I also noticed that in the trash compactor sequence, the complete music background was removed on the 2004 SE from the point on where they hear the roar until the point Luke is released by the monster. It is also present on the German dub. Some other guy told me that the 1993 definite edition LAserdiscs also don´t have this background music.
All German releases excluding the 2004 editions seem to match the original mono mix. That´s why i was really puzzled, when i heard the english audio on the 2004 SE that some sound effects were radically different.