I have a long time friend and avid audiophile who has a Heathkit TT-1. He no longer runs tubes, and is willing to sell it to me. Unfortunately, he's not sure if it tests the larger tubes like the 300B. This is kind of a make or break with me, because my monos have a pair of 300B's each. Does anyone know if the TT-1 does, or if not, I'm also open minded to other Tube Testers.