I run mine headless and no problems rebooting it headless and managing it using Screen Sharing. I have nothing plugged into the display port.
I set it up to auto login to the main account with admin access. I use the Roon server which has no user interface and set it to launch at startup. I also set HQPlayer to startup automatically.
Here are Energy Saver settings:
Also, I issue this terminal command:
sudo pmset -a disksleep 1410065408
It keeps the disks from sleeping…even the SSD I assume.
Going back to try this cracked the nut, thanks so much! I had tried to do exactly that but Preferences wouldn’t let me. I just remembered to option-click the disabled choice and it told me that the Mac had Filevault on that prevents auto-login, which it’s the default at setup time. When I turned Filevault off I was able to change the to automatic login, and all is working now 
How many people are still arguing in the forums about this when the answer is so simple, although really hidden as the interactions between the different Preference choices are totally opaque…
You are very welcome!!
My M1 mac mini has been easier to manage than my sonicTransporter i9…
It is indeed.
No, it is not…
Thinking back, it dawned on me, the dummy adapter is needed on some machines running headless to allow an app to access intel H.265/HEVC hardware encoding and decoding. Which might apply to a Plex server but not a roon server.
So @musicjunkie917 is correct, it’s not needed for Mac Remote Desktop. 
I need more coffee 
Old MacMini (not M1) did, don’t know if it’s the same with MacMini M1
After the convoluted trip I described, my M1 is serving HQPlayer flawlessly from its closet location where it has no HDMI or any other connection except for Ethernet.
Back to HQPlayer on M1… I did my initial tests with 1x: poly-sinc-gauss-long, ASDMECv2, non-adaptive 48k*256 output. All good, just over 50% processor load. But I started noticing a lack of sparkle relative to the other system I have at my other place and I then realized there I use poly-sync-gauss-xla. When I selected that, I started to get dropouts, and processor load was way above 80%, which may be the reason. At the other place, I have an i9-11900 server with Embedded that stays at 50-70% load with that HQPlayer configuration. Decided to switch to adaptive output rate, processor load down to just over 60%, no dropouts, sounds like what I wanted. This seems all reasonable, just posting it in case I’m doing something wrong.
My M1 Mac mini is pure headless setup (no monitor, no keyboard and no mouse) and managed thru ARD. Works like an appliance. No HDMI dummy is needed.
Thanks, that’s what I have now for the Spring 2 except “ip” rather than “lp” for Nx. Working fine once I ticked the “adaptive output rate” box. For the May at my other place, I have fixed output rate, but a different server as I wrote above.
You want adaptive on the other server as well. It allows the server play tracks at both 44.1k DSD and 48k DSD as required instead of everything at the rate you select in the “Bit Rate (/ Limit)” drop down.
Just remember that most DACs don’t support DSD at multiples of 48k. Holo Spring 1 and Cyan didn’t support it either. But since Spring 2 it has been supported, including May.
You get lower CPU load by using adaptive rate, but there’s no quality loss by sticking to fixed 44.1k base either. So the only difference is in CPU load and RAM consumption.
Of course. But we are talking about two DACs that do support 48k…
To close this thread for now: thank you again to @musicjunkie917, @dabassgoesboomboom, and @jussi_laako for steering me through getting and configuring my Mac Mini > NAA > Spring 2 KTE setup. I’ve always liked the Spring 2, but I really did not know how good it could get until now via DSD256 with the right filters and modulator. Not quite the May I have at my other location with a similar configuration, lacking slightly in crispness of leading edges and micro-detail, but honestly I wouldn’t know if I did not have the May.
What comes after the Spring and May in each system ?
If you don’t mind sharing.
I’m moving stuff around a bit between the two locations, but here’s the main equipment:
I use the tube amps for more focused listening, as they need 15-30 minutes of warming up for best results, and tubes don’t last forever. I use the 3Fs for everyday listening, for instance while working. If I need to block outside noise, Verité closed, otherwise open, Atrium, or Auteur.
