Description
(!!!!!) (Recommended Single) 421A Western Electric NOS 1969 (85ma and 75ma)
1 tube) 421A Western Electric NOS 1969 (6939)
1 section) 85ma Gm=15,900
1 section) 75ma Gm=14,900
Good Ma range 70-100ma
Good Gm range 14,000 – 16,000
BEST FOR:
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Peter Millett headphone amp
Woo Audio 2
Woo Audio 3
Woo Audio WA3+
Darkvoice 336i
Darkvoice 336SE
Fi 421A
Singepower Extreme
(5998 is an uprated 6AS7G and has a 13 watt plate dissipation rating)
(the 5998 sounds very clear and has superb overall sonics, the 421A Western Electric sounds even better; slightly more magical sound)
(5998 Mu = 5.4, Gm = 15500, Rplate = 350 ohms, Vplate max = 250 volts and Vplate max 5998A = 275V)
(7236 Mu = 4.8, Gm = 12500, Rplate = 350 ohms, Vplate max = 300 volts)
(7236 is a computer rated 5998A, 7236 and 5998A are uprated from 5998)
(6AS7G Mu = 2, Gm = 7000, Rplate = 280 ohms)
(6080 Mu = 2, Gm = 6500-7000, Rplate = 280-300 ohms)
5998 substitute = 7236
7236 is a computer rated 5998A
5998 RATINGS:
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Filament Voltage 6.3 V
Filament Current 2.4 A
Plate Voltage (max) 250 V
Plate Current (max) 125 mA
Plate Dissipation (max) per section 13 W
