Vintage russian tube 6J4 (6Ж4) is an sharp-cutoff high transconductance pentode, intended for service as a wide-band video or radio frequency amplifier. It is also suitable for use as a mixer or oscillator. It is direct replacement for the american 6AC7 (1852) tube and also for the 6F10 from Tesla. Special versions of this tube are marked as 1511 and 6J4-V (6Ж4-B). You can also use it instead of the chinese 6J4P (which has another shape, bulb type). New in box tubes, made in the early 60's (please see the gallery). Tested on BM215A.