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Can two DACs interfere with each other?

post #1 of 13
Thread Starter 

I did a search and my problem didn't come up. However i figure with all the expertise present in these forums, somebody might have an answer...

 

I recently got an NAD amplifier with a MDC DAC built into it. It sounded great running from my laptop via USB.

 

When i'm on the move i use a FiioE7 DAC with my headphones. However after i the first time plugged in the Fiio E7 into my laptop via the USB, the laptop was no longer able to recognise the MDC DAC from the amplifier, even after the Fiio E7 is unplugged.

 

But here comes the strange part: If i plug in both DACs at the same time, after about 30 seconds, the MDC DAC is recognised and works properly again (until is is turned of again, at which point i have to repeat the process to get it working again).

 

So i suspect there is some kind of interference going on between the two DACs, but is that even possible?

 

PS:

Running windows 7, i have of course already tried installing/unstalling the custom NAD drivers and all.

post #2 of 13
Quote:
Originally Posted by Misconstruction View Post
I did a search and my problem didn't come up. However i figure with all the expertise present in these forums, somebody might have an answer...

I recently got an NAD amplifier with a MDC DAC built into it. It sounded great running from my laptop via USB.

When i'm on the move i use a FiioE7 DAC with my headphones. However after i the first time plugged in the Fiio E7 into my laptop via the USB, the laptop was no longer able to recognise the MDC DAC from the amplifier, even after the Fiio E7 is unplugged.

But here comes the strange part: If i plug in both DACs at the same time, after about 30 seconds, the MDC DAC is recognised and works properly again (until is is turned of again, at which point i have to repeat the process to get it working again).

So i suspect there is some kind of interference going on between the two DACs, but is that even possible?

PS: Running windows 7, i have of course already tried installing/unstalling the custom NAD drivers and all.

You can manualy set which output to use. Go to the win 7 control panel, in control panel click on "sound", in the "Playback" tab, you can select output.

post #3 of 13
it sounds like the USB ports aren't supplying enough power to run both the devices simultaneously. You should have no problems running multiple DACs off the same computer as long as the power requirements are met. Easiest thing would be to try different USB ports in the computer, and if that proves unsuccessful, a powered USB hub.
post #4 of 13
Thread Starter 

Thanks for the replies:

 

@purpleangel: The problem is that the MDC DAC does not appear in this list (or in the list of devices in the control panel).

 

@evilhippie: The MDC DAC has an external power source, so i don't think that is the problem.

post #5 of 13

2 DACs, or audio devices in general, would not interfere with each other. Windows vista.7 are more then capable of handling multiple sound, video, and display devices. 

 

With both devices plugged in, look at your device manager and see what it reports for both devices. Is one of them showing up with an error? does one of them completely disappeared from the device manager when both devices are plugged in? 

 

If one of the devices disappeared from the device manager with the other plugged in, something screwy is going on with the laptops USB systems. 

post #6 of 13

Well, power can be the only issue.

Otherwise, the two DACs are mounted on separate ports, so there shouldn't be any problems.

post #7 of 13
Thread Starter 

The MDC has its own power source, so that power should not be a problem.

 

The NAD MDC DAC does not appear on any list, either in sound or devices.

post #8 of 13
Is there any chance the issue exists separately from your PC, and with the NAD device? Or perhaps the USB cable? Have you tried this with another PC or with different cabling? (It doesn't have to be exotic, just different; unplug your printer or whatever if you must).

Does it seem to matter what port the devices are connected to? (I'm guessing not).

Does the Fiio have any drivers associated with it, beyond the Microsoft packages?
post #9 of 13

If you're talking about the 'devices and printers' menu in Win 7, better take a look at the device manager. That'll show you whether or not a usb device is mounted on a port. If there's some device shown, but it is not recognized properly, then its probably a driver issue.

Also, try the other way round. If you plug in the MDC first and the Fiio afterwards, does the issue still remain?

Other than that, try using it on different ports/ PCs, its possible there's a faulty port.

post #10 of 13
Quote:
Originally Posted by proton007 View Post

a faulty port.

Also a really good idea and very real possibility.

At this point I'd really be troubleshooting it as a hardware problem, until you can rule that out, and then you can whine to NAD to fix their drivers or whatever. tongue.gif
post #11 of 13
Thread Starter 

Thanks again for all the replies: Now the NAD DAC has actually completely stopped working completely...

 

- The Fiio E7 and my USB printer works from all USB ports and with all combinations of cables. I think that rules out any faulty wiring

 

- When in the device manager, only my laptop sound and Fiio E7 shows up under sound devices. There is no unidentified device connected anywhere. Interestingly, the NAD DAC shows up in the add older hardware option. However this does not change whether the NAD DAC is plugged in or not...

 

- The Fiio E7 runs on the standard (?) microsoft driver. The NAD had a custom driver by NAD electronics installed before it started malfunctioning. However, running it with just the standard microsoft driver didn't fix the issue.

 

 

This leads me to conclude there is two options left:

 

- Somehow the drivers are messing eachother up - even though i don't know how that's possible...

 

- There is something wrong with NAD DAC hardware - always a possibility.

 

I'll borrow a friends laptop to test this, that should solve the issue.

 

In any case i have a lifetime warranty from my local vendor, so that should be able to help fix or repair the device.

post #12 of 13
I'd be looking at the NAD as the culprit - either it's drivers, or the hardware itself.
post #13 of 13
Quote:
Originally Posted by obobskivich View Post

I'd be looking at the NAD as the culprit - either it's drivers, or the hardware itself.

 

Most likely. Checking on another pc/laptop will confirm this.

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