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post #31 of 36

Unfortunately, this thing has a horrible USB implementation.  90% of the time I can't even get it to connect to either my Macbook Air or my PC.  It takes a series of plugging and unplugging both power and USB from both ends, turning off and on again the computer and the DAC, and lots of stressful yelling to get it to work.  Then, 100% of the time, a Windows bluescreen ends my listening and we're back to the plugging and unplugging.  At least on the Mac it stays connected once it's connected and mostly works (a couple of dropouts here and there with Audirvana), but that's not enough for me to keep this thing.  It's too bad, because it sounds really good when it works.  

 

Maybe mine is bad.

post #32 of 36
Quote:
Originally Posted by cizx View Post
 

Unfortunately, this thing has a horrible USB implementation.  90% of the time I can't even get it to connect to either my Macbook Air or my PC.  It takes a series of plugging and unplugging both power and USB from both ends, turning off and on again the computer and the DAC, and lots of stressful yelling to get it to work.  Then, 100% of the time, a Windows bluescreen ends my listening and we're back to the plugging and unplugging.  At least on the Mac it stays connected once it's connected and mostly works (a couple of dropouts here and there with Audirvana), but that's not enough for me to keep this thing.  It's too bad, because it sounds really good when it works.  

 

Maybe mine is bad.

Sorry for the delay in answering this. We wanted to make sure we could duplicate the issue you had.

 

First let me say that hundreds of these units have been sold without issue all over the world. What we have found with BMC is that the grounding scheme in some homes in the US can cause some issues. Power Outlet Grounding schemes in Germany are very tried and true. It is part of their safety standards. In the US this standard is very lax. Some homes dont have true grounding schemes. Especially old homes which may have had 2 prong outlets at one time and then changed to 3 prong. Ground cheaters can also cause issues. In the US only 3 reports of the issue you had have been reported. Unfortunately you and a second customer of mine after your sale had the same issue. Here is what BMC found:

 

Here a short description of what we found regarding the PureDAC's random connectivity issues:

Problem Description:
In some surroundings the PureDAC is unreliably connecting via USB.
This problem is not related to drivers and the same unit works well in most other geographic locations.

Analysis:
The hardest part of such problems is to reproduce them in a way that there is clear before and after.
We succeeded triggering the problem by using a simulated power supply and remove the noise filters. Within this condition we found very unreliable USB handshake.
We found that the noise is avoiding a complete discharge of the rather big logic power supply and the reset-sensitive XMOS USB interface fails to start-up properly.

Applied solution:
We added a discharge load to the unregulated power supply, ensuring a complete discharge within 3 sec even under noise conditions. This way the problem was resolved for a test group of 20 units.

Another issue might be excessive electrostatic discharge at the USB port, emerging from poor computer power supplies and poor grounding. We have discharge protection build in, but in some excessive cases the protection wasn't sufficient. We suggest to reduce hot-plugging. Make sure to connect your USB while both the computer and BMC is off. This issue is not a rare one. Over many years now of us selling USB Dacs, we have encounter computers shorting out USB cards on several brands we sell. The same issue can happen when you swap speaker cables from one speaker to the other while the amp is still on. Never a good idea. Computers have spoiled us with the Plug and Play nomenclature. 

 

One other issue I have run into is driver corruption. I test and play with a lot of USB devices here at Moon Audio. And after loading about 15 different DAC's and all there associated driver files I started to run into computer issues. Like the Blue Screen your are reporting. I had to wipe the computer and reinstall the operating system. Not fun when the computer is your main computer. I now have a dedicated machine just for Dac testing so when these corruptions happen there is minimal down time in reinstalling the OS.

 

Anyway BMC is on top of the issue and is implementing into the latest production batch. The fix is also easy to do on existing units in the field that become problematic. But like I said on 3 units in the US have had the issue.

Thank You. Drew Baird, P.E. Moon Audio 308 Chrismill Lane Holly Springs, NC 27540 919-649-5018 drew@moon-audio.com http://www.moon-audio.com Moon...

Reply
post #33 of 36

Thanks for forwarding our information exchange Drew!

 

Most of this points are common for most USB DAC models.

 

I would like to add one more point you brought up:

Since Microsoft refuses to follow the USB 2.0 audio standard (unlike MacOSX and Linux) you need to install a driver for "explaining" a highres USB DAC to the operating system, so it can be used.

If you change between a lot of USB DAC for sure you will run into trouble. This is not because other DAC with XMOS USB chipsets are incompatibe, but because of build in license restricion trouble. During the installation of the TUSB driver you have to connect the DAC so it can read and confirm the PID (USB identification) and block any other DAC.

Add the fact that a clean uninstall on Windows is rather unlikely and you can look forward to the next clean install.

 

For people using a lot of DAC Mac or Linux are doing the better job, although Mac still lags behind all others concerning sound quality until there is a solution bypassing the core audio.

However a normal user won't run into such problems and can enjoy the pretty good Windows solutions without worry.

 

Hope this helps clarifying some mysteries.

 

Carlos

post #34 of 36
Quote:
Originally Posted by cizx View Post
 

Unfortunately, this thing has a horrible USB implementation.  90% of the time I can't even get it to connect to either my Macbook Air or my PC.  It takes a series of plugging and unplugging both power and USB from both ends, turning off and on again the computer and the DAC, and lots of stressful yelling to get it to work.

 

Maybe mine is bad.

A 7 months old post but I have the same "fun" here! I bought the PureDAC one week ago and use it for my Daphile (based on Gentoo Linux, using the Squeezelite player) via USB.

 

The XMOS USB interface was one of the reasons to buy the PureDAC. My (unfortunately already sold) Matrix X-Sabre worked great with the Daphile nettop via USB. They always found each other immediately, so I am pretty disappointed about the connection trouble between the PureDAC and the nettop now. This morning, it took ages to connect the PureDAC with the Daphile nettop. Both devices were off at night. And then, when you finally see the "HR" and later the "44" sign in the PureDAC's display, it doesn't mean that it always works then! There is sometimes no sound. You have to switch off/on the PureDAC again to get the sound.

 

Quote:
 Maybe mine is bad.

That was my thought, too. The German B.M.C. Audio support mailed me something about a prepared update. Not sure if I can wait till it is available. Maybe my PureDAC is a 2013 model? I find the sound quality of the PureDAC amazing (and I like it as a preamp for my active speakers very much) but I need a quick USB "handshake" similar to the Matrix X-Sabre or the Oppo 105.. Also as "waf" for my gf.

 

Mario

post #35 of 36
FWIW I had similar problems with my (2013 - among the first delivered I believe) PureDAC and Mac Mini USB. I went back to optical then later re-tried after reading carefully the information in the manual.

I'm not sure exactly which suggestion solved the problem, but think a poor-quality USB cable was one part of it.

May not be the same problem as yours but in my case there have been no problems since...
post #36 of 36
Quote:
Originally Posted by AiDee View Post

FWIW I had similar problems with my (2013 - among the first delivered I believe) PureDAC and Mac Mini USB. I went back to optical then later re-tried after reading carefully the information in the manual.

I'm not sure exactly which suggestion solved the problem, but think a poor-quality USB cable was one part of it.

May not be the same problem as yours but in my case there have been no problems since...


I have a Nuforce Impuls USB cable. Nothing expensive but it should do its job. I wonder why my PureDAC still had this problem though the fix was already available in January.

Well, I bought the Oppo HA-1. It arrived yesterday. USB handshake works as expected.

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