The EEP1 is a secondary emission tetrode for use as a wideband amplifier and/or phase inverter. The data-sheet shows the use as a phase inverter in a push-pull audio amplifier.
Secondary emission was used as a way of increasing the mutual conductance to allow for wider bandwidth amplification. The EE50 was designed in the late 1930s for television use and was quickly overtaken by the conventional pentode the EF50. Later the EFP60 was designed for use in computer divider circuits (counters) at up to 50 MHz.
The plain red screening paint with Made in Holland printed on it.
Looking into the top of the envelope reveals little.
The Ct8 base.
The classic envelope is 46 mm in diameter and, excluding the Ct8 base pins, is 117 mm tall.
References: Data-sheet. Type EEP1 was first introduced in 1947. See also1947 adverts.
