[Iorek]

So I've got an interesting problem, and this is probably a long-shot as it's a pretty specific issue. I've got a CEntrance DACmini CX (using USB input), and the playback is perfect except when I'm listening to music and browsing the web with Opera at the same time. When I'm browsing I'll get occasional pops and skips, and it's only in Opera. If I use Chrome or even IE there's no skipping. I've even tried playing music while benchmarking/stress testing and there's no issue. Also, it's not related to foobar2000. I tried iTunes and had the same issue.

I could be mistaken, but it seems like the skips occur mostly when I open or close a tab. There's a bit of a CPU spike during those times, but it's nothing big... anywhere from 0~7% CPU usage.

I've tried all the typical things such as putting foobar's priority to high/real time, increased foobar's memory caching to 100+mb, increased/decreased latency on both foobar and the DAC drivers, tried using ASIO output in foobar, etc, etc. I also tried switching LAN ports as well as switching USB inputs for the DAC. So far nothing has worked. I should also note that this occurs on both the headphone output and the RCA line out. I'm fairly certain the DAC is working perfectly fine, otherwise it would be popping all the time.
 
I tried using the DCP Latency Checker, and there is no visible latency when the pops occur. Latency remains in the green 100% of the time.

I'm probably going to reformat tonight to see if a clean Win7 install will help things.

Like I said, it's probably a long shot, but I'm hoping someone's had a similar issue or has suggestions regarding things I could try.

Thanks!

 

[NA Blur]

I sounds like there is some serious power issues when your PC is under load.
 
The first thing to check is to make sure the transition noises are turned off.  These are the sounds when you open windows, click on programs, etc.  Perhaps there is an issue with the CODEC when it has to translate two sounds at once over the USB line.
 
As for the power issue try another USB port.  Try one on the back of your PC and then one at the front if you have that option.  If the popping goes away use that port from now on.
 
Lastly be sure you have the correct bit depth selected for you device.  In Foobar 2000 for example I need to run 24-bit with my m903 to get the lowest noise floor.  You can select the bi depth in Foobar somewhere in the preferences menu.
 
One last thing to try is more compressed files.  Try some 320kbps files and retest.  If the popping goes away then the DAC is unable to handle low compression and run Windows CODEC at the same time.

 

[Iorek]

I always have Windows sounds turned off. I tried every USB port on my PC, including the front ones, and there was no difference. foobar2000 is configured correctly, and the file size makes no difference. I did notice, however, that using WASAPI out seemed to help a bit.
 
I did a complete reformat on friday, installing the latest drivers and software versions of everything... no dice.
 
I've also been using Chrome, and it too makes the DAC pop, just less frequently. I've also noticed that if I'm torrenting or doing something that maxes out my internet bandwidth, the popping is much more frequent while browsing. Though if I'm not using a browser there is no popping. It's like the motherboard can't handle the bandwidth spikes from the browser.
 
I ordered new cables from Monoprice. Not sure what I can do beyond that...
 
I was wondering though, would having a stand-alone network card help? It seems like it might...

 

[NA Blur]

It could be the DAC is picking up noise from your CPU or motherboard.  I know with when I use on-board sound I hear the "bleep-bloops" of the CPU and mouse.
 
The next thing I would try is unplugging things from the other USB ports and see if the sound subsides.  I have had mice cause issues like this before due to a abrupt current draw spike.
 
Try another CAT5 cable next.  Perhaps there is a shielding problem somewhere.
 
In the end it sounds like high levels of noise are being pushed onto the 5v rail and into the USB ports.
 
Steps:
 
1.)  Unplug everything else that is running off of USB and test again
 
2.)  Try another CAT5 cable
 
3.)  Turn down the volume knob on the DACmini CX to 60% and turn up the input volume on your PC  Perhaps the amp section of the DACmini is clipping.  If that seems to help or at least change the effects play with the volume levels on both until you get the popping to cease.

 

[Iorek]

After building my new PC there is no more popping from the DAC, so I guess I can assume it was my motherboard. Thanks for the help though, NA Blur.

 

[NA Blur]

I am going to guess it was a simple data transfer rate issue.  The cable / USB port you were using probably could not handle the data rate.
 
Did this occur listening to CD as well?
 
I am glad your new PC helped.  I know I prefer Windows 7 with USB 2 ports for USB DAC listening.