hum with line in on sound card

[cavingjan]

I have a hauptpage wintv usb plugged into my computer (I love this thing for the price I paid for it) with the sound running into the line in. I hear a hum coming across that line in channel. It was like this with my old SB PCI64 and also the Fortissimo II that I just installed the other night. Any suggestions? The tvtuner gets its power from a usbhub which is plugged into the same outlet as the computer so the old "make sure everything is on the same outlet" idea goes right out the door. Normally I just mute that channel until I want to use the tvtuner. The hum is not loud enough to be heard over the audio from the card but when there is no other audio coming from the speakers (with the line-in volume turned up).
Any suggestions?

 

[Workin']

Try using a groundbuster on the power supply for the USB hub. Even though they are plugged into the same outlet they are still separate chassis, so a ground loop is still possible.

If that doesn't work then check that no connections are loose (well, do that regardless), and then consider that some part is defective and generating the hum.

 

[cavingjan]

I just happened to ponder whether this is caused by the cable (tv cable). I'll have to try to disconnect the cable from the tuner and see if I still get the hum.

Edit: I don't think its that because I had the hum when it was plugged directly into a usb port off of the computer. But just to confirm that, I can try moving it back over to the last of the computer usb ports. I have way too many USB devices.