How to tell vacuum tube is gone bad??
I recently purchased primaluna prologue 3 and I connect with dynaudio bm6a.
First I saw is lights of three vacuum tubes are dim and
other lights of three vacuum tubes are bright.
Among 6, 1 of vacuum tube has little soot on wall.
When I connect output-2 with bm6a speaker (active speaker), the volume is very low even I tune max volume.
When I connect output-1 with the speaker, the volume is loud enough with 1/3 of preamp volume.
Are these symptom indicated bad vacuum tubes?
Any other way to check vacuum tube??