The STC 5A/152M is a telephone repeater pentode. The maximum anode dissipation is 5 W and it is designed to operate as a low power low distortion amplifier. Typically producing 50 mW output at less than 5% distortion. The load required is 6 kΩ.
The STC logo printed onto the glass.
The internal details are shielded from view.
The wide glass tube envelope is 28 mm in diameter and, excluding the B8B base pins, is 64 mm tall.
