Tube manufacturers by alphabetical order:
ABB ADZAM AEG AMPEREX BELVU CETRON CHATAM CHINESE CIFTE ECG EI EIMAC ELORG FIVRE GE GEC HALTRON JJ K&R KENRAD LANDSDALE LMT LORENZ MARSHALL MAZDA MINIWATT MISC MULLARD NATIONAL UNION NEC OREGA PHILIPS RADIO TECHNIQUE RAYTHEON RCA RFT RTC RUSSIAN RWN SB SIEMENS SLOVAKIA SOVTEK STC SVETLANA SYLVANIA TELEFUNKEN TELAM TESLA THOMSON TOSHIBA TRONAL TUNGSRAM ULTRON UNITED ELECTRIC VALVO VISSEAUX WE WESTINGHOUSE ZAERIX
