Remote-Cutoff Pentode
The 58 Vacuum tube is a glass type used in the RF and IF
stages of radio receivers
employing AVC and as a mixer in superhetrodyne circuits.
The 58 is a triple-grid super-control amplifier tube recommended especially for service in the
radio-frequency and intermediate-frequency stages of a-c receivers designed for its characteristics.
The 58 is characterized by the small overall size, the dome-top bulb, and the fifth electrode or
suppressor with its own base pin terminal. Equally significant among its electrical features are the
relatively low heater power consumption, the extended mutual conductance operating range, and the
adaptability of electrode combinations to various circuit applications. The ability of this tube to
handle usual signal voltages without cross-modulation and modulation-distortion makes it uniquely
adaptable to the r-f and i-f stages of receivers employing automatic volume control. Shield
construction and bulb shape are discussed under Type 57, which is similar in structural
appearance.
When the suppressor is not connected directly to the cathode, its utility may be extended. The
suppressor, in suitable circuits, provides a means for obtaining the desirable conditions of reduced
selectivity for local reception. This operational characteristic makes possible improved loudspeaker
response when the receiver is tuned to powerful nearby stations. It requires a six-contact socket.
Electrical Data:
Heater Voltage ................................ 2.5 V
Heater Current ................................ 1.0 A