Originally Posted by
nickbaba
Having read/heard good things about the (very expensive) KR KT88 valves, I decided to try a set of 4 in my recently restored Radford TT100.
With great anticipation I installed them in the amp and switched it on, ready to re-bias it and get everything in order. But before I could even do that the valves started loudly fizzing, popping and randomly banging through my speakers, to the point that I had to immediately switch the amp off for fear of causing damage to something.
Thinking one of the valves must have been faulty, and not having a valve tester here, I returned the valves. But when they were tested by the dealer (in an amp and by a valve tester) they were found to be 100% fine with no issues.
Is there some reason why the valves would have been unhappy in my amp? Wrong current level or something? I assumed all KT88s are compatible across all amps that are made for them? Or could something else have caused the audio nasties, without the valves being at fault?