From what my electrical engineering buddy has told me, you can judge the power output on your amplifier to a certain degree if you have a volume that reads in minus dB. At 0 dB you are providing 100% amplifier power and something like -3dB is half power. I have a few CDs that I can listen to at, or near, zero, but the majority are at a volume lower than -10dB.
Maybe someone else will correct me on this or provide more insight.
Also, the Denon is listed as 4 ohm (high current) capable, but I'm sure the Marantz is as well. The specs should indicate the rated speaker range of either 4 ohms to 16 ohms or possibly 6 ohms to 16 ohms. If it isn't rated for 4 ohms I think you'll like the Denon.
Maybe someone else will correct me on this or provide more insight.
Also, the Denon is listed as 4 ohm (high current) capable, but I'm sure the Marantz is as well. The specs should indicate the rated speaker range of either 4 ohms to 16 ohms or possibly 6 ohms to 16 ohms. If it isn't rated for 4 ohms I think you'll like the Denon.