Note
QST, Dec 1950, p. 4.
An AC/DC version of the S-40B. The S-77 can operate on 120-240 volts AC or DC depending on ballast resistor R39.
Features include a headphone jack, BFO, ANL, AVC, pitch, mute, built-in speaker, three position tone control, and sensitivity control, and a zero to 100 bandspread.
The S-77A is outwardly identical to the S-77, but may include some minor component changes.
Coverage: 540 kHz to 44 MHz
IF: 455 kHz
Modes: AM, CW
BFO
ANL
AVC
Uncalibrated Bandspread
Audio output: 1 watt, 3.2Ω
Power (S-40B): 120 VAC, 75 watts
Power (S-77): 120 volts AC-DC
Tubes: (8 total): (1) 25Z6, (1) 25L6, (1) 6SC7, (1) 6H6, (2) 6SK7, (1) 6SA7, (1) 6SG7
