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.


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.

Let me be clear, I like measurements. But a measurement is not inherently audible or valuable. An oscilloscope does not work 40 hours a week, and go home to listen to music. There's a big difference between a measurement and pleasure or desirability.

If there is 100kHz noise on an output, I'm not convinced it is audiuble unless I can hear it. If you go from 0.01 to 0.00001 distortion I'm not willing to pay 1000x as much for the latter.

People who cherry pick a measurement to make broad claims about the inferiority of one technology over another are not objective. They are just biased.
Quick interrupt! Here are some things you can’t measure. We have a lexicon of audiophile terms that most people understand. That’s how we communicate.

Soundstage height


By my estimate, the Icepower 1200as2 is around the $300 price per module. For the money, it's pretty good. Not so good for inefficient speakers though. All connectors on the 1200as2 are JST, using tin. I've had every single connector connected directly to the board (power/input/output), also using a high quality fuse. There was ZERO difference between direct/indirect connections. This is not a high current amplifier. My SS amp is much more dynamic and louder at a much lower volume setting. I'm afraid I agree with what Georgehifi has been trying to tell everyone (at least for lower priced class D).

Golfnutz you are drawing conclusions based on way insubstantial evidence.

There are in fact many high current Icepower based Class D amps out there and have been for years.

I own two: the BEL Canto ref1000m and the C5i. Look em’ up. I’ve used these with great results with various power and current hungry monitors and full range floor standers including Dynaudio, KEF, and OHM.

I also own a third newer (Fosi) that is a minimal design built around a TI Class D amp chip that only cost $85 and still sounds great with a pair of limited range small monitors (refoamed vintage Boston A40s...very nice). I don’t expect anything at that price to be able to drive a very difficult load but I suspect this one is also at least very efficient and probably can at least as well as most anything else anywhere near the price and certainly anywhere near its size (about the size of a pack of cigarettes).

Just spoke with ric via phone, looks like mine will not be ready to ship until late next week. I told him he should let people know what his time frame is. I think he’s been preoccupied but now ready to stay focused

Hard for me to imagine zero improvement when direct soldering and using high end fuse, but then a lot of people seemingly cannot hear when polarity is out, so...