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MDAC first listen (part XIV)

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I've never experienced an issue like you have described - can you try a second MDAC in your system (from the dealer)?..

I really love my M-DAC and wouldn't return it. These bugs are annoying but I do not want to buy another M-DAC because it's an awful lot of work to return it just to test it.

I know this is not a problem of the M-DAC itself but of it's firmware. Maybe you could send me a new firmware so I could try it.
(Why should the M-DAC automatically set the volume to -80dB?)

Maybe it's a good idea to enable the USB module of the M-DAC just if it has successfully booted?

Is there any way to install an old M-DAC (factory) firmware with the Mac?
I tried to reset the M-DAC to the default but the firmware I installed from wikkii is still there.
 
I really love my M-DAC and wouldn't return it. These bugs are annoying but I do not want to buy another M-DAC because it's an awful lot of work to return it just to test it.

I know this is not a problem of the M-DAC itself but of it's firmware. Maybe you could send me a new firmware so I could try it.
(Why should the M-DAC automatically set the volume to -80dB?)

Maybe it's a good idea to enable the USB module of the M-DAC just if it has successfully booted?

Is there any chance to install an old (factory) firmware on the Mac?
I tried to reset it to the default but the firmware I installed from wikkii is still there.

"Reset to default" will not restore to the original shipped software version - to update the software, just upload any version from the Wiki....

Are you saying that upon each power-up and the MDAC does not recall its last volume setting and defaults to -80dB?

You don't have the Menu option "USB Volume" set to "Enable" do you?
 
"Reset to default" will not restore to the original shipped software version - to update the software, just upload any version from the Wiki....

Are you saying that upon each power-up and the MDAC does not recall its last volume setting and defaults to -80dB?

You don't have the Menu option "USB Volume" set to "Enable" do you?

The old M-DAC firmwares from wikkii are just available for Windows...

I don't have USB Volume enabled, it's set to Deny Control.

If no music is playing and I reboot the M-DAC the last volume I've set is chosen.

However if I play music and reboot the M-DAC the volume is set to -80dB. I can change that volume to any volume I want, but I don't hear sound coming from neither the XLR / Cinch nor the headphone output.
The really odd thing is that the M-DAC's input meter works perfectly, so I can actually "see" the volume of the music playing but can't hear it.
 
The old M-DAC firmwares from wikkii are just available for Windows...

I don't have USB Volume enabled, it's set to Deny Control.

If no music is playing and I reboot the M-DAC the last volume I've set is chosen.

However if I play music and reboot the M-DAC the volume is set to -80dB. I can change that volume to any volume I want, but I don't hear sound coming from neither the XLR / Cinch nor the headphone output.
The really odd thing is that the M-DAC's input meter works perfectly, so I can actually "see" the volume of the music playing but can't hear it.

looks like the problem i've experienced once with my mdac. I shut it down for 1 hour then it works again...
John tells me that it doesnt sound good. In fact he was true.
Few days after it fails again sometimes somehow randomly. Now it's in john hands for servicing (and sovereigning ;) )

Anyways you can try firmware A.07 which is available for osx on the wiki or settle a windows os on a virtualmachine using virtualbox to flash another one.
 
Ok, wow. I just installed the factory version (0.9) with a Windows computer.

Back to the Mac I nearly got a hearing damage.

Music playing at - 52dB at the M-DAC. Rebooting the M-DAC made it jump to +3 dB.

I really would like to try a firmware which enables the USB module just if the boot has finished.
 
Interesting. I have experimented with this yesterday, as I'm currently using the M-DAC as standalone DAC and I wanted to try out the pre amp functionalities. My setup is SBT (EDO with hub) > USB > M-DAC (VA.08). I've experienced the exact same thing you're describing, jonathanmueller: level meters are moving, but no sound can be heard. Few restarts...or noodling around with cables...or restarting the SBT and it works again. As you can hear, I wasn't exactly operating in a structural deducting debugging kind of way during that process. :)

Anyway, reverting to my previous setup, bypassing the pre amp, solves the problem for me. The M-DAC has been turned off and on more than 10 times, no problems. I'm mentioning it because it proves it might not be Mac or Windows related.
 
I recall seeing the message 'clearing USB buffer cache' (or something like that) during a startup at some point.
 
I have a similar problem with my portable DACS, when I used them with some players in windows. I guess it is quite common, if you are playing some lossless audio with a DAC. Maybe it's something about the software(system's or player's, I am not sure).
 
The old M-DAC firmwares from wikkii are just available for Windows...

I don't have USB Volume enabled, it's set to Deny Control.

If no music is playing and I reboot the M-DAC the last volume I've set is chosen.

However if I play music and reboot the M-DAC the volume is set to -80dB. I can change that volume to any volume I want, but I don't hear sound coming from neither the XLR / Cinch nor the headphone output.
The really odd thing is that the M-DAC's input meter works perfectly, so I can actually "see" the volume of the music playing but can't hear it.

Hi Jonathan Mueller,

From the very odd behaviour you describe, I can only guess at some obscure hardware issue, maybe the Brown-out / Reset circuit is not working correctly - you really need to have your MDAC looked at by a service centre.

If your thinking of upgrading to the MPAX later, then I can look at your unit when you return your unit too us for the upgrade.

We have over 10,000 MDAC in the field now - this is not directly a software related issue - but some odd hardware bug that is effecting the software indirectly (as I say the Brown-out / Reset circuit springs to mind).

I'm sorry for your issue,

John
 
If your thinking of upgrading to the MPAX later, then I can look at your unit when you return your unit too us for the upgrade.

