Radiophile.com - Knight 6C-225

Knight 6C-225, 1947

Tube complement: 14A7 RF, 14Q7 mixer/oscillator, 14A7 IF, 14B6 detector, 35A5 audio output, 35Y4 rectifier.

This radio has the deluxe type of AC/DC circuit, with an added RF stage for extra signal-pulling power. Unusual for an AC/DC set, it has a tone control, although it's just a two-position switch with the choices being tinny-and-strident, or muffled.

Approximately 12 inches / 30 cm wide. In the words of the discriminating collector from whom I acquired this beauty, it has "trim details, plump shoulders and an ample stern." I couldn't have said it better.

This radio uses those icky loktal tubes. Loktal tubes were introduced in 1938 by Sylvania. They were developed primarily (I presume) for mobile or vibration-prone applications. They're called loktal because they "lock in" to the socket with a positive click, and are held in place by a spring clip in the socket. Viewed with 20-20 hindsight, they were not a good idea. They're difficult to unplug from their sockets, their pins are small and offer little contact area, and the electrical pin connections are often intermittent—something about the pin material or plating seems to invite corrosion.