Looks like it's anybody's guess. The article I read pointed to, and had pics of, an M-102, but that was for the original cut at Olympic Studios. The article in Cowboy's link above mentions, and has pics of, a C3, and the Procol Harum official website talks about a B3. So, it looks like maybe they used whatever was handy, as long as it was a Hammond. That goes along with the article I read, which stated that they originally wanted a "Hammond" sound. Ray, I think for you, the most important things are the drawbar settings in that link from Cowboy, but the official website has another hint. Whenever possible, Matt kept his Leslie isolated offstage in a separate room or closet, and miked it to the sound board from there to keep its sound pristine and free from other stage sounds. So far, though, I have not seen any mention of external effects processing. Odd ! I'm like Gary. I would have thought there would be, at least, a little something, but then, would a guy who locks his Leslie away in a closet allow a sound guy to mess with his sound ?