i did some measuring today using my wavetek meterman 35XP DMM with thermo couple attachment. I measured the temperature at various places every 5 minutes for 30 minutes. My findings, measurements to follow, are that the amp circuit does not get very hot, most of the worst heat happens in the first ten minutes, maybe with the exception of the cathode resistor and PT which will continue to get hotter. Most of the circuit stays below 80 or at least below 90 degrees F. The rectifier tube pins show the most heat and then the power tube. This is a champ amp. The power tube glass gets hotter than the rectifier tube and the cathode resistor stays hotter than the power resistors. The hottest place on the amp circuit is pin 8 of the rectifier tube. In 5 minutes it is 144 F and basically stays there. Pin 2 of the rectifier is lower, reaching 100 F after one half hour. All of the power tube pins, 2,3,4,5,8 gradually rise up to 100 F. Pin 8 gets the hottest, 130 F after a half hour. Pre amp pins stay below 90. The pilot light and power switch stay below 80 F. The glass goes up to 150-170 F. One odd result, the chassis by the PT did not get warm as fast as the opposite end of the chassis, by about 5 degrees. The OT peaked out at 80 F after 30 minutes, with no signal. I will try later with signal, see how hot things get after 1 hour, maybe 2 hours as well.