cycling DAC power reboots Mac Mini music server

[rustyshackleford]

I am using a "headless" mid-2010 Mac Mini (running El Capitan) as my music server, using iTunes with 44.1khz rips of CDs.  Connecting an XDA-2 via USB.

I'm having a peculiar problem.   When I cycle the XDA-2 in&out of "standby", the Mini reboots.   I don't believe the XDA-2 is the culprit, because if I connect it to other Macs, I don't see the problem; also, it looks like other people have seen similar problems with Minis and other DACs..    I've tried a USB isolator on the USB cable, and I've reset the Mini's SMC and NVRAM.    Has anyone else seen this kind of behavior ?   Any suggestions ?

Maybe I should just use the TOSlink output from the Mini.  I guess this is a whole 'nother discussion, but some people say the USB is better because it has less jitter.   Of curse, the XDA-2 has the ASRC to handle the jitter.   But I believe it re-samples to 96KHz, which might not be the best thing since I'm mostly playing 44.1Khz rips.

Thanks.

[Loop 7]

I use a headless Mac Mini as well.

What's the music server or playback software on the Mac?

Do you have another DAC you can test with?

Have you created another user account and tried to reproduce the issue?

[rustyshackleford]

Using iTunes, mostly to play CD rips (44.1khz/2x16bits).

No I don't have another DAC.  But like I said, the XDA-2 causes no problem if I hook it up to my Macbook.  Still, it would be an interesting experiment.  I guess could buy a cheap little one to test with.   

I hadn't tried another user account (never set one up yet).   But you got me thinking.   So I logged out, and the problem went away (cycled to standby and back to active, with no crash of the Mini).   Then I set SystemPrefs->Sound to something else (besides USB) and again problem was gone.   But this behavior isn't reproducible - I tried cycling standby again when logged out, and it rebooted, and this happened more than once.     Given problem is sometimes better, but not completely gone, when logged out (and of course iTunes isn't running) I doubt it's user account or iTunes specific.

Given the USB isolator didn't help, that suggests it's not some kind of hardware noise glitch.    OTOH, it's dependent on whether or not there's a USB cable connecting the XDA-2 to the Mini, and occurs even if the XDA-2 is not set to the USB input and SystemPrefs is not set to the USB output.  I guess I could try putting a USB hub between the Mini and the XDA-2.
 

[creimes]

Simple suggestion is what you already mentioned just change to Toslink, I've never noticed any sound difference on any of the different inputs especially CD.

Chad

[AudioHTIT]

I have a 2012 Mini attached to a DC-1 via USB, also using iTunes; I turn the DC-1 and off regularly and have never noticed this issue. I’m on High Sierra (10.13.4) though I had no problem with El Capitan either. You say others have had this problem, where did you see that? Have you tried the Apple forum? Of course the TOSlink workaround might solve the problem, but USB should work. The Hub is an idea for troubleshooting, but I probably wouldn’t want it in the path normally. Sorry I don’t have more.

[DYohn]

Many if not most USB DACs use the 5V power from the source (your computer) to power the receiver portion of their USB input. I do not know if the Emotiva DAC does this, but I would not be surprised. My suggestion is to either leave the DAC on all the time (not a bad idea in any case) or install a USB hub (or some other USB device that provides a separate power supply) between the computer and the DAC.

[leonski]

I would go to the MacMini Preferences pane. Click on the 'Apple' in the upper left corner and look thru power save / recovery options.
The Confuser MIGHT interpret the momentary interruption of the 5v power (thru USB) as some kind of power interruption event.

I'd FIRST look in the 'Power Saver' pane and unclick restart after power interruption and check out the other options.

Please report back if that works.

[Gary Cook]

I have a current generation MacMini with a BigEgo DAC which is powered by the MacMini via the BigEgo's USB cable. Never had an issue with it or any of the other USB DAC's that I had before it. As leonski suggested I'd check the power save set up.

Cheers
Gary

[leonski]

(Fingers crossed. Can I get lucky?) *

[rustyshackleford]

May 20, 2018 10:01:48 GMT -5 AudioHTIT said:

Lot to chew on here, folks, thanks. Responding to various questions & ideas ...

Saw that others have had this problem by looking around the Apple forum,  searching for stuff like "USB causes reboot", and people are having weird problems.   But nothing all that similar to my problem, and no responses yet to my specific inquiry (hopefully something when work week starts).

TOSlink definitely solves problem, but I feel like USB ought to work, and it sounds like people think it's better sonically.   Like I said, my understanding is that's because of jitter, which ASRC solves, except I believe it resamples to 96khz, which given I'm playing 44.1khz CD rips, could cause artifacts.

