Modi problems, good news, workaround without reboot.
Report: The Modi sounds great for a certain period of time.
I have tested the device from USB powered hubs, directly to
two different Macbooks and I definitely have an ISSUE.
Background:
I am far from a MacOSX expert but I am intimately familiar with
the workings of the CoreAudio Stack.
I worked the Modi through all my Aggregate Devices, Multi-Output Devices
and through several different routing configurations with Jack Audio, Audio Hijack
Soundflower and MAX/MSP.
The CoreAudio/Audio Midi Setup in OSX, lets you see where clock is derived from

In Aggregate and Multi Devices you can select a specific device. I present this
as there are many test cases and use cases that are absolutely regular and do
work with other USB audio devices. Definitely there can be more debugging
but if the MODI is a "USB audio class device" it should work.
Of note you can also do re-sampling and drift correction within an Aggregate or
Multi-Device Output, you can also have any number of these with any combination
of different audio devices even firewire.
Problem:
At any given moment in time it could and I have experienced a few failure scenarios.
1. Right channel is lost, replaced by background digital clipping
2. Left channel is lost, replaced by white noise
3. All audio stops, no sound, empty
4. A digital clipping starts at low volume then ramps slowly to MAX output (SCARY)
By far the weirdest is losing one channel. since the other channel is working.
I will highlight the more advanced use case just because it is also a great testing platform.
The simplest setup and anyone with a Macbook and a DAC and two amps (lol) can do this.
With the aforementioned Multi-Output device, you will create a new device and add the
Mac's Built-in Output and MODI together into a device.
Multi-Device Output (24bit 48khz) Clock Source (Built-In or Schiit doesn't matter)
->Built-In Output
->Speaker-Schiit USB Audio Device
Right click on Multi-Output and select "Use this device for sound output"
Fire up Itunes play a song, and it comes out both devices at the same time, simple.
Wait then at sometime even up to a day later only the MODI drops out
Another from my working setups.
For example, Modi 1 + USB audio (2/4out) + Built-in Output (24bit-48hz)
The Modi will stay accurate in reference to sample rate for some period of time, it
does seem arbitrary after about 30 minutes. Then a failure occurs. I like this use case
as well because another USB audio device with a different chipset is involved. Other
devices still output correctly. Modi is in one of failure states.
Diagnosis:
I say clock or USB chipset implementation of the MODI seems to be the culprit
because the only way to fix this is to change the sample rate in Audio Midi Settings
You must change the MODI to a DIFFERENT sample rate then change it back again.
Once it flips back and sometimes immediately on change to new sample rate the
MODI will again function.
Oddity:
I have also seen a very bizarre event whereby the modi has stopped working and when
I looked at it in the Audio-Midi Settings it had changed its sample rate to 88200. Very strange.
Regards,
l0rdr0ck