I have a prologic receiver and i think its time to upgrade to a DD amp.. but that's where the strugle starts..i read different opinions about DENON and YAMAHA.. one of them is very interesting : "...Here is where the big difference comes. I think that this is a matter of sound philosophy employed by the two companies. What Denon does is: Bass correction +/- 10dB @100Hz, Treble correction +/- 10dB @ 10kHz. By increasing the bass and treble we are adding too much mid frequency gain to the overall sound picture, thus changing the original sound image too much. What Yamaha does is: Bass correction +/- 10dB @ 50Hz, Treble correction +/- 10dB @ 20kHz. Adding a 1 or 2 dB of bass or treble will only underline the two extremes of the sound picture, without changing the amplitude of the mid range spectrum at all. The human ear is very sensitive to the frequency range of 1kHz to 5kHz, so any change in the level of this frequency will increase the level of the presence you feel, but it becomes really unpleasant to listen to for a long time.. " so.. what do you say???