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The EF183 is a high gain variable μ RF amplifier pentode. It is a late 1950s design and superseded the EF85. The EF184 was the straight version of the design and replaced the EF80. All four valves have the same pin connections.

The EF183: a frame-grid variable-mu RF pentode for use as an automatic gain controlled IF amplifier in television receivers. The heater is suitable for series or parallel operation by AC or DC.

The valve performance figures are given at 40 MHz and the normal TV IF frequency was around 33 MHz.

The standard layout of screen grid, suppressor grid and two small joined anode plates is familiar. The frame grid in the centre is not seen but the very fine wire used on the frame is wound at around 50% of the breaking strain to ensure a flat path across the supports. This flat face allows the grid to be positioned very close to the polished surface of the flat cathode. The closer the cathode/grid spacing the higher the mutual conductance possible.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 54 mm tall.

References: Data-sheet & ¹⁰⁴⁰. Type EF183 was first introduced in 1959. See also 1959 adverts.

Pin Connections

Absolute Maximum Operating Conditions^¶

Thanks to Frank Philipse for supplying the above PDF datasheet.