Amiga 8 bit audio data have to go through pc audio hardware (soundcard, onboard). So the quality is similar to original. Amiga 16 bit audio data (AHI, ...?) should be as similar good as the pc audio hardware can provide.
There might be possibilities to change original 8bit audio data using pc audio filter on the fly but the quality won`t increase much. You know interpolation is interpolation (guessing).
Toni can tell you more.