[Markvdv]

I had toroid inductors I changed to same I think you have now. Changed psu caps too, changed some other caps too,  removed some parts, changed 3v powersupply for a chip, added some decoupling in some places. Soundcheck has a blog that discribes more or less what problem areas were. What remained was layout that wasn't compact enough I think, UD80/20 looks better. I still like the 320, but weak points remain bass if you compare with other like tpa3116. High freq are a bit warm maybe too pleasant (gross exaggerated like all small differences). Driving lowish impedances (4 with areas close to 3) weakens bass/treble  further, heatsink gets hot then and amp basicly has hard time, max output then very low. I have some small Tangbands like that under my LCD televisionset  that lose a lot of music information then and max output to give you a comparison is lower then with PE sure3110! So important to pick speakers with nominal 6 or 8 ohm I think.

BTW powersupply made good difference, I ended with too big lol 500w smps connex.

[JohnR]

Oh, I suppose the DDX320 is a better answer to the OP's question, although currently out of stock - http://hifimediy.com/index.php?route=product/product&product_id=64

[JohnR]

Soundcheck has a blog that discribes more or less what problem areas were.

Looks like this is it - http://soundcheck-audio.blogspot.com.au/2012/08/ever-heard-about-full-digital-amps.html

Not much room in the UD80 box, you'd have to take it out to mod it I guess.

[Markvdv]

inductors look fine on UD20, I think also see some decoupling earlier 320's lacked, layout seems better, maybe latest version of 320 too, looks different

sinewave has also some digital amps I believe based on TI chips, but better ask about expected deliverytime befor buying lol read they had some big orders for other equip, not producing all amps all the time anymore. they have a sample shop on alieexpress