Well I'm gonna assume your using audacity as its what most people seem to use (and it defaults to 128kbps).
Unless you change the uncompressed file format in audacity it records to WAV, 16 bit PCM which should be fine for recording a mix or a sample.
It only gets converted to mp3 when you tell it to export to mp3 - until then it is still in the raw format.
To change the quality Audacity records in you go to Edit -> Preferences -> Quality, but the defaults should be more than ample for most applications.
To change the bit rate (quality) of a recording when you export to mp3 you go to Edit -> Preferences -> File Formats and its near the bottom. This is the bit rate of audio exported to mp3.
Hope this helps clear things up.