This is a question that we are asked often and the answer is no. Yes there is a glowing vacuum tube in your 500 series module but it is a 9A type preamp tube. This is the same type used in the AKG C-12, Telefunken 251, etc. While these mics only have one section of the tube active, they also have less internal volume for the tube to cool and yet the surface temp of these mics never exceed room temperature. As long as you don’t block the venting that is already part of the 500 series power supply you will be just fine.