[tomb]

  Hi,

I just finished building my pupDAC and it can output sound through Windows, but there's a big problem. I've already set the pupDAC as the default device in Windows settings, but somehow the volume control on my taskbar does absolutely nothing to control the volume level. Pulling the slider all the way up or down makes no difference to the volume (all really loud), all while the grey bar keeps moving up and down (the green bar is not there since the volume is set to 0, but it's still extremely loud).

My pupDAC is linked to my headphones (I don't have an amp yet), so there's no way to control the volume level.
 
What can I do?

 

 
Try Left-clicking on the icon in the taskbar.  Select "Playback devices" from the pop-up context menu.  Select the pupDAC from the collection of playback devices in the pop-up window.  If you made the pupDAC the default device, it will have a big green check-mark beside it.  When selected, Right-click and select "Properties" from the pop-up context menu.  Select the "Levels" tab from the pop-up window.  Adjust it there and see if makes a difference.
 
Honestly, there is a bug (sorry - different "Windows Feature") in Windows 7 that manifests itself with the PCM2704/5/6/7.  It causes a conflict with the taskbar volume control when you make the device the default.  Texas Instruments has come out with the PCM2707C to combat this, but it is not supplied with pupDAC kits by default.
 
I've never had this problem with Foobar2000, which seems to be the standard for most folks.  It allows you to specify the source and there's never any issue.   I would search for other media players that allow you to do this, assuming you're not happy with Foobar2000.  The problem comes up when selecting a USB device as default in Windows 7 with a PCM2704/5/6/7.
 
Remember though - if you are adjusting volume through the operating system in any configuration with an off-board DAC, the USB is re-interpolated causing bits to be lost.  It's absolutely the wrong thing to do.  Pure sources like the pupDAC are intended to be used with an amp.  That removes the issue in every single case and ensures the best quality signal from the source.

 

[COOKIESnPIE]

Post deleted by user.
 
 

 

[tomb]

  Nope, the Levels did nothing. I plan to use this card for audio editing and mixing, not listening to music, so foobar is out of the question.

And BTW I just connected it to a HIFI and played it though the system, which was much better than directly connecting headphones to the pupDAC. Somehow, there's very little bass if you just plug in headphones directly - why?

Guess I'll have to build an amp soon... o_O
 

 
The pupDAC is not designed to output any significant power - no source-only DAC is.  Bass typically requires more power than any other frequency.
 
I'm sorry, but I have no explanation for why you can't adjust volume.  At the very worst with other customers, it has required specifically selecting the source when adjusting volume in Windows 7, but there has never been an instance where the volume can't be adjusted at all.

 

[adnc]

Can someone then suggest a DIY amp? Which maybe is organized and documented like pupDAC?
Ideally one whichs volume can be controlled by an application like MPD.
 
All those I found on diyforums are for headphones, but I would prefere an amp loudspeaker amp.

 

[tomb]

  Can someone then suggest a DIY amp? Which maybe is organized and documented like pupDAC?
Ideally one whichs volume can be controlled by an application like MPD.
 
All those I found on diyforums are for headphones, but I would prefere an amp loudspeaker amp.

 
If I understand what you mean by MPD, maybe you can find a different client interface that will select and manage sources independently of the OS.  Looks like a lot to pick from here:
http://en.wikipedia.org/wiki/Music_Player_Daemon
 
P.S. Search for "gainclone" if you want a DIY speaker amp.  Keep in mind that you'd still probably need a pre-amp (or headphone amp) if you're going that route.

 

[COOKIESnPIE]

Post deleted by user.
 
 

 

[tomb]

  How about an amp that powers both headphones and speakers? (Around 20W should be enough) Obviously, it has to be DIY.

a little off-topic at this point ...

 

[Stephonovich]

I believe U4 isn't functioning on my board.  All voltages check out except for both 3V3; they're at 0 VDC.  Vin receives 5V, as does ON/OFF.  GND is at 0 V.  Vout has 0 V, and BYP has about 0.9 V.  I've re-soldered the chip a couple different times, with no effect.  Can I get a new U4, or should I order it off Mouser?

 

[tomb]

  I believe U4 isn't functioning on my board.  All voltages check out except for both 3V3; they're at 0 VDC.  Vin receives 5V, as does ON/OFF.  GND is at 0 V.  Vout has 0 V, and BYP has about 0.9 V.  I've re-soldered the chip a couple different times, with no effect.  Can I get a new U4, or should I order it off Mouser?

PM me with your address.  I may have a spare.

 

[nini_knoxville]

Hey,
 
just finished mine. Soldering the SMD stuff was pretty easy. All voltages at the test points are good, but the right channel makes no sound at all. I can see no solderingbridges and all parts seem to be okay. Measured all resistors. Does anyone have an idea what to check next? The only voltage which isn't correct is the output voltage.. on the left channel, i get 0.9mV.. on the right.. nothing.. nc

 

[tomb]

  Hey,
 
just finished mine. Soldering the SMD stuff was pretty easy. All voltages at the test points are good, but the right channel makes no sound at all. I can see no solderingbridges and all parts seem to be okay. Measured all resistors. Does anyone have an idea what to check next? The only voltage which isn't correct is the output voltage.. on the left channel, i get 0.9mV.. on the right.. nothing.. nc

If it connects correctly to the PC and is recognized, then output issues are either in the DAC chip or the opamp.  Can you measure the pins on the opamp?  If the left and right input - pins 2 & 3 for Left Input and pins 5 & 6 for Right Input - measure the same, then there's something wrong with the opamp.  If they measure differently, then something's wrong with the DAC chip.
 
That's my guess, anyway - see if it indicates something and let us know.

 

[nini_knoxville]

  If it connects correctly to the PC and is recognized, then output issues are either in the DAC chip or the opamp.  Can you measure the pins on the opamp?  If the left and right input - pins 2 & 3 for Left Input and pins 5 & 6 for Right Input - measure the same, then there's something wrong with the opamp.  If they measure differently, then something's wrong with the DAC chip.
 
That's my guess, anyway - see if it indicates something and let us know.

Hi tomb,
 
thanks for the advice. After measuring the opamp, it looks like the DAC is the source of problem. I'll try to make some high def photos later so you guys may see an error which i don't.

 

[tomb]

 

  If it connects correctly to the PC and is recognized, then output issues are either in the DAC chip or the opamp.  Can you measure the pins on the opamp?  If the left and right input - pins 2 & 3 for Left Input and pins 5 & 6 for Right Input - measure the same, then there's something wrong with the opamp.  If they measure differently, then something's wrong with the DAC chip.
 
That's my guess, anyway - see if it indicates something and let us know.

Hi tomb,
 
thanks for the advice. After measuring the opamp, it looks like the DAC is the source of problem. I'll try to make some high def photos later so you guys may see an error which i don't.

OK - we'll take a look when you get the photos!

 

[nini_knoxville]

As promised the pictures:

 

 

[tomb]

Well, for the Right channel - the 3rd and 4th pins from the bottom-right of the DAC chip are the Right channel outputs (IORN and IORP).  I don't see anything wrong with those pins, but there does seem to be a "whisker" bridge starting from the 5th pin up from bottom right.  I don't know if that's really something and whether it would have an effect on just the right channel, but maybe.
 
You've done an excellent job of soldering, especially on the two big chips.  It's a reflective-photographic effect, I think, but it almost looks like some of the opamp pins are dissolved.

  I would not suspect the opamp at first guess, though, since it's fairly easy to solder compared to the rest of the PCB.
 
See if you can clear that whisker on the DAC chip and them perhaps apply a bit more heat with a few strokes of the iron on those bottom 3rd and 4th pins.