USB: static noise


#1

Hello,

I’m experiencing a static noise when connected over USB. It is not hum, it sounds like a radio static noise. Sometimes it gets louder.

My observations:

The system is dead quiet when no USB cord is connected to DAC (with all other cables connected and AMP powered up).
It is also quiet when only USB cord is connected with nothing on the other side.
The same static noise appears when the other side of USB cord is connected to any computer (I tried 3 different laptops on battery and plugged in).
Noise level is constant (pretty loud) and doesn’t depend on volume or music.
Even if DAC is on mute or off (from remote) there is still the noise.
One more interesting fact, when I connect DAC to computer with no PS audio drives the system is quiet. After I install drivers I start hearing that noise. I guess without drivers OS (windows 7 64bit) doesn’t recognize USB device and doesn’t send any signals to it?

Any ideas?
Thanks!
Denis.


#2

Have you tried a different USB cable? Some of the “esoteric” ones are perhaps not to official USB specs. It does rather sound like a software based problem, though. Could there be other drivers competing for access that could be disabled?


#3

Also if there’s any 60hz hum (and even if there isn’t) it could be a ground loop issue. Does the noise go away if the computer is plugged into the same outlet(s) as the rest of the audio system? If the power plug on any of your components is two pronged instead of three does the noise change if you turn the plug over?


#4

Ted and wglenn thanks for the quick feedback.

I tried different USB cord and static noise is almost gone! Strange, I used most quality cord and didn’t think it might be an issues. Looks like it is out of specs or damaged.

I still can hear some minor static from tweeters when I put my ear close to it. Which is not audible from my listening place.I will keep it watching for now. Also, I will try to use two pronged power plug (need to find adapter) and see it is will make more difference. BTW is it usual to have some minor static on twitters?

Thanks you! Denis.


#5

Since he tried laptops on battery power, wouldn’t that rule out 60 Hz (or 50 Hz) hum/ground loop?


#6

Probably, but it depends on what else might be plugged into the laptop, for example a powered USB hub or any externally powered device…


#7

If you have a cheesy USB cable that you don’t mind messing with you could strip the outer conductors (far left and far right) off of the PC end plug. They are Gnd and +5v, which the DS has no use for. This would knock out one source of ground loop.


#8

After one hour of listening, loud static noise is back frown. Looks like it is not USB cord.
I’m going to try two pronged power plug and unwiring ground/signal in USB.


#9

Is yours a PWD I or PWD II? You sound like you have reloaded the PSA drivers for windows at least once. You might try freshly downloading the latest PWD firmware (2.4.6 for PWD II) to the card and refreshing that as well. If you are already running 2.4.6, first put an older version on your card and boot that, then repeat with 2.4.6 so that it will newly load for you.

Have you checked to see if any other servers or drivers are activated on your PC that might be interfering?


#10

wglenn,

Since I have the noise from 3 different laptops when they powered from battery with no other active items connected makes me thing it is not the ground/signal or interfering programs issue. But, I will try to play around USB cable anyway.

Also, this is PWD II. I didn’t have PWD I. Latest drivers loaded for windows originally. Also and tried to reload older firmware and latest after that.


#11

Is this a newly acquired PWD II or have you run this unit successfully for a while prior to trouble? Did the trouble start with a particular software upgrade or addition to the PC or DAC?


#12

I’ve got PWD II from AudioGon. I returned item to seller and got new DS. No noise issue with new DS! Btw part of the reason I decided to go with DS if very responsive and helpful community here.

Thanks!
Denis.