I have heard that at some time, while still manufacturing 811A tubes, RCA changed the manufacturing process of the 811A tubes to reduce the cost of making them. What time frame was this if it is true? Bill ===== Bill Smith KO4NR -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: owner-amps@contesting.com