I have a pair of Wharfedale Jade 5 floorstanders which were feed from Wiim Pro til Topping D30Pro to NAD C298 via XLR. The SPL was not satisfactory. Then I bought a NAD M22V2 with 2 x 300W (8 Ohm). Still the SPL was not satisfactory. From another room I had Wiim Pro Plus and this was connected to the M22 via RCA. Now the SPL was overwhelming!? Why? Can anybody explain!