AVM is not class D. Its Class A/AB as far as i know. I have some experience with the Evolution Range. Currently running AVM M30 Monoblocks into Dynaudio Sapphire. It will play in the same league as a NAD M22, Bryston 4B, Rotel RB 1590, to name some better known competitors. The sound signature is: transparent, detailed, not cold but nicely analytical. I had also the Preamp of the evolution series. I did not like it as, for my taste too analytical, thin sounding.
I have a Benchmark DAC3 HGC which serves as preamp also. It is detailes, musical, transparent, fullbodied, It complements the AVM M30 nicely.
There is the more expensive Ovation series that plays in an other leage. Some of the models have tube sections, probably sounding slightly different again.
But yes in Germany, their origin, they have the image of being analytical and transparent.
Hope this helps a bit.