I recently bought Denon AVR 5803 and am planning to use it with external power amplifiers. The external amps (ADCOM GFA-565) will be connected to the pre-out jacks and I will only use the external amps to power 3 front channels. 1. Do I have to somehow "disable" the internal power amps for these channels? Will operating the internal amps with no speakers connected have any detrimental effects? 2. There are two "trigger out " DC jacks on the back of Denon AVR 5803. One is marked 12 V 20ma, another one does not have any marking regarding voltage and current. What is the output voltage of this second jack and what is the max current it can sustain? 3. I will be using with my power amplifiers the switched power receptacles in my power conditioning strip. These receptacles can be triggered with 10 - 30 V 30ma DC signal. Can I use the 12 V 20ma trigger outpoint of my receiver to control it? Thanks.