(!!!!!) (Best Single #3) ECC83=12AX7 Telefunken Germany ribbed plates used/tests like new 1953-1955 (1.3/1.1ma and Gm=1700/1600) 1-5% section balance1 low noise tube) ECC83=12AX7 Telefunken Germany ribbed plates used tests like new 1953 1955 (pd) fairly good printing in white box 1 section) 1. 3ma Gm=1700 1 section) 1. 1ma Gm=1600 Good NOS Ma = 1. 0ma+ Good NOS Gm = 1500 1600+ Recommended for: Se Electronics Z5600a II Tube Condenser mic Veloce Audio Line Stage and Phono Amp Nagra PL L preamp VTL 7. 5 preamp MFA preamp Orange amps Conrad Johnson Premier 15 phono preamp Pilot SP 210 preamp Jadis