[jdkJake]

What shall I measure btw?


Voltage in reference to ground (+0)?


Resistance to ground?

As we have come to expect around here, TomB continues to provide excellent, timely advice and an important warning. You would do well to heed that advice (and the warning).

I think you should most definitely perform the power-off checks he recommends before proceeding to attempt any power-on measurements. It bears repeating, power-on measurements are always risky, especially with traces this small. The possibility of shorting something out by accident is always present and great care needs to be taken when performing them so as not to damage the part. Please do not attempt them if you feel uncomfortable in any way. I would hate to see you take out one of your DAC's by having you attempt a task you are not completely comfortable in performing.

 

[Eyediver]

Ran resistance checks to ground with all pins and they are effectively identical between the two DACs
Then powered, I ran voltage checks to ground and they match up there too.
 
So... just to recap... the unit gives the detection sound when I plug and unplug it but does nothing more on my computer.  Sound still continues to play out of the onboard sound card and does not cease like it does with the functioning DAC.

 

[tomb]

Quote:

Ran resistance checks to ground with all pins and they are effectively identical between the two DACs
Then powered, I ran voltage checks to ground and they match up there too.
 
So... just to recap... the unit gives the detection sound when I plug and unplug it but does nothing more on my computer.  Sound still continues to play out of the onboard sound card and does not cease like it does with the functioning DAC.

Can you manually switch the PC's active sound source to the GrubDAC?  No one says it's supposed to "claim" itself as the active sound source when connected.  That action with your other GrubDAC may be a coincidence as your PC distinguishes between one DAC and the other.  If the resistances and voltages between the two DACs are the same, I can't see any reason that the second wouldn't work - but automatically asserting itself as the active sound source when connected is not part of its features. 

 

[Eyediver]

That was it TomB!  It works fine.. I just had to select it in the control panel.  Seemed strange that the other one would
"claim itself" and this one wouldn't.
At any rate, thanks mightily to you TomB, JdkJake, Cobaltmute and Particleman14!
Thanks to TomB and Cobaltmute for the design and distribution.

 

[jdkJake]

Great news eyediver.

Glad to hear that mystery is finally solved. Enjoy your DAC's!

 

[tomb]

Quote:

That was it TomB!  It works fine.. I just had to select it in the control panel.  Seemed strange that the other one would
"claim itself" and this one wouldn't.
At any rate, thanks mightily to you TomB, JdkJake, Cobaltmute and Particleman14!
Thanks to TomB and Cobaltmute for the design and distribution.

Yeah, I don't know exactly how - maybe there's something akin to a MAC address somewhere in the PCM chip.  I connect two GrubDACs and two BantamDACs to my primary PC all the time.  For some reason, it recognizes all of them discretely, but the # designation in the Control Panel (3-USB Audio DAC, 4-USB Audio DAC, 4-BurrBrown Japan PCM 2702, etc.) stays the same, no matter in what order I disconnect/reconnect them.
 

 

[Oeufdepoire]

Hello there,
 
I hope you'll be able to help me. I have a problem with the output of my GrubDAC. The left output is in contact with the ground, so as right output. Left and right output aren't in contact on the other side. The resistance between LO and Groung, which is roughly the same as between RO and Ground, is approximately 80 000 ohms.
The GrubDAC doesn't deliver any sound to the headphones, I think it's because of the "short" cited above.
 
In fact, the GrubDAC worked before. I tried three female jack connectors for the output, and, sometimes it worked, sometimes not.
I checked and cleaned all my solders at least five times. So, in your opinion, what's wrong?
 
Thank you.

 

[jdkJake]

Can you provide pictures of the top and the bottom of the board?

Clear, sharp and well-lighted pictures will help to diagnose the problem.

 

[Oeufdepoire]

I didn't fully explain what's wrong with the outputs : when I measure with my ohmmeter the resistance between both LO and Ground, and RO and Ground,  the resistance increases from 0 to 80 kΩ within , let' s say, 45 seconds. What' s this ?
 
I re-soldered a new cable to the jack (it still doesn't work), that's why some solders are dirty. I'm going to clean them again, and test.
 
Also, pictures :
 

 

[Avro_Arrow]

When you are measuring the resistance from LO to GND and RO to GND, all you are doing
is charging the output capacitors. Thats why it starts at a low value and slowly increases.
What you are seeing is normal there.
 
Does the LED light and do you have 3.3 volts at the test point?

 

[Oeufdepoire]

The LED lights and I have 3,28~3,29 V at the test point.
 
When I plug my phones while the DAC is plugged, I don't hear the caracteristical "clip" from the drivers produced by the short-circuit at the jack. Is it normal ?

 

[Avro_Arrow]

You said that this was working before and now does not?
Is it still recognized by your computer?
Is it possible the volume is just turned down?
Could the problem be with the output jacks?
 
The voltages seem fine.

 

[Oeufdepoire]

The DAC doesn't "produce" sound.
It is recognized by the computer, and its LED lights.
It's not a volume problem, I've tested and messed with foobar2000's volume, Windows' volume, and all the "mixers" in the task bar.
I've tested several output jacks. My multimeter says they're all fine, all the contacts are contacting.

 

[tomb]

Quote:

The DAC doesn't "produce" sound.
It is recognized by the computer, and its LED lights.
It's not a volume problem, I've tested and messed with foobar2000's volume, Windows' volume, and all the "mixers" in the task bar.
I've tested several output jacks. My multimeter says they're all fine, all the contacts are contacting.

Is it possible your computer's sound output got switched to another device?
 
Do you go into the File-Preferences-Playback-Output menu of Foobar and check to make certain the proper "Output Device:" is selected?

 

[Oeufdepoire]

Quote:

Do you go into the File-Preferences-Playback-Output menu of Foobar and check to make certain the proper "Output Device:" is selected?

 
Yes I do. The device is called "Haut-parleurs (USB Audio DAC  )".