[Texasrocker]

It is always a good idea to have a trusty ol GE Tube Manual to reference all the electrical characteristics when in question of "subbing" tubes. Even the best quality tube-testers have been known to "lie" to me before. The best test for any tube is in the circuit,( according to proper tube placement via schematic or tube layout chart),... unless the filament is open, and/or the wrong tube has been inserted by previous hacker. Also, on any loctal-type alum base tubes, it is imperative to make sure ALL the tube-pins are all clean and shiny before placing them in a tester or circuit chassis socket to be tested. Those type tube designs werent the best from the get-go. Corrosion o'plenty developed!! Sometimes, all it takes for a "test bad" tube to be qualified as a "test- good tube", is simply by careful cleaning of the tube pins, and resoldering/ reheating the tubes pins-tips! I have found many loose/or corroded pin connections in the past, and saved me from ordering un-necessary tube replacements just by taking time to do a good mechanical-inspection of the tubes that tested bad. The GE Tube Manual tells the truth on "subs".