Name:    Steve Kennedy
Email:   steve@pacair.com  
Subject: Overheating tubes
Thread:  60
Time:    Wed, 25 Apr 2001 03:03:26 GMT

I noticed you didn't claim that the tube plates were glowing red or anything like that!


You might have a power supply problem, a bias problem, or you are using the wrong output tubes!


The older Music Man amps were designed to use a 6CA7 (American) tube, but a good quality EL34 will work as well. DO NOT use any Chinese EL34 tubes if you can help it. THe word is that they simply cannot take the high (700Vdc) plate voltage found in a Music Man amp on High Power setting.


Also, what setting is the speaker impedance switch, and what speakers are you connected to? Have you taken the amp chassis out of the cabinet to see if there is any sign of damaged or burnt components internally?


Steve