The Topping TP60 amp is quite decent. Certainly for the money it costs and it deserves better than to have one channel driving a sub and main speakers. You'd probably blow it up doing that anyway, the load is likely to be very low impedance. Mind you, I hate subs anyway. I've never heard a system with one in where the sub was not affecting the sound in a way I didn't like.
Get the Topping and use it just as the main amp only. It's punchy and clean sounding, with a slightly reserved quality (some might say dull), but It's pleasant.
It is impossible for anything digital to sound analogue, because it isn't analogue!