinks so!!!

https://www.youtube.com/watch?v=VMc7Y1RYiwE
Yes expensive also but they are the new GaN Class-D technology, stuffed inside a stupid tube housing, to keep the tube guys happy.

Cheers George
mapman's avatar
mapman
22,117 posts
 
YEs TI appears to have GaN based Class D modules now and can’t imagine those cost much more than their others. Anyone know of amps that use these?

FWIW I have a ~40-50 w/ch Fosi Class D bluetooth integrated amp that uses a TI Class D module. It’s slightly larger than a pack of cigarettes and <$100 on Amazon. It is not GaN as best I can tell but the sound is quite impressive especially for that price. It replaced a classic NAD 3020 receiver. Sound is night and day different from the old NAD. Much more detailed and holographic, less warm, and less fatiguing to boot.
atmasphere's avatar
atmasphere
11,772 posts
 
Ralph, not meant to be insulting, but couldn't you sell your products for a lot less? Nothing there that's cutting edge, though I do understand that highest quality parts cost significantly more

And wouldn't the GaN input buffers need to be a lot more exotic= $$$?
All of our products are built by hand, and to that end set a pretty high bar in terms of construction quality. Despite that we are expecting our first class D entry to be less expensive than most of our amps are right now.
georgehifi's avatar
georgehifi
10,312 posts
 
mapman Yes TI appears to have GaN based Class D modules now and can’t imagine those cost much more than their others. Anyone know of amps that use these?

Thanks for that info.
Didn’t think it would be long before big companies like TI (Texas Instruments) got into GaN for audio use, others like Motorola ect will follow

Here is a snippet from TI’s propaganda on the GaN technology.
"GaN FETs provide superior switching characteristics, which enable even higher efficiency, better thermal sinking reduced size and weight, as well as reduced distortion for Class-D audio solutions.

GaN’s inherent characteristics provide a more ideal model of a small-signal PWM, driving the output filter. Along with this, the absence of a body diode eliminates reverse-recovery charge, which enables increased output linearity. Both characteristics allow GaN to minimize THD and ultimately create higher-quality sound."

Cheers George

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