I am new member Alex Milne. I have been involved in amateur theatre for close to 60 years. Recently I was chosen to volunteer as the lighting designer for a small group here in Ottawa, Canada Last week we acquired some Colortran ellipsoids model no. 213-075. I came upon your site when looking for information on these units and found a very interesting thread right on my subject. I am going to follow up on the various suggestions made as I am also interested in how to change the beam angle on these units. When received they were equipped with 1K bulbs. In order to meet the output of our dimmer packs I would like to rebulb them with 575W bulbs. Any experience or comments on that?