Hey John,

I don't think I will send my unit for reparation.
What exactly is a MPAX?

I really can't imagine that this is a hardware related issue as some here in this forum already have reported this odd behaviour.
Maybe it's a better idea to send us some new firmwares which could fix the bug. (I think this will be not as much work as the repairing process & it will (maybe) help not just one who gets his device "repaired" / exchanged)
I'm quite sure that the bug is gone if the USB module of the M-DAC is activated after M-DAC's boot process. (Described at the end of this post)
What do you think? I really would like to help you.

Have you tried the M-DAC with it's latest firmware & Mac OS 10.6.8?


Why it would help to activate the USB module AFTER successful boot:

The only difference between restarting the M-DAC with music playing and without any USB signals is that the unit receives signals while booting in one case, in the other not.
If the unit is receiving signals while booting it will later fail (at least in my case) to play any signals.
So, enabling the USB module after booting will have the same effect with music playing as without:
The M-DAC will first receive the signals if it has booted. (That's because the computer can't select the M-DAC as an output device because it's not yet recognized.)
Does this make any sense?

(That's the only logical issue I can imagine) :)
 
Hey John,

I don't think I will send my unit for reparation.
What exactly is a MPAX?

I really can't imagine that this is a hardware related issue as some here in this forum already have reported this odd behaviour.
Maybe it's a better idea to send us some new firmwares which could fix the bug. (I think this will be not as much work as the repairing process & it will (maybe) help not just one who gets his device "repaired" / exchanged)
I'm quite sure that the bug is gone if the USB module of the M-DAC is activated after M-DAC's boot process. (Described at the end of this post)
What do you think? I really would like to help you.

Have you tried the M-DAC with it's latest firmware & Mac OS 10.6.8?


Why it would help to activate the USB module AFTER successful boot:

The only difference between restarting the M-DAC with music playing and without any USB signals is that the unit receives signals while booting in one case, in the other not.
If the unit is receiving signals while booting it will later fail (at least in my case) to play any signals.
So, enabling the USB module after booting will have the same effect with music playing as without:
The M-DAC will first receive the signals if it has booted. (That's because the computer can't select the M-DAC as an output device because it's not yet recognized.)
Does this make any sense?

(That's the only logical issue I can imagine) :)

I'll ask Dominik to take a look to see if he can recreate the issue,

John
 
...The only difference between restarting the M-DAC with music playing and without any USB signals is that the unit receives signals while booting in one case, in the other not.
No, that isn't the only difference!

There is a hole in the ground here. If you restart the MDAC with music playing via the USB input, that is almost certainly going to upset the USB port feeding the MDAC. Unlike an SPDIF input, USB is two-way traffic and if the highway is shut down in a somewhat unpredictable way by turning the receiving device off and on again, this can have consequences ranging from nothing, to crippling of the USB port in question until the host computer is restarted. And this latter, at least on a Windows system, can make the entire system unstable if the OS attempts to communicate with a USB port that has been put into a semi-responsive state.

A USB device has to be powered and stable before any data transfer is possible. If you simply 'pull the plug' on a USB data transfer while running, it hardly seems reasonable to expect the process to recover, unaided.

I use Windows PCs and all the above is demonstrably true. Perhaps the Mac world has more idealistic expectations.
 
Switching to standalone didn't solve the problem for me. Did some tests with this:

While the SBT was playing I have restarted the M-DAC 10 times. 8 times it started playing as soon as it was started up. The first time when it didn't, it showed a 'flushing buffer 3 sec') message, then moving meters but no sound. After I rebooted it again, it worked properly. The other time it didn't work I had to reboot as much as 5 times before it started playing again. The 'flushing buffer' occurred at the third reboot, but didn't solve the problem this time.

Did another test turning the SBT 'off' (using the on screen 'standby' knob), rebooting the M-DAC and trying the play the SBT again: even more failures this time.

Strangely enough I have been running succesfully for the past few days (must have chosen the right order of turning the equipment off with my Harmony).

Hard to see a pattern here, in other words. Maybe it's about picking the 'right' moment during the buffer?

Setup: SBT (USB, EDO) > M-DAC (standalone mode). At least 5 seconds between each reboot.
 
I use Windows PCs and all the above is demonstrably true. Perhaps the Mac world has more idealistic expectations.
Yes, as you know with Mac it works perfectly and we (mac people) dont have to know anything about how....

More seriously if you restart the mdac with music playing the player must switch to another output and then eventually come back to mdac when usb recognition has been achieved (i.e. when the drivers are ok and the device registered as a coreaudio component). I cant imagine the usb controller as a blind sender as serial or old parallel ports used to be. In other hand if it works effectively like this you can enter into the black hole of fuzzing the device (which is a commonly used hacking technique for hardware devices).

When my unit has an issue which looks like this one my mac was running Mountain Lion 10.8.0. I think we cant ask dominik to test firmwares on any os/hardware combination but to trust in the specifications of interfaces.


Hope that could help
 
Setup: SBT (USB, EDO) > M-DAC (standalone mode). At least 5 seconds between each reboot.

I'm using a similar setup, SBT (EDO) > USB Hub > USB Isolator > M-Dac (Pre & DAC)

I've taken to leaving my M-Dac on...

To reliably re-instate the USB link, both SBT and M-DAC should be turned off, then power up the M-Dac, followed by the SBT, and not just SBT standby mode, I think that's where things get a little confused.
 
Yeah, I'm thinking about leaving it on too now. I'm surprised how many times the process succeeds with the Harmony switching things off though. :)

What does the isolator do? (oh, there's non powered hub in between in my setup as well)
 
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