Dogpile,
Excellent suggestion re: the spacer. The TP website even shows them, in black or silver to match the arm. Anyone whose armboard puts the VTA tower in the top half of its range should try one.
André,
Good description of the sound. That helps, and you just gave us three more good clues:
1) the tremolo occurs only at the beginning of sides,
2) the tremolo did not occur or was not audible with an A-N IQ-3,
3) the tremolo does not occur on 200g Decca reissues,
I have a hypothesis which explains #1 and #2. If it's correct then you should hear the tremolo with your friend's DL-103. (Make sure you set VTF to 2.2g or above, as the Denon prefers.) Let us know your results.
If my hypothesis is correct there are ways to solve the problem.
Unfortunately #3 seems to contradict my hypothesis. Do you have a 200g Decca with strong piano attacks at the very beginning of a side? If so, play that with the Shelter 901 and try to cue the stylus as close to the first music groove as possible. (I'm trying to disprove #3!) :-(
Doug