Recording is distorted

I recently acquired an all-in-one turntable, radio, cassette player and CD player. My intent is to use the turntable and cassette player to make CD’s of some old recordings friends and family either can’t find on CD or don’t want to re-buy.

Let me start by mentioning that I’m a Linux user. I’m using an onboard soundcard with a VIA chipset. Right now, I’m trying to record from the radio so I can fine tune my recording settings. When I try to record with Audacity, I get a high pitched ring in the background, and the audio is fairly distorted.

I know the signal is fine for two reasons. When I unmute the line in without recording, the audio is crystal clear. I also have MythTV on my system, which is used for recording TV shows. When I tell MythTV to use that signal for the audio, it sounds fine (but has miscellaneous TV video associated with it).

What settings can I change to get Audacity to record properly?