4x NEC Nippon (WE Japan) 3Mica TopD 5751 /Top 12AX7 ECC83 Sub /E83CC ECC803 7025

The high power 5751 = premium 12ax7 ecc83 w/ slightly less gain, introduced in 1949, as military spec + industrial grade. originally designed for aviation, the costly 5751 design is more rugged + less prone to microphonics, w/ higher power 175ma.

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