1x NOS BlueTip EiYugo ECC83 12AX7 /w/ TelefunkenTooling /ClassicVintageAudioTube
Taper base edition featuring copper grid rods, which minimize cathode-current contamination, and dissipate heat better. full mutual conductance gm % test + life test pass (longetivity indicator) + an impeccable leak / short / gas check.