New AES3/USB interface?

@hedkase 

Just wondering if you were ever able to get this sorted out and what was giving you the problem?

@designsfx 

No, worries. I appreciate the attempt!

BTW -- Mine was taken from the Quick Start Guide I downloaded from their website today. Might want to check that one out and compare.

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.
 

@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."

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

$50 but not every DAC likes them.

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?

.

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.

@designsfx 

I've tried just about every configuration available. This appears to be the only setting that gives me audio.

Also, I'm unable to have nothing selected for the Reference column and at no point am I able to change anything in the Clock Out column. When I scroll through the settings, that column is always skipped. I wonder if that setting is tied to a particular input/output of the device?

@hedkase-

Ok- thanks for the pic. I may be guessing here but from what I’ve read in the manual it looks like you might have missed a step when setting this up. If not- my fault but it won’t be any worst than it is now!
Have you tried “DE-selecting” the three reference selections and setting the clock output selector to the max sample rate that either is sent via usb OR that of the DAC within each speaker?

It seems that by having the three selections on the reference input column selected the unit is expecting a clock reference from the associated input on the rear of the unit. The manual is not very explanation of just how far the USB input will take you but it seems you’re missing a clock rate (unless that comes on when the unit is operating of course). 

@designsfx 

I've tried all the settings. The only mode I get audio from is INTERN/RE-CLK. I unfortunately don't know much about this unit. It was a means to use these monitors with my desktop in my office.

MC-3 settings

@hedkase 

is the MC3 set to act as a clock generator or distributor?

@designsfx

My Mac does see the MC-3. Roon shows the MC-3 as the endpoint in the system.

It is a very odd issue and its driving me nuts ;)

I guess I can try that Matrix Audio X-SPDIF 2 and see if the change in hardware changes anything.

@hedkase-

I would be very surprised if it were cable quality- I’ve pushed $2 USB cables into video processors that were doing more work than that without issue. It’s a weird problem. 
Is the Mac the Master and does the Mac see the Mutec as the device on the other end of the USB interface OR does the Mac see the PMC on the other end of the USB (device/midi control in Mac OS)

@designsfx Ah, I assumed you meant sample rate change from track to track.

There is no other hardware other than the MacStudio, Mutec MC-3 and the PMC monitors.

I did just hear back from Mutec. They suggested maybe the USB cable wasn't allowing for enough power but I'm using external power so that's a moot point.

I wonder if a higher quality USB cable is necessary?

@hedkase 

This is kind of where I was going when I suggested sample rate change- perhaps I should have worded it as losing synch or not being locked. I wonder if you have something going on where the clocks are losing synch?

You mentioned a mix- is this a DAW setup? Are you running any memory intensive plugins or seeing large latencies in any other way? Just trying to learn from your experience here as I’ve not used a monitor with internal DAC before.

@rms456 

any idea why the signal would be lost?

This appears to occur randomly. Sometimes with no music playing, other times in the middle of a track. Sometimes it’ll not happen for a week, or it’ll happen several times a day.

The Mutec will mute when the signal lock is lost,  this is probably normal, input from Mac playing up?

After looking at the recommendations I've realized both are too large for my desktop studio setup. I may give this Matrix Audio unit a go. Has anyone heard anything good/bad?

X-SPDIF 2

@designsfx 

yah, USB from Mac to Mutec is how I've got it. The reset is strange. It'll start with one monitor then move to another, then the last. With each one appearing to power down and back on.

Like I said, these PMC units have been replaced twice over. And oddly enough, sometimes this occurs when I'm not playing audio but monitors are powered on and still connected to the Mutec -- but is mostly noticeable when music is playing, typically mid song.

So to answer your question, I never notice it when sample rates change.

@hedkase-

Just out of curiosity- what happens when the reset you’re describing occurs?
I assume you’re sending USB from Mac to Mutec- does a sample rate change ever trigger this? 

Only one AES for me. The PMC speakers run in a "daisy chain" configuration. Thanks for the recommendation. I'll check out those other brands.

I brought this issue up with Mutec directly but they appeared to be less than interested in investigating the issue.

I believe the Mutec has two AES outputs- one XLR and one BNC. The reset thing is an interesting problem though. Following because I’m thinking of buying an MC3+USB.

How are you connecting because the Mutec only has a single AES output and the speakers need dual AES inputs. Do you connect the second stereo channel via ethernet cable?

Denafrips and Audio GD make similar units to the Mutec.