TR1037

"Fetron", solid state replacement for 407A tube, manufactured by Teledyne.

The "Fetron family" was designed for replace vacuum tubes in telephone communications equipments (carrier, multiplexer, demultiplexer etc.) or lab equipments (for example
HP 400 VTVM conversion kit, Tektronix CA plugin conversion kit).

A "Fetron" is not a universal replacement for vacuum tubesand must be configured differently for certain applications.
For example, the "Fetron" configuration will generally be different for a pentode amplifier and an oscillator.

The "Fetron" is composed of one or more high voltage JFETs, a protective fuse, and R/C networks for tailoring to the required circuit
performance parameters.