I think the crackling on Country Air is a problem with the organ or an amplifier and not the recording equipment.
I think it sounds cool...like I said, it reminds me of a single trumpet note being held.
This reminds me of the end of the Beatles' "Long Long Long", where Paul hits an
organ note that causes the Blue Nun wine bottle sitting on top of the organ to start
rattling...
I think it's a Mellotron or Chamberlain tape-loop error. If you listen to the Sagitarius track 'Musty Dusty' you hear that same sound. Perhaps Gary Usher hired the same equipment ? By the way, on 'Musty Dusty', is that Bruce singing ?