Leaving the DAC on all the time solves it too.  I 'm not sure how much power it draws when inactive but not in standby.  Maybe not much, but I'd really hate to do that as Emotiva just finished dealing with the problem of having to cycle the thing in&out of standby a couple times to get sound.   Woulda saved them (and me) a lot of trouble if I knew I'd end up just leaving it on all the time anyhow :-(

If the USB hub solves the problem, that'll certainly be interesting (and probably instructive).   Can anyone surmise how it might affect the digital stream ?

I went to SystemPrefs->EnergySaver and unchecked "start up automatically after a power failure", and the problem still occurs.  Seems really weird - seems like with that unchecked, it should just crash, and not reboot.   I didn't see any other settings that seem relevant.

[leonski]

HMMMMM. Unchecked 'start auto after PF' and it still recurs.

Just for curiosity, you might want to buy or borrow a 'Kill-A-Watt' meter (maybe 25$) and check the idle power draw of your DAC.

Toslink has the advatage of NO electrical connection. This 100% eliminates ANY possibility of ground loop or 'hum' related issues.

*Go to 'finder' 'Utilities' than 'System Information App' and look @ USB. When the event happens you might see something on one of the USB channels?

Call APPLE and find out from a PRO if one of the functions (Really Extensive!) will help you diagnose the problem.......System keeps 'logs' of everything, too, so try to find
someone to help you dig thru THAT.

I'm NO PRO at this but I'm as tenacious as a toothache.



MY DAC, a CambridgeAudio DACMagic Plus is connected with USB from a 2009 iMac to the DAC.   NO problems or issues noted.   And it sounds fine, even using the 'remote' application loaded to my phone!
I'm running the most 'recent' OS the thing will take, maybe 10.11 or so.....nothing more recent will work.   

[DYohn]

Try a USB hub - or if you are worried about sound quality degradation, something like a Schiit Wyrd.

[rustyshackleford]

May 21, 2018 12:00:34 GMT -5 DYohn said:

Try a USB hub - or if you are worried about sound quality degradation, something like a Schiit Wyrd.

Wow, reading all that talk about noise on USB makes me think optical is the better approach.

[DYohn]

May 21, 2018 12:30:37 GMT -5 rustyshackleford said:

May 21, 2018 12:00:34 GMT -5 DYohn said:

Try a USB hub - or if you are worried about sound quality degradation, something like a Schiit Wyrd.

Wow, reading all that talk about noise on USB makes me think optical is the better approach.

Optical and USB are likely pretty darn close. Coax S/Pdif is much better than either of those, but it's not an option you have with a Mac. Try a hub or one of the USB cleaner devices first is my advice. You can pick up a USB hub really inexpensively to see if it solves your problem.

Or, like I said initially, just leave the DAC on all the time.

[KeithL]

I've never seen that exact situation before... but I have an idea...
Unfortunately I suspect it's something in how the Mac is configured.

When you connect a USB device to a computer, the computer can detect, separately, when the device is physically connected, and when it's on or off.
So, when you connect a DAC to a computer, the computer "feels" that it's connected, even if it's off.
There is then a separate signal involved that tells the computer when the connected device is on.
What the computer DOES when it senses these situations depends on internal settings - which may or may not be accessible.

We have heard of a somewhat different USB issue that's quite common with Mac Minis.
What many people have experienced is that, when the Mac hibernates, it fails to see the DAC when it wakes up from hibernation.
When the computer wakes up it's supposed to "scan all its USB ports to see what's connected".
However, for whatever reason, either it doesn't do so, or it does so, but fails to update the list of audio devices.
And, when this happens, turning the DAC off and on again triggers the computer to re-check the attached devices, and it again sees the DAC.
(In a sense the computer is being triggered to repeat part of its reboot routine.)

In short, it would seem that your particular Mac Mini has gotten itself configured to completely reboot when it detects that the XDA-2 is connected and on.
We know that the computer can detect when the DAC is connected, and we know that it can decide to reboot itself.... but it has "become programmed" to reboot WHEN the DAC is connected.
(This can happen for a variety of reasons if the computer "decides it needs to reboot to fix something".)

At a guess...
We know the Mac has built in drivers for UAC2 DACs like the XDA-2.
Perhaps, when it detects the XDA-2, it tries to load the drivers, fails, thinks they're missing or corrupted, and is rebooting to try to fix the problem.
This could happen if the drivers are in the wrong place, or if some other audio program has messed with the configuration, or if some internal setting has just gotten corrupted.

Another guess might be...
Every USB host device has internal settings for the maximum amount of current it is willing to supply to USB devices connected to it.
When you connect each device, it tells the computer how much current it requires, and the computer has the option of refusing to connect to it.
Normally the most this will do is to cause the USB device not to work (this sometimes happens with USB-powered DACs and phones).
The XDA-2 actually uses very little USB power - so nothing should have a problem with it.
However, if some setting in the computer has gotten corrupted, it could be "mis-reading" that, or some other piece of information passed during that negotiation.
And, again, the computer may then trigger a reboot to fix a real or imagined discrepancy.
There could also be a hardware or software malfunction in the computer's USB port itself which reports a fault and triggers the reboot.

