Have Ameritron AL82 amp, No Tubes Have extra Eimac 4-400 tubes Looked at some amp's schematics for 4-400 and appears these would work in AL82 Have fired up filaments in AL82 (no HV) Any one tried this or have go/no go thoughts? 73 W5AJ Robert Midland, Texas http://pages.suddenlink.net/w5aj/