That's the great thing about Class D. They are the most efficient amplifier type. They barely consume any power when just sitting powered on, but idle ; Maybe just a watt or two. I believe NuPrime amps are something like 90%+ efficient. This means virtually all power drawn from the wall (while playing program material) is being used to power your speakers, and very little is wasted (ie turned to heat). So, if you checked the voltage on your Furman while the amp was just sitting there powered on idling, it wouldn't so much as register the tiniest blip.
From Wikipedia:
Theoretical power efficiency of class-D amplifiers is 100%. That is to say, all of the power supplied to it is delivered to the load, none is turned to heat. This is because an ideal switch in its on state would conduct all the current but have no voltage loss across it, hence no heat would be dissipated. And when it is off, it would have the full supply voltage across it but no leak current flowing through it, and again no heat would be dissipated. Real-world power MOSFETs are not ideal switches, but practical efficiencies well over 90% are common. By contrast, linear AB-class amplifiers are always operated with both current flowing through and voltage standing across the power devices. An ideal class-B amplifier has a theoretical maximum efficiency of 78%. Class A amplifiers (purely linear, with the devices always "on") have a theoretical maximum efficiency of 50% and some versions have efficiencies below 20%.
