Interesting Receiver behavior. Can anyone explain?

So I have a Onkyo TX-NR686 connected to my Kasa HS-300 as part of my entertainment system and have noticed an interesting behavior. (It sits on it’s own Kasa outlet, so the detection is not a problem).

First the observation:
Whenever I turn it on, it consumes ~55W for exactly 30minutes, then drops to ~38W for the rest of the session. There is no change in volume, input selection, or anything else. Input is a “chromecast with Google TV” dongle connected to one of the HDMI ports and HDMI out is connected to the 4k TV.

Here is the chart for two successive nights, but it is always the same!:

I wonder if anyone can explain this behavior. I am sure there is a reason. Why does it work 17W harder for exactly the first 30 minutes after coming out of standby? (If I turn the receiver to standby and on again, there will be another 30 minutes of 55W). Obviously it is programmed to behave this way, but why??

Note that the specs give a power consumption of 580W (I guess with both zone at max volume!) and a “no-sound” power consumption of 60W. I am nicely below that. :smiley:

(Sorry, not sure where this post belongs (Stories? Detection? Technical?). Feel free to move it to another area)

@altenbach Also very curious about this, as i’ve noticed similar “oddities” with some receivers that have been submitted to the device library/to the forums. I did go to the product specifications page on B&H to see if anything there gives me an indication, and didn’t see something obvious, other than a “Hybrid Standby Function”

Anyone very familiar with receivers / our resident electrical engineers are welcome to share their more knowledgable take on what could be going on here!

Quite jealous of your receiver. Being a Bluetooth, Wi-Fi, Ethernet receiver I would imagine it is related, going to sleep after looking for updates, new devices, etc…

Hybrid standby is <<1W and is sufficient to wake it up via HDMI CEC. Enabling network standby raises that to about 2-3W and I have that turned off. I also have Bluetooth off. HDMI “standby through” is expensive (~6W!) and also disabled.
The manual page 133 is actually very detailed about the cost of enabling these functions:


I will watch it more closely, but I remember hearing a faint click during use, like a small relay. There is no change in sound or surround mode when that occurs. Maybe that’s what happening after 30 minutes to take certain parts offline (e.g. the amplifier for the second zone which I don’t even use). I will try to correlate the click with the elapsed ON time next time I hear it.

My curiosity is raised. Stay tuned…

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It should not take 30minutes to look for updates (I am on 500/500 fiber) and it should not take 50% more power to do so.

I bought it for < half price right after the new model (TX-NR696) came out so it was a deal I could not resist. ( My old Pioneer was still good, but did not support 4k.).

While the amplifier specs are identical, the new model eliminated the composite and component video inputs. (and has a more confusing remote with more buttons). Despite that, the new model consumes more power, at least on paper. (+5W for No sound (65W vs 60W) and +55W for max (635W vs 580W)). No way for me to test.

Two thoughts.

  • a good place to post would be the Community Device Library
  • You can see my sort of similar Yamaha receiver behavior there.

Wow, very detailed and well written manual! You certainly don’t see that much nowadays.
Could well be amp for zone 2 but with so many features it’s really hard to guess. Could be some combination of features. Have you tried playing around with the auto standby features, turn everything on/off and wait 30min, see if anything changes? What about AccuEQ?
Will be interesting to see what you discover.