Many amps change their frequency response based upon load. This was much more of an issue 30 years ago when it was discussed at length in International Audio Review. At that time many amps were optimized for an 8 ohms resistive load and went to pieces into other loads.
I believe that the extent of mechanical and electrical isolation issues presnt in a system is at least as significant as frequency response deviations and can help account for diverging opinions on Class D amps. I have found that my H20 and eAR amps benefit greatly from a good isolation platform (pneumatic or bearing design)and from electrical isolation from the rest of the system. Isolate a class D amp as you would your front-end. In my system this is accomplished by the use of FIM bearing-based isolation platforms, PowerWraps on the power cords and the isolated outlet banks of the PS Audio Premier. RF picked up by speaker cables can end up at the inputs of amps. Powerwraps seem to have a different effect than other RF treatments (ferrite rings, 'magic dust', carbon) by removing only the crud and leaving the highs alone. I notice that Dave Magnan has quite a list of tweaks for Nuforce amps over at his web site. Many of these address vibration and electrical issues.
Bob
I believe that the extent of mechanical and electrical isolation issues presnt in a system is at least as significant as frequency response deviations and can help account for diverging opinions on Class D amps. I have found that my H20 and eAR amps benefit greatly from a good isolation platform (pneumatic or bearing design)and from electrical isolation from the rest of the system. Isolate a class D amp as you would your front-end. In my system this is accomplished by the use of FIM bearing-based isolation platforms, PowerWraps on the power cords and the isolated outlet banks of the PS Audio Premier. RF picked up by speaker cables can end up at the inputs of amps. Powerwraps seem to have a different effect than other RF treatments (ferrite rings, 'magic dust', carbon) by removing only the crud and leaving the highs alone. I notice that Dave Magnan has quite a list of tweaks for Nuforce amps over at his web site. Many of these address vibration and electrical issues.
Bob