I went from Class D to Luxman A/AB - And most of what you think is wrong

@georgehifi  
Who said production boards will be soldered by hand?  Many small companies, including one I worked for, make small quantity of very sophisticated high density boards using Assembly Houses.  We used to make them with semi-automatic stencil printer, manual pick and place and 4 zone Heller reflow oven, but using Assembly house  ended up being much cheaper and better, quality wise.  Nobody sane would hand solder production quantities - too much time consuming equals too expensive.  We made batch of about 5 boards for prototyping and then about 100-200 boards in production quantity.  Using good Assembly House opens whole new world for designer (removes constrains).  Now he can design for higher density or even for BGA chips.  

Who said production boards will be soldered by hand?I didn't

I didn't, I inferred if you design a GaN board from scratch, you'd do the whole thing SMD because the GaN semiconductors are all SMD, therefore my statement was.
" They're not stupid and know it's impossible to create a "retail product" complete Class-D board, using all smd components, and making it by hand soldering"

@kijanki Thanks for your elucidation of some of what's involved with surface mount. I think a lot of people think that since we make tube gear by hand that somehow that means we don't have an education or something- or don't keep up with the times. We're using 603 components right now- as you point out, easy to do by hand. And probably too for production- depending entirely on volume of sales! On this basis, this statement:

it's impossible to create a "retail product" complete Class-D board, using all smd components, making it by hand soldering.
You say it can be done, but that would only be a 1 off prototype and not the production version.

-is simply false. Now at some point we may go to 402s just to reduce inductances and resulting ringing and radiation. But for now the 603s have worked out alright. If 'sales' translates to 100s of shipments, then its likely we will farm out the work.

it's impossible to create a "retail product" complete Class-D board, using all smd components, and making it by hand soldering

There appears to be a sleight of hand going on here, compare the above quote above to this one that appeared earlier:

To do that you need to buy either ready made boards then do simple mod and call them your own, if not and you want to do your own GaN Technology boards, you need the knowledge to design it from scratch, and you need some serious automated wave soldering machines to do all those smd parts that are involved, you can’t do it by hand. 

When comparing these two, we see that George had to back off from the idea that 'to do all those smd parts that are involved, you can’t do it by hand'; that's morphed into you just can't create a 'retail product' by hand soldering. Both statements are false. The soldering industry has all sorts of products designed for hand soldering work- and one of my employees worked doing production smd work all by hand.

Except for maybe a prototype, good luck hand soldering for retail production a Class-D that’s all SMD components like this cheap $34 Class-D stereo.

We're not planning to build a $34.00 amplifier and to be clear a $34.00 amp isn't going to have GaN FET output devices- such an amp would be all entirely on one chip. Its realistic to discount that comment as irrelevant.

Ralph + 1 burn: Fanning the flames

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).