The problem is that computers have a tendency to "reboot to protect themselves" when they sense any of a large number of "problems".

Unfortunately, this would probably be some sort of configuration setting in Apple's equivalent of the registry (which is just a massive database of settings).
Those settings can be altered by programs when you install them, deliberately or accidentally, or can simply become corrupted, and tracking down a problem can be difficult to impossible.
On Windows computers there are actually utility programs intended to look for and fix "obvious errors" - but, to be honest, they tend not to work very well.
(These sorts of problems often end up being a "reinstall the operating system and hope it goes away" sort of problem.)

I would suggest Googling on the problem....
Both in the form us "Mac Mini reboots when I turn on my DAC..."
And the form of "Mac Mini reboots when I connect or turn on ANY USB device" (the problem may occur with various devices)

You may also find that it acts differently depending on what other USB devices are connected... or which USB port the XDA-1 is connected to.

May 19, 2018 17:41:13 GMT -5 rustyshackleford said:

I am using a "headless" mid-2010 Mac Mini (running El Capitan) as my music server, using iTunes with 44.1khz rips of CDs.  Connecting an XDA-2 via USB.

I'm having a peculiar problem.   When I cycle the XDA-2 in&out of "standby", the Mini reboots.   I don't believe the XDA-2 is the culprit, because if I connect it to other Macs, I don't see the problem; also, it looks like other people have seen similar problems with Minis and other DACs..    I've tried a USB isolator on the USB cable, and I've reset the Mini's SMC and NVRAM.    Has anyone else seen this kind of behavior ?   Any suggestions ?

Maybe I should just use the TOSlink output from the Mini.  I guess this is a whole 'nother discussion, but some people say the USB is better because it has less jitter.   Of curse, the XDA-2 has the ASRC to handle the jitter.   But I believe it re-samples to 96KHz, which might not be the best thing since I'm mostly playing 44.1Khz rips.

Thanks.

[leonski]

MANY of the suggestions Keith makes will be part of a LOG which the computer keeps.

Check the Utilities in 'finder' / 'applications' and look around.

I don't know where the logs are stored, offhand, but they are there. You might have to 'enable' logging and induce the fault to see what it's doing.
Than it might be fixable using 'console' but be careful there.

[rustyshackleford]

May 22, 2018 12:45:16 GMT -5 leonski said:

MANY of the suggestions Keith makes will be part of a LOG which the computer keeps.

Check the Utilities in 'finder' / 'applications' and look around.

I don't know where the logs are stored, offhand, but they are there. You might have to 'enable' logging and induce the fault to see what it's doing.
Than it might be fixable using 'console' but be careful there.

'Console' looks like the only relevant Utilities app.     And it does show extensive logs, but I can't make much sense of them; nothing really stands out, except maybe some references to 'com.apple.sandbox.system-policy-violation' which seem to occur around the time of the reboots.

Keith's list of possible reasons (thanks for the extensive post, Keith) is daunting, and I think down that road leads madness (for me, at least).  I guess I'll try a USB hub, but Keith's belief that's not the XDA-2 drawing too much USB power suggests it won't help.   And whenever I've seen that, the Mac (not this one) simply gives a message saying it can't handle the device.   I've tried most if not all of the Mini's USB ports, with no difference.

I've tried the Apple forums, and no responses whatsoever.   When I google the problem, I end up with stuff about kernel panics, which I don't think it is because I don't get the "your computer restarted because of a problem" message.

I think I'll either go with the Mini's optical output.  Or leave the XDA-2 on all the time (once I've checked its quiescent power), which if I end up going that way, will be sadly ironic (to me and Keith, at least :-) ).

[leonski]

It is POSSIBLE that were to you copy the part of the log which catches your eye and Post it to either Apple or one of the 'AppleCare' type DIY sites, that someone would give you some insight.

The system monitor app MIGHT show a glitch, too, which you can get at from the Utilities folder or maybe from the 'Apple' / 'about this mac' / system report / (***) You could look at USB or a few other choices which MIGHT help.
I see a 'diagnostics' click which might log any obvious problem upon reboot or the reason FOR the reboot.

You need a real 'under the hood' Apple Pro.

[rustyshackleford]

Duh, well I measured the power consumption of the XDA-2 when it's in "active mode" and it' 15watt/22VA (using a Kill-A-Watt meter). So I think   I'll just leave it in active mode all the time. Thanks for all the suggestions though.