What is your favorite Class D amp?

https://doukaudio.com/products/douk-audio-ns-13g-max-hifi-mini-2-channel-stereo-audio-amplifier-class-d-power-amp-with-phono-300w-2

@devinplombier Take a look at the link above.

Only the 5 Watt power distortion is shown. 

The supply is rated 48V @5A. Look at the 4 Ohm power rated with this supply. Its 240V, the same rating as the output of the supply! By that metric the amplifier is 100% efficient. Since that isn't so, its pretty obvious that things aren't going to measure up as claimed. 

What you don't see is the 10A supply for this amp. The stock supply is a 5A unit. As long as you don't push the amp hard it will not make much distortion. Funny thing, the amp uses a chip and isn't GaNFET, but the power supply is marked 'GaNFET Adapter'.

I'd be curious to see how this amp holds up running at full power with the 10A supply. 

IME if you want to make a class D amplifier do its thing, the power supply is vitally important. What we don't know here is what supply was being used when the amp was tested, what load impedance it was driving and so on. 

If the supply has trouble holding up at power (which I have to assume is the case, given the output power figures aren't correct), the distortion will rise. 

But as I said when this first came up, amps like this challenge stuff costing a lot more. I'd be interested in seeing what it does with a proper power supply. 

@atmasphere wrote:

The supply is rated 48V @5A. Look at the 4 Ohm power rated with this supply. It’s 240W, the same rating as the output of the supply! By that metric the amplifier is 100% efficient. Since that isn’t so, its pretty obvious that things aren’t going to measure up as claimed. 

[...] I’d be curious to see how this amp holds up running at full power with the 10A supply. 

Well, according to Douk’s product page, with the 10A power supply the amp makes 250w + 250w @ 4 ohm.

In other words, it takes in 480W but outputs 500W. Magic! 😃

This brings up a great point, namely that manufacturers’ power claims and ratings should be taken with a grain of salt until they’re carefully looked into. You’d expect these kinds of shenanigans from Douk or other entry-level brands out of China, but wannabe high-end manufacturers like NAD play even worse games.

For instance, Bob Carver makes (made?) a very nice-looking tube amp rated 75wpc, but its output transformers were so small there was just no way, and sure enough ASR measured it clipping at something like 17 watts.

You’d think ASR would have reviewed the Douk but sadly they haven’t. That might have shed some light on its real power and THD+N numbers.

But as I said when this first came up, amps like this challenge stuff costing a lot more.

That’s for sure! Though as you’ve stated PSU quality is key, and in that price range a good PSU can easily cost more than the amp it powers.

@devinplombier Yes, it seems we're on the same page :)

Carver also made one called the cube. Supposed to be 400W  of power 200wpc. It was small, and light weight, maybe 6 or 8 inches square and had more like 40Watts, if that. A friend of mine bought one and brought it over to demo on my system. It was pathetic. 

devinplombier, the TDA3255 is no where near the 250 watt rating per module  Input is 240 watts per pair. Efficiency is 80%. Output is 192 watts or 96 watts per module. However 80% efficiency may be doubtful. I say each module provides 65 watts RMS per channel and I use about 5 watts average for listening. No matter what some others stated distortion is about 1% at the 65 watts per channel.

The Douk NS-13G will sound as good as expensive amps till your speakers exceed at least $2K. Then you may hear some improvement with the expensive amps and speakers, Unlike the Douk some amps do not have tone controls to tune your speakers response.