[electricroo]

The transistor can handle up to 100ma without a heatsink. So the radio should draw arond 70ma at m9st. I was concerned about temperature due to the warm tube chassis because there was not enough room to add a heatsink in the location. After operating for 2 hours I checked the temperature on the tab with my temperature probe and it was 60c. According the TIP50 data sheet maximum temperature is 150c. Though I have used the circuit in two amplifiers that I built as output tube screen voltage regulators, I had room to include heatsinks on the transistor.