It is a tube failure, but the original JA-80, which I owned, was VERY hard on tubes because of the high bias current. The original MO Valve KT-88 could last several years, but other tubes would not. The secret is to lower the bias by increasing the value of the cathode resistor (the output stage is cathode biased, not fixed bias).
Anyone had and trouble with Jadis JP 80 amps
I was demoing a pair of JA.80s with KT-88s and on 2 occasions a tube fuse blew. Just wondered if people are having any reliability peoblems or is this just an isolated occurance??