Philips
model 2637, 1931
More photos and detailed specification
This radio was one of the first Philips to be equipped with an integral
loudspeaker.
The main tuning control
tunes the grid of the RF amplifier, the anode is tuned by adjusting the second
(tracking) tuning control for optimum response. The gain is adjusted by
manipulating the reactive detector and volume (bias) controls.