2. amps-preamps
  3. 149476-20253

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 2 responses by ahofer

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. 
ahofer
225 posts
 
OK, I've had the March Audio p252 in the system for two days (Hypex nc252mp), so I'll follow up with my thoughts in this contentious Class D thread.

I had a bit of a long strange trip comparing it to my old amp (Adcom 5802). When I first connected the March, I was sure I could hear a difference. A bit tighter in the bass, not as smooth in the highs. Was the image not as wide? The soloists seemed a little further back? A difference in Cymbal decay?

This evening I had a chance to A/B them, albeit under less than ideal conditions. Since I had to power them off before reconnecting, there was a bit of a lag between listens, and, of course, I'm getting up from the couch to do it. Just to complicate things, the March reverses the channels, so I had to be careful to connect right channel on my DAC to left channel on the March. I put in a pair of speaker cables with bananas instead of spades, to make it easier. After trying to volume equalize on the music, I started doing it on a 1k test tone (with a decibel meter). As it happens, the two amps have the same gain, so I realized I didn't have to change the volume at all. Eventually I got the switch down to less than 30 seconds.

The better I got at making the swap, the less I could hear a difference. When I started I was almost sure I could. Ninety minutes later I'm pretty sure I would fail a blind test between the two.

On the one hand, I am reasonably persuaded by the volume of tests that suggest well-designed and adequately powered amps will sound very similar. On the other hand, on very first blush I immediately started hearing some of the things detractors say about Class D. Hmm, which way do my biases run?

All in all, it was a weird experience.  But it's nice to have a cool amp here in the living room, so I can leave the A/C window unit off and hear the music. Also, with only the DAC/Streamer and the tiny p252, I could get rid of the audio rack and de-clutter....

Next I'm planning to test the Orchard Audio PecanPi DAC/streamer against my current rig (Cambridge Edge NQ).

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