Thanks for the responses guys. I have a compu-bias meter. I didn't change the bias at all from where it was which by the way was on the low side of what the manual recommends. There is no recommendation to reduce bias before tube installation anywhere in the manual. The amp comes from the factory already biased. And yes I did swap sockets and confirm that it was the tube and not a blown resistor. I got a call back yesterday from one of the other ARC guys and he had me send an email to their service department. Th tube was definitely DOA as you can easily see the slow turn on and ramp of the bias current and output power with the comps-bias meter. It didn't arc, pop or any other telltale of failing on installation.
I've been wondering about the use of the KT120s. Thanks for the info BIF. I will definitely inquire with the service guy when we communicate. My local ARC dealer actually suggested the same thing last year. What kind of difference did you hear?
I've been wondering about the use of the KT120s. Thanks for the info BIF. I will definitely inquire with the service guy when we communicate. My local ARC dealer actually suggested the same thing last year. What kind of difference did you hear?