Noise from USB DAC

[Amos]

Hi everyone

My setup is PC-> ODAC (JDS Labs)-> Digital amp

When I connect the DAC to my laptop it works fine, but when I connect it to the PC, there is a kind of white-noise and the sound quality is significantly lower. The same noise continues even when I unplug the power cord from PC, so I don't think that it's a ground-loop issue.

1. Does anyone have an idea what can be the root cause of this issue?

2. Can a high-quality PCI USB card prevent suce noise?

Your assistance is appreciated.

Amos

[Nikhil]

There is a lot of noise in the 5V "wire" of the USB cable mostly from the noisy computer power supply. I would recommend using a dual headed USB cable which separates the data leg from the power leg - has made a significant improvement in sound for me.

[One and a half]

To the OP, what else is plugged into the PC apart from mouse, keyboard and Ethernet cable?