I was using a rheostat to control the fan on my old heatsink(think it was a volcano 2 or some garbage like that), now I upgraded to a vantec aeroflow, the one with the TMD fan. The thing is, the rheostat gets extremely hot when slowing down the TMD fan, but didn't at all with my old volcano 2. It's getting so hot that it could honestly burn you. Should rheostats just not be used with a TMD fan?
TMD fan
TMD fan