What is the minimum voltage I need to provide my tube to be able to produce some sound? I am trying to debug my first tube amp, but I can only power it with a 11,8V supply instead of the recommended 13,3V.(PCL86)
Could it be that the triode and pentode doesn't open because of this? Or in an other way: What filament voltage do I need relative to the recommended one to be able to use a tube?