Which powersupply goes with the new Hifimediy DDX320v2 2.1 Digital Amplifier.
I live in Denmark (230 volt)
about 6 years ago
You can roughly calculate 80% efficiency. So if your stereo speaker are 6 ohm and the sub is 4ohm, they could draw up to 360W/0.8 = 450W. SMPS300R outputs 300W constant and 400W peak which will be enough in many situations, but in the above situation a 500W PSU would be better if you plan to play at max output.
If all your speakers are 8ohm they can output up to 2 x 75w + 1 x 80W = 230W * 80% efficiency = 287.5W. In this case smps300r will be more than enough.
SMPS 28V version should be adjusted to its max around 30V, and 38V needs to be adjusted down to min (35V). Note that if your stereo speakers are 4 ohm, then 30V is max accepted for DDX V2 amp.