1022 如果是白色粉字,则不是管子型号,Mullard 的EIA Factory Code(国际化工厂编码),这个编码统一了全世界的生产厂家,也包括电容、变压器等产品。EIA编码表是有资料可查的,例如:
111 = Amperex
158, 171 = DuMont
188 = GE / KEN-RAD (188-4, 188-5, 188-20, etc.) [info]
210 = CBS Hytron [info]
247 = National Union [info]
274 = RCA [info]
280 = Raytheon [info]
312 = Sylvania [info]
322 = Tung-Sol (USA)
323 = United Electronics
336 = Western Electric
337 = Westinghouse
722 = Sylvania-manufactured for OEM equipment makers (Allen Organ…)
1022 = Fisher branded Mullard/Telefunken/Amperex
1109 = Raytheon (Japan)
U.S.A.3 (found on the glass envelope) = Tung-Sol
Xf1,Xf2,Xf3,Xf4 = Mullard
7C,8I = Toshiba (Tokyo Shibaura Electric)
早期Mullard四位型号暗码是用酸腐蚀公益印在玻璃上的暗色字迹,很难擦除,这时还未采用统一的philips编码,是英国BVA的编码格式,GEC/Brimar/STC都采用过此编码。 网上未见全面的资料。