I have had the Adcom and currently have the Placette with Merlin speakers. The Placette was significantly better in every way. On my system the Adcom sounded brittle and bright while the Placette, still slightly on the dry side, toned down the highs, solidified the imaging and had a more coherent presentation. I would recommend the Placette over the Adcom. I cant comment on the other passive preamps.
