TOPIC:

I'm not in a position to 'confirm' anything I'm afraid. You've presumably read through this whole thread which would be as much as I've seen too.

I have a Neo3 SHD and when I put it into standby before I go to bed I do hear what I think is the extra noise you refer to but I don't notice anything the following morning (in a quiet room). So I think the noise fades as you described, and in my case to a level that doesn't bother me. In term of the unit being warm when switched on I'm not sure what's troubling you? Yes mine gets warm as you describe but this feels totally to be expected to me. I do put my SHD in standby when not in use though, to not  waste electricity. Going to standby saves about 13 W of power consumption for me.

If you have concerns/questions about your particular unit note you can contact miniDSP support via the Support link at the top of the page. 

Thanks for the reply - much appreciated. I didn't mean to imply I was asking you personally to officially confirm anything; I was just relaying my understanding as a newcomer to the SHD who has been trying to gather information on this topic. I do very much appreciate your sharing of your experience with your unit - the coil whine, the fading of the sound over time, and the warmth of the top case being normal. I have contacted MiniDSP support as well.

Thanks again!

Yes, I was one of the early customers of the updated SHD devices and had an issue with the whining. 
Minidsp worked with me to fix the issue (I am an electronics engineer so this helped) and they released a new firmware version that removed the whining but increased the power in standby.
We worked out that the root cause was the transformer/PSU, so they sent me an updated module which I fitted and this worked.
No more whining and low power consumption in standby.
Outstanding customer service 👏 

Thanks so much for jumping back into this thread - much appreciated! I saw your posts over at the other forum too but forgot to tag you in my query there.

The aspect that has me puzzled here is that I only purchased my SHD about a month ago - I had assumed that MiniDSP would have ironed out this issue long ago, since it seems that folks were being sent replacement PSUs as far back as early 2021.

Also, my unit has the latest firmware, and I ran a manual update just to make sure - so it would appear that the higher idle/standby power draw is still not solving the issue with the PSU in my unit.

I would love it if MiniDSP could send me a new PSU as they've done for others in the past and that would eliminate the issue. I'm not an EE, but I can certainly swap that PSU given how simple the procedure is. (And while an amateur, I do know enough to be able to conclusively rule out DC in the AC line and a ground loop as issues here - this is clearly coil whine caused by some aspect of the PSU interacting with the voltage feed or whatever when the unit is put into standby.)

Alternatively - and I don't know if this is even possible - I would be content if the firmware could be updated to add a user option in the MiniDSP Device Console to make the remote control's power switch trigger a full shutdown (equivalent to flipping the rear power switch) instead of simply putting the unit into idle. Then any user with a hissing/buzzing PSU during standby could just select that option, which would enable one to turn the unit off from the remote and avoid the hissing/buzzing.

Finally, if you have any advice or recommendations about what specifically to tell MiniDSP support in order to get them comfortable with sending me a new PSU, I'd be grateful for your info (I have sent them a recording of the sound).

Thanks again!