New AES3/USB interface?

I think your thought process is correct with regards to the I/O. From what I’ve read it seems that the MC looks for a reference- and whether that’s via an AES/SPDIF input or an individual BNC Word clock input (rear input connections) it would correlate to the selectors on the front panel. My assumption was that if you’re using USB for signal and clock reference none of the others would need to be selected. I don’t understand why it would want another timing source if only USB was used. I’m assuming you had the Mac and USB all connected with a source playing while setting up the MC3? My question to Mutec would be “why do I have to select other input references to have audio throughput when I’m using USB as a source”.

BUT- there might be something in all of this that means the MC3 is outputting something strange to your speakers DAC and/or signal network. Just my guess.

The USB cable should be rated for class 2 transmission, that will at least solve one drama. The other possibility is the cpu is just busy at the wrong time and interrupts USB.

Many other causes, loose corroded connections. 

Try a different player, jriver or Audirvana?

.

Inexpensive usb isolators.  Macs would introduce high AC noise and ground loops.

$50 but not every DAC likes them.

@designsfx

After looking at the Mac specific instructions, I noticed this. Looks like everything displayed on the front is normal and expected.

I may try a hi-end USB cable and see if that changes anything. Will also most likely get that Matrix Audio X-SPDIF 2 and compare results.

"Hardware Setup

• Power up the MC-3+USB via the switch on the rear of the device.
• The MC-3+USB has several modes of operation, but for audio re-clocking you need to set it to »INTERN« & »RE-CLK«.
• Press the MENU button once (LEDs flash) and use the SELECT button to cycle through the MODE menu until the top (INTERN) and bottom (RE-CLK) LEDs in the MODE column both light up.
• As a result the top three LEDs in the REFERENCE menu should light up at once as the default setting and indicate that the USB input has been selected as audio input."

I might have a different reference than you- I pulled the manual off their web site a couple of weeks ago. The setup notes in the copy I have state the following:

»INTERN« & »RE-CLK« (Internally referenced Audio re-clocking)
The »INTERN« and »RE-CLK« LEDs will light up when »RE-CLK« mode is selected, indicating that the re-clocking mode based on the internal clock oscillator is now active. As a factory default, »USB-PCM« and »USB-DSD/DoP« are selected as the first available audio reference in the »REFERENCE« menu (the first three LEDs in the column are illuminated). Press the menu key once and you’re entering the »REFERENCE« menu. Toggle the »SELECT« key to select one of the four available audio referen- ces: USB (PCM & DSD/DoP), AES3/11, S/P-DIF op, S/P-DIF bnc. This will now be re-clocked with the internal ultra-low jitter clock signal, format-converted, and passed on to all audio outputs with the same sampling rate simultaneously.

Anyway- sorry I couldn’t help you out more on this but I am interested in these units as I’m thinking about testing it to distribute signals from my playback server to multiple DAC’s. Hoping it would be the right piece for the application.