12DF7
Branded Westinghouse

Pinched Tip

Notes: - Very rare engineering samples of these, also very rare aircraft/hospital grade versions of the 12AX7! Seldom seen, but well worth the search, they are super quiet and extremely detailed. These have square top getters and grey plates, with the old yellow Westinghouse label of the early 1960s, and marked Engineering Sample, so these are factory hand selected first production runs! > Brent Jesse (link: http://www.audiotubes.com/12ax7.htm text: audiotubes.com), - Very rare engineering samples of these, also very rare aircraft/hospital grade versions of the 12AX7! Seldom seen, but well worth the search, they are super quiet and extremely detailed. These have square top getters and grey plates, with the old yellow Westinghouse label of the early 1960s, and marked Engineering Sample, so these are factory hand selected first production runs! > Brent Jesse (link: http://www.audiotubes.com/12ax7.htm text: audiotubes.com)