According to this site they use the ASX-2 modules. I wonder what configuration of those gives 220/400 watts into 8/4 ohms.
http://www.computeraudiophile.com/f6-dac-digital-analog-conversion/peachtree-grand-integrated-10630/
http://www.computeraudiophile.com/f6-dac-digital-analog-conversion/peachtree-grand-integrated-10630/