Can anyone tell me what the difference is between the 0A2 and 0A2WA? All the tube manuals I have just say "INDUSTRIAL TYPE" for the WA and 0A2, refering to the 0A2 for characteristics.(0A2 is not even listed in RC22) Mr. Sibley says WA is rated at 148V vice 150V for 0A2. Obviously the WA is built different but in what respect? I have always substituted the two. 73, Dick KF4NS Keep the glow!