(!!) (Pair) 6SF5 RCA metal can NOS 1948-1957 (1.2ma and 1.0ma)

1 matched pair) 6SF5 RCA metal can NOS

1 tube) 1.2ma Gm=1400 RCA Victor 1948

1 tube) 1.0ma Gm=1600 RCA 1957

Good Ma = .9 - 1.0ma

Good Gm = 1400-1500

(6SF5=6F5 without top cap and 7B4)
(6SF5GT are used in Fi X 2A3/45 SET amp)
(6SF5GT have gain similar to a 12AX7)
(Vplate=240V, Vgrid=-1V, Mu=110, Gm=2120, Rplate=52Kohms, Pout=.48 watts)

- Masco MA-808
- Supro amp
- Fi 2A3