Do Class D amplifiers sound a lot better than Class AB Amps?

[Howard]

I don't think you understand me. I am saying that you can build a Class D amp that produces negligible EMI/RFI at little extra cost (perhaps none; I am not a amp designer) versus a Class D amp that floods the vicinity with noise. What the amp actually gets sold for has little to do with that.

 

[Fallen Kell]

I don't think you understand me. I am saying that you can build a Class D amp that produces negligible EMI/RFI at little extra cost (perhaps none; I am not a amp designer) versus a Class D amp that floods the vicinity with noise. What the amp actually gets sold for has little to do with that.

Correct. The companies use it more as a way to have different tiers of product, allowing them to have something that has a 20-30% profit margin (or more) on the "high-end" product. The "low end" one is to get market penetration with only minimal profit. It is all about the money guys, just remember that.

 

[Modelworks]

I don't think you understand me. I am saying that you can build a Class D amp that produces negligible EMI/RFI at little extra cost (perhaps none; I am not a amp designer) versus a Class D amp that floods the vicinity with noise. What the amp actually gets sold for has little to do with that.

It actually doesn't cost any extra in parts , it does cost more in design time depending on the application. A lot of it is just in how the pcb traces are routed. A good design will make heavy use of ground planes and avoiding long straight traces that might work like an antenna to transmit the RF. I have a class D amp made by insignia (best buy cheap as they can find to make it brand), and setting it on my workbench , without the cover on it, and operating it, my scope doesn't pick up anything when the probes are near.

I can put a CFL bulb in a desk lamp and place it 4 feet from the scope and it causes all kinds of rf interference when running. Took me a few minutes to figure out what was going on when I switched to using a CFL in the lamp. I did it to reduce the heat output because I use the lamp to light up the work area. Had to go back to incandescent.

 

[HeXen]

well regardless, i'm sure we answered the OP's questions. But with Class D, i still say you really need to pay attention more so than Class A or A/B, to exactly what your buying. They are a more difficult design and therefor needs some buyer beware.
There are also a ton of marketing gimmicks to read into. Plus different manufactures use different methods, what to me seems to be the same outcome, like Class B/D, G/H or H or Class T. Or even the newer methods of using higher efficient Class A/B using single rail caps to boost the voltage and therefor power to enable smaller applications with large power outputs and still yields upwards of 75% +/- efficiency