Background Noice problem with US 366

[EESYEES]

Hi guys,
i am glad to have found this forum and hope anybody can help me.
I have a TASCAM US 366 interface which i am quite happy with - BUT one thing that is literally killing my ears is the fact that when nothing is playing on my system - i hear a low digital electrical noise through my speakers.
I have done all sort of tests to check weather its the cabels that might get electrical interference, and it always comes down to the interface - as soon as i unplug the 2 Jack cables going to my amp the digital background noise is gone.
what can i do to get rid of that noise - its soo irritaiting.
Thank you in advance

 

[Gravity Jim]

What power source is your interface plugged into? The wall? A UPS? Power strip?

 

[EESYEES]

the power source is the USB cable that is plugged into the PC, and the PC gets fed by a normal wall plug.

 

[Gravity Jim]

Have you tried a different USB cable? Can you try powering the unit from the wall, or is that not an option?

 

[EESYEES]

Yes i have tried a different 8even shielded) USB cable and also a different USB port - still the digital background noise is clearly heard.
Unfortunatly the US 366 can only be powered with a USB cable - no other options avaialble.

 

[Gravity Jim]

Your PCs USB port may be supplying too little or unsuitable power... Not all ports are created equal. My wife used to run a radio station that read current print material to the blind or otherwise print-impaired, and was trying to get the Blue ICE USB interface working with mics for use by home-based readers. Two returns later we realized the USB ports on the station's Dell desktops didn't send enough juice to get the interface to operate.

Of course, the unit itself might be defective, but the only time I ever heard noise like you describe from an interface, the problem was the quality of the juice (an uninterruptible power supply that output power in a square wave generated non-stop background hash in a MOTU 2408... A better UPS that output a sine wave fixed it).

You can: a) plug the unit into the wall with a USB adapter, b) buy or borrow a high-quality PCIe USB expander for testing, or c) exchange the unit and start troubleshooting the juice if the new one fails in the same way.

 

[EESYEES]

THANK YOU SOOO MUCH for the in detailed HELP!
I will try exactly these things and will let you know what the problem was.
but my guess is also its the USB port that might cause this - i have this TASCAM US366 for quite some time now - and did not have the problem on other PCs!
lets see, thankx again for the help
really appreciate

 

[Gravity Jim]

You're welcome. Your post pretty much confirms the problem for me... That USB port is likely sending too little power for an interface.