As with many of this year’s models, the NR1605 includes the latest Marantz smart ECO mode. This reduces power consumption significantly when the receiver is just used for background listening or running on lower levels without any negative impact to the audio quality. If the higher power is required while watching a movie or listening louder to favorite music, the NR1605 automatically switches to “full power output”. The smart ECO mode has three settings: Auto, On and Off leaving it up to the user to decide.
So here’s the response of D&M via email to me on how this works:
Response By Email (NJ Customer Service & Support) (10/11/2016 12:08 PM)
Hi Michael,
When ECO Mode is used, voltage for the amp stage decreases about 1/3 and amplifier stage energy loss decreases about 1/6 compared to ECO Mode being OFF.
It is recommend when using external amplification to leave ECO Mode set to ON. This will reduce power consumption to less than 70W.
When using ECO Mode ON at lower volume levels (under 45 Absolute) power consumption is about 1/2 as compared to leaving ECO Mode OFF. This is useful if using the AVR at night and you do not want to disturb others.
When using ECO Mode Auto, the circuit will control the power supply voltage by a relay. If the volume level is more than 45 Absolute the circuit will cut off. If the volume is less than 45 Absolute the circuit will switch on automatically. If listening at the threshold level (45) you will hear the relay clicking on and off frequently. Voltage for the amp stage does not change here, so power consumption would be the same as normal.
Thank You,
D+M Custom Install