Issues with ALIX / Voyage MPD

[elcraigo]

John,
I'm using the SPDIF (optical), with an older CD player.
CD player OFF->ON, DAC OFF->ON: 44.1
or
DAC OFF->ON, CD Player OFF->ON: 44.1

CD player ON->OFF, DAC ON: 44.1 or 192, 192 most of the time
CD Player ON, DAC ON->OFF->ON: 44.1
CD player OFF->ON, DAC ON: 44.1

I'm glad to run any other test. I do have win7 and a couple different flavors of Linux. I haven't tried a USB connection yet.

Craig
 
 

[Doc B.]

Just to clarify, the issue is not directly related what the display reads at startup. That's going to depend upon what it's connected to (or not connected to). The issue is that the 48K based sample rates are not available via USB at times, and that seems to require a reboot of the DAC.

We have been able to reproduce the glitch on both warm and cold DACs fed by a MAC mini. The consistent sequence for creating the glitch is switch input to SPDIF, power up DAC, plug in USB cable, then switch to USB input. The consistent sequence for fixing it is power down DAC, wait at least two minutes. Be sure input set to USB first, USB cable plugged in, power up DAC.

[2wo]

I have been unable to duplicate this issue on my Linux box.

Yesterday I had the power go out for about 4 hours. I abandoned ship so when it came back up, everything booted up on its own and I did not play anything. Tonight, after reading this thread, I looked and the DAC read 384.

I played a 96k file and all correct. I switched back and forth between 96, 44.1, 88.2 and 192k files, sometimes to the same file sometimes to another file of the same sample rate. some are wav, some are FLAC.

I get the correct sample rate displayed in every case...John     

[2wo]

Doc, I will try to reproduce per your above post and report back...John

[Doc B.]

The "switched to SPDIF, plugged into USB" glitch is reproducible on Windows, and solved the same way, power down, cable into USB, switch input to USB, wait for a minute or two and power up.

[Doc B.]

Josh is starting to set up a Linux box so we can see what happens. That will take a little time so we may not have much to offer until tomorrow.

[debk]

I am unable to try the fix at this time since my set up is torn apart for some remodeling.  I hope to have everything hooked up again by early next week.  I had tried the DAC on SPDIF before this occured so it seems to be consistent with what others are experiencing

Debra

[2wo]

I tried the The "switched to SPDIF, plugged into USB" and still have no trouble.

The only abnormality to report, is when I reached back to disconnect the USB cable. There was a slight static pop (still winter here, sigh) when I touched the back panel and this scrambled the display. It recovered on the next song.

If there is a specific sequence you would like me to try, I am game...John 

[John Swenson]

When it is set to S/PDIF is there a S/PDIF cable plugged in with a signal, cable plugged in with no signal or no cable plugged in?

The DAC itself carries no state when powered down, so a power down should fix any problem, but the capacitors can keep things going for a while, thus the wait two minute part.

Thanks,

John S.

[Doc B.]

For us the glitch is happening whether or not a SPDIF cable is plugged in - with or without signal. The two minute reset thing seems to be a solid solution. I think all we have left to address is Tom's issue with the Alix box. Josh just about has our Linux setup going. We're outta here in five, and we should be able to run some tests tomorrow.

[John Swenson]

I was able to duplicate the issue, and narrowed down what is happening.

When switching from SPDIF (or TOSLINK) to USB if the first song played over USB is the same family as the S/PDIF, everything is fine, USB can change families. BUT if the first song played over USB is a different family than SPDIF, USB is locked to the family last played on SPDIF.

This happens whether the SPDIF was there at boot or not. Starting up in USB, then switching to SPDIF, then back to USB will cause the problem.

Examples:
Power up in S/PDIF, play 44.1 song, switch to USB, play 44.1 song, everything is fine, can then play a 96 song.
Power up in S/PDIF play 44.1 song, switch to USB, play 48 song, display shows 44.1, sounds slow
Power up in S/PDIF, play 96 song, switch to USB, play 48 song, everything is fine
Power up in S/PDIF, play 96 song, switch to USB, play 44.1 song, display shows 48, plays fast

Since I don't have a Mac, I can only do some surmising here, but my guess is that if you have the audio-midi set to a sample rate with the same family as 44.1 (44.1, 88.2 etc)  you should be able to switch to say a CD player plugged into the SPDIF or TOSLINK jack which is playing CDs, ie 44.1. Even if you are using something like amara which can over-ride the sample, if the audio-midi is in the same family, the first thing the DAC sees is a connection to the same family, thus the USB will work fine. Someone else will have to do some testing on this to see if it really works this way.

This is a real live firmware bug, I will try and find and get it fixed soon.  There does seem to be a work around, if you are using USB exclusively, just make sure the switch is in USB before powering up. If you want to switch between SPDIF/TOSLINK and USB, make sure the first thing played on USB is in the same family as the last thing played on SPDIF. You may have do something specific with audio-midi settings under MacOS.

Doc will have to discuss the firmware upgrade policy when I come up with a firmware fix.

I don't know if this has anything to do with the issue seen with MPD. Please try disabling MPD and use aplay to see if the problem still exists.

John S.

[Doc B.]

Since this is a fairly minor issue with a very simple workaround (power down, switch to USB, wait a minute, power back up) we will include John's fix with the first firmware upgrade. That will probably happen when John cooks up one or two of the other firmware update goodies he has proposed.

[dw]

Just wanted to mention that I reproduced this on a mac by the methods mentioned.
I recall now that I had switched to toslink and back to usb, so my early issues with the dac were not due to
the dac being cool.

Thanks,
Dave

[2wo]

I tried Johns experiment on my Linux box with similar results.

With my CD player on SPDIF, 44.1K I can switch to USB, (Linux) at 44.1 or 88.2K and back with no issue. Switching to 192K displays 176., but will switch back to 44.1

If I play a 96k track and switch to SPDIF it displays 44.1 but sounds distorted.

To recover I have not had to power down, just play a 44.1 or 88.2k track before switching...John     

[fullheadofnothing]

I have put a fair amount of time into playing around with this issue.

If I am running a 44.1 file on the BluRay on S/PDIF or TOSLINK, and I switch to USB playing a 96 file, it will glitch out and go to 88.2.

If I then play a 44.1 file, I can switch back to the 96 file and it WILL WORK.

From this point on I can switch resolutions at will with no problems. If I go back to the S/PDIF input, it will have digital noise over the sound. This can be fixed by unplugging the power and plugging it back in immediately. Switching back to USB will work, AS LONG AS it is set to run a 44.1 file (note that it will remember whatever the last resolution played was). If it is not, it will require either a reset (this is the minute+ reset, the immediate one is only for clearing the digital noise on the S/PDIF), or playing another 44.1 file before the 48 derived ones will work.

I have also used 48 from the S/PDIF, and sometimes switching over to USB will glitch, and sometimes it won't

I have done this using an older version of Amarra on a Mac and aplay on the Debian box.