The music you hear is nothing more than a .mp3 file which you can delete or alter. Here is the path to your victory music if you choose to change it...
C:\Program Files\Steam\steamapps\your name\day of defeat source\dod\sound\ambient
At this point you may need to create an ambient folder if there isn't one already. Once you have created an ambient folder within your sound folder simply drag your .mp3 files into it overwriting any existing files.
You'll need to title the files as such...
us_win.mp3...&...german_win.mp3
Attached are a shortened version of the Victory sounds...much shorter!
...MOSH MOSH!