75A

Collins 75A Amateur Band Communications Receiver: Double conversion, AM/CW, six amateur bands from 80 - 10 meters (3,2-4,2 / 6,8-7,8 / 14-15 / 20,8-21,8 / 26-28 and 28-30 MHz), five step crystal filter 0.2 to 4 kHz.
Early 54A-1, the early sets came without limiter switch at the right above function knob.
Osterman states: "One view is that the 75A-1 was simply referred to as Collins 75A until the 75A-2 came out in 1950. Another theory suggests that a small run of < 200 75A's were made in 1946."
Moore has in his remarks: "Early 75A" and shows an image without limiter switch, in the remarks of the 75-A1 he states "Differs from 75A in limiter switch on right side above function knob"
Further clarification about this matter is still needed. Anyway first advertised in Electronics, December, 1946, page 256. No limiter switch visible in the image in the ad.

In questo link sono elencati 100 modelli, di cui 77 con immagini e 35 con schemi.
Elenco delle radio e altri apparecchi della Collins Radio Company; Cedar Rapids (IA)