I want to record certain radio shows on 2.4.2 while keeping the computer sound off. I used to be able to do this by connecting the headphone and microphone jacks on my old computer but my new computer only has 1 combo jack. To record a show, I either have to leave the sound up, which is irritating to people who don’t want to hear it, or plug in the headphones, which makes the sound inaudible but also records at a VERY faint level. Also when I do this the microphone records every ambient sound, such as my barking dogs. It seems there should be a way to record the stream without outputting it to the speakers or headphone and with the microphone muted.
Buy a stereo mini-jack plug - you can often pick one up for under $1 (or a cheap lead that has a stereo mini-jack plug).
When you need to record sounds playing on your computer, plug that in and it should fool the computer into thinking that your headphones are connected.
Also, turn down the volume for the microphone when recording so that the computer does not pick up hum / hiss from the mic input.
Erm… I may be completely missing the point here, but can’t you set your recording device to monitor your audio output?
You can do this on both Linux and Windows (Never done it on Mac OS) by recording ‘Stereo Output’ or ‘Stereo Output Monitor’, depending on what is in your audio drivers.
Then, you just switch off your speakers.
Alternatively, you could use a media player which can send stream output to separate MP3 files (or a single one if you want to do it that way) instead of playing it back through the sound card. It can run in the background whilst you use your PC and make sounds with other software.
Back in the day, I used to use “WinAmp” and “StreamRipper” - I would script it to change track (via CLAmp on WIndows) and return to hours of radio music split onto individual MP3 files lol I am not sure what would do it nowadays but you may be able to get hold of Winamp and the plugins.
James
I used Winamp for karaoke many years ago. I like that idea of an mp3 output plugin. 
Also, whenever you get an update from Windows, you never know if your drivers are going to be jerked around. I keep an old USB audio interface around just in case something goes belly up with my drivers. You could look at, for example, a Behringer U-Control UCA222 (on sale for $19) and a stereo rca phono patch cable.
Sometimes you can discover a hidden loopback device. Right-click on your speaker icon (Windows task bar, lower right-hand corner), then select Sounds > Recording. Right-click in the middle of that windows where you microphone is listed. Select Show Disabled/Disconnected Devices. Then if you see Stereo Mix, for example, suddenly appear, right-click on it and Enable it.
I hope this helps.