[shaler78]

I have the fan set up that it only runs when the radio is switched on, so it really doesn't run continuously. It does seem to keep everything much cooler. That 5Y3 does get as hot as an incandescent light bulb. One of the hottest running tubes that I've come across in any of my old radios. The foil backed insulation is a good idea, and something I didn't think about. I'm going to give it a try.