On 04/01/18 04:28, AJ wrote: > This time I was able to measure where it blew apart, ~20 uh from end to > end. I slid the wire off the broken ceramic and slid it onto a new one > mounted it in the amp to measure. I am referring to RFC-1 Well, 20uH in series with the tubes output capacitance is resonant on about 6-8 MHz. That might be worth exploring.. S