1958 Echo TRK-225
Shirt pocket radio, thermoplastic cabinet
4 3/16 x 2 5/8 x 1 5/8 inches / 106 x 67 x 41 mm
Six transistors (Hitachi, HJ15,2x HJ17D, 2x HJ22D, HJ23D), one diode (NEC SD46)
One standard 9-volt battery
Manufactured by Kokyo Electron Ind. Co. Ltd., Japan
This example was produced in mid-1958, according to the electrolytics. It has oval Hitachi transistors and a snappy red plastic encapsulated tuning cap made by Kikuna Elec. Co. Information on the Echo's manufacturer, Kokyo Electron Ind. Co. Ltd. (see photo below), remains something of a mystery.
As I wrote on my M31 site some years ago: "The first of at least three versions, this is one of those radios I love for its being so glaringly "primitive": the speaker grill holes don't line up, the "ECHO" logo is hilariously uneven, the tuning dial cuts into the cabinet body... and it's an absolutely gorgeous radio! And so "geometric" -- circle, trapazoid, rectangle..."
And you know what? I still think so today!