Well, I took the big step and upgraded my computer. This meaning I also upgraded the sound.
So, I got the Audiophile USB from M audio. It features its own seperate PSU, but somehow noise seems to find its way thrugh the USB connection anyway. Strange thing is, the noise go away then I start playing or do any activity on the computer.
The noise is a continous buzz at a couple of KHz's.
The big question is, can I get a filter that cleans the USB signal. I can make one myself if someone got a schematic for it?
So, I got the Audiophile USB from M audio. It features its own seperate PSU, but somehow noise seems to find its way thrugh the USB connection anyway. Strange thing is, the noise go away then I start playing or do any activity on the computer.
The noise is a continous buzz at a couple of KHz's.
The big question is, can I get a filter that cleans the USB signal. I can make one myself if someone got a schematic for it?
I tried measuring with digiscope the voltage at computer case. If i use peak detect (in Tektronics TDS 210), i see 150 mV peaks at about 8 ms intervals, probably coming from switching power supply. This causes some audible background noise.
I used 10 ohm resistor in my USB DAC to get some isolation between digital and analog ground. This made the noise inaudible. I guess you could try some kind of inductor in series in GND and +5V USB lines. This might cause problems with USB communication...
http://hepso.dna.fi/misc/pcm2902/PCM2902_usb_dac.html
I used 10 ohm resistor in my USB DAC to get some isolation between digital and analog ground. This made the noise inaudible. I guess you could try some kind of inductor in series in GND and +5V USB lines. This might cause problems with USB communication...
http://hepso.dna.fi/misc/pcm2902/PCM2902_usb_dac.html
Are you sure its not just a simple ground loop?
I would think the "Audiophile USB" would have some kind of USB ground isolation built in.
If it doesnt, you would have to be a little dissapointed.
Do you hear the noise in headphones plugged into it?
I would think the "Audiophile USB" would have some kind of USB ground isolation built in.
If it doesnt, you would have to be a little dissapointed.
Do you hear the noise in headphones plugged into it?
MWP said:
Ground loop you say?
The noise was'nt in the headphones, so the problem must be in the amp, then. I removed the cable from the cheap integrated soundcard to the amp and this solved the noise problem. Just like that!
I don't realy need that cable anymore now the 'audiophile usb' is playing beautifull music. Thanks. 😎
UKRAM:
Nice project you have there. Now I solved the problem, there is realy no need to build a filter right now. But, I will try out a few posiblities anyway. It certanly won't hurt the soundquality to try. Maby I could isolate the usb line from the computer totaly, using optocouplers for the data transmision and make a whole new clean 5 v supply and only use the 'real' usb 5v to sense the connection?
Same problem with USB port
I have the same problem with my USB port. I say I have the same problem because I used two different external sound cards made for high end music production and I get the same cycling buzz sound. In my case I can hear it in the headphones and thru the speakers. Funny and extremely annoying now is that when I plug both to my laptop they are both buzz free. I mean very quiet!! This is driving me crazy. So I am attributing the noise to the USB ports. There might be a ground loop issue. I don't know. How to find out? Last year I built myslef this high end desktop computer to work with my home recording studio and this is just a "buzz" kill. Pardon the pun! Can anyone point me in the right direction? Cables are not helping. I bought some very expensive intsrument cable ($50 a pair) nope it did not work. The sound cards in question are the Roland VS-20 and the M-Audio Fast Track Pro. Any help would be very much appreciated. 😡 The last thing I did wierd was wrapping at the ends with aluminum foil and got a USB hub that plugs directly to the motherboard USB port with no power supply. It helped a little bit put the sound is still there. Thanks for any help you all can bring.
I have the same problem with my USB port. I say I have the same problem because I used two different external sound cards made for high end music production and I get the same cycling buzz sound. In my case I can hear it in the headphones and thru the speakers. Funny and extremely annoying now is that when I plug both to my laptop they are both buzz free. I mean very quiet!! This is driving me crazy. So I am attributing the noise to the USB ports. There might be a ground loop issue. I don't know. How to find out? Last year I built myslef this high end desktop computer to work with my home recording studio and this is just a "buzz" kill. Pardon the pun! Can anyone point me in the right direction? Cables are not helping. I bought some very expensive intsrument cable ($50 a pair) nope it did not work. The sound cards in question are the Roland VS-20 and the M-Audio Fast Track Pro. Any help would be very much appreciated. 😡 The last thing I did wierd was wrapping at the ends with aluminum foil and got a USB hub that plugs directly to the motherboard USB port with no power supply. It helped a little bit put the sound is still there. Thanks for any help you all can bring.
Get a ground isolator which uses the ADUM4160.
Hifimediy has one on fleabay that breaks the ground connection and provides up to 200mA in power...usually will be ok for any usb based converter.
Hifimediy has one on fleabay that breaks the ground connection and provides up to 200mA in power...usually will be ok for any usb based converter.
Thank you so much. I am not familiar with Fleabay. Can you give me more specifics? Is it fleabay.net? and should I search for ADUM4160 or Hifimediy?
Thank you so much for the help the noise is driving me crazy!!
Thank you so much for the help the noise is driving me crazy!!
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