4x SameCode 3Mica 1961 GE USA 5751 GoldGrid /Top 12AX7 ECC83 Sub /E83CC ECC803
The high power 5751 is a premium 12ax7 ecc83 sub w/ less gain, introduced in 1949 as military spec and industrial grade. originally designed for aviation, the costly rugged 5751 design is less prone to microphonics, w/ higher power 175ma.