I have denon avr-x4400h and parasound a21+. So I connected fronts(kef r11) via pre out in avr and via parasound. But I still see denon avr-x4400h produce same amount of heat. It looks like even though I connected fronts via pre out and only play stereo music with stereo channel option, denon avr-x4400h still doesn't turn off internal power amp. Am I missing some settings in the avr-x4400h? I don't see option in avr-x4400h to say just use pre out for fronts in my 7.2 setup. Please help me
You can do it, but you have to first select the 11.1 layout and then select front to pre out.
Go to Speakers/Manual setup/Amp Assign and you should see the following:
After that you can reconfigure you speakers to 7.1 and your front left and right channels will remain assigned to Pre-out, that is, the internal amps (front left/right only) will remain disconnected.
Doing it this way, the pre out for the two front channels will be disconnected from the internal front left and right power amps only. The other 7 pre outs will still be connected the corresponding internal power amps.
Note: As others mentioned, the internal amps will still be powered, only their inputs are disconnected from the pre outs. That is exactly the same even for the newer models that can run in full preamp mode.
The main reason to do this is so that you can push the A21+ to its output limit, and the pre out THD+N will remain very low, much lower than the A21's own THD+N. That is good on paper but won't likely result in audibly better sound quality because the Denon's internal amp's are just as good as the A21+ if used well within its output limit.
If you want the AVR to run cooler, you have to turn ECO on, auto will only work if you listen with the volume set to below a certain point, something like below -30, otherwise ECO set to auto will be the same as ECO off.
Just to disconnect the two internal amp won't reduce the heat by much, in fact even if you have the X4700H that allows you to use preamp mode, it will still not run much cooler if not for the fact that in preamp mode it automatically turn ECO on. With ECO on, the rail voltage will be much lower, that's what makes the unit to run cooler.
