Pionier S 503 A

The Pionier S 503 A is a mains-powered tube radio receiver made in Bucharest by Radio Popular, the factory that became Electronica in 1960 [1]. It was assembled from kits imported from the Soviet Union [1].

Pionier was one of the names of the 36 types of popular-class table radios made at Radio Popular [1]; the list also includes the later Pionier S 521 A2 and Pionier S 521 A3 [1].

The book uses a photograph of the S 503 A chassis to show how radios were built at the time: all connections were hand-wired point to point, with the leads and passive components running through the air between terminals [1].

In the source table, sensitivity is given for 50 mW output, selectivity at 1 MHz for ±10 kHz detuning, the audio frequency response at −6 dB relative to 400 Hz, and output power at 10% distortion [1].