General Electric F-40, 1937
Tube complement: 6A7G mixer/oscillator, 6B7G IF/detector/1st audio, 41 audio output, 80 rectifier.
Approximately 10 inches / 25 cm wide.
This radio squeezes a lot of performance out of a four-tube circuit design. The 6B7G is, first, a multifunction tube that is used as both the IF amplifier and the detector. But in a novel twist, the detected audio is fed back to the input of this stage, where it gets amplified right along with the IF signal. Since the two signals are on completely different frequencies (and the stage is reasonably linear) there is negligible interaction between them.
The radio's rear view, showing its beautiful Bakelite back (alliteratively speaking).