My cat knocked over the magnetic fan that cools my 500-C's four 7591A power tubes. Just for kicks I decided to measure their temperature when not cooled. I use a laser gun. I was shocked that one of them measured 125*C. That's well over boiling. I've got the tubes biased at 34mA. Is my concern warranted at this temperature? What is considered a safe range at which the tubes operate? Is there a circuit adjustment I need to make to lower the temperature? Thorne PS - I remember this topic was discussed many months ago, but a search didn't turn up the thread.