(!!) JRC-12AU7 RCA NOS long gray plates mid-1950's "D" getter (9/11.6ma)
(!!) JTL-5687WA Tungsol bronze plates "O" getter used/good 1958 (30/30.5ma)
(!!) Recommended Pair) 6CW4 RCA NOS 1963-1974 (90/60 and 96/60)
(!!!) (PAIR) UX-201-A Radiotron Balloon used/good brass pins 1930's (2.3ma and Gm=700 x 2 tubes)
(!!) UX-201-A Radiotron Balloon used/good brass pins 1930's (2.6ma and Gm=700)
(!!) (Best Single) UX-201-A Radiotron Balloon used/tests like new brass pins 1930 era (4.4ma and Gm=800)
(!!) UX-226 Radiotron Balloon used/65% (3.8ma, Gm=900)
(!!) UX-226 RCA Balloon NOS 1930 era (7.6ma, Gm=1000) (very nice single)
(!!) UY-227 RCA Radiotron Balloon used/good 1930 era (3.5ma)
(!!) UY-227 RCA Radiotron Balloon used/good 1930 era (3.7ma)
(!!) UY-227 RCA Radiotron Balloon used/good 1930 era (3.8ma)
(!!) UY-227 RCA Radiotron Balloon used/good 1930 era (4.0ma)
(!!) (Best Value Pair) X-226 and MX-226 no name balloon used/like new 1920's same build (6.3mA and 6.5ma)
(!) (#1 12AT7 Value) 12AT7 Sylvania branded Philips black plates NOS 1970's (7.6/8.2ma)
(!!!) (slightly microphonic single) ECC801S Telefunken <> bottom rebranded 12AT7/ECC81 Telefunken NOS 1962 (9.2ma/10.2ma)
(!) (Best Value Single) ECC82=12AU7 Zaerix East Germany NOS 1970's (12.8/12.0ma) (same Gm)
(!!!) (Smooth Single) ECC82=12AU7 Ediswan Valve by Brimar England NOS ribbed plates large "O" getter halo 1962 (11.4/11.8ma)
(!!!) (Best Value Single) ECC82=12AU7 Philips Miniwatt Holland ribbed plates used/like new 1963 (9.4/9.8ma)
(!!!) (Best pair #3) 12AU7A GE NOS 1958-1965 (10/10.6 and 10/11.6ma) (close Gm)
(!!!!) (Recommended Pair) 12AX7 Philips and Valvo Holland NOS 1965-1966 era (1.2/1.1ma and 1.3/1.2ma)
