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Vintage Radio

Featuring no less than eight valves, the Lyric Model 70 broadcast-band receiver is an upmarket American-made set from the late 1920s. It's a tuned RF design with single-knob tuning and a number of interesting design techniques.

By Rodney Champness, VK3UG

Experimenters in the early days of radio produced some very ordinary looking receivers, mainly because they were forever changing things to improve the performance of their sets. Sometimes they were successful but mostly they just thought their set was definitely superior to their mate’s set.

Those early sets were built on wooden boards and these were commonly referred to as “breadboards”. In fact, some were built on a real breadboards, pirated from the kitchen!

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The unit features a 4-gang tuning capacitor, a large drum-type dial and a plug-in capacitor box.

The breadboard-style layout was a very convenient method of construction during the early days of radio, as it made it very easy to continually change a set’s circuit or layout. As a result, experimenters’ sets used this style of construction for many years and even today the term “breadboarding” is used when building makeshift circuits.

Breadboarding led directly to the so-called “coffin style” radios when companies began manufacturing domestic receivers in the early 1920s. In reality, these were breadboard sets with a nice wooden cabinet built around them, with a hinged lid on top that allowed ready access to the set’s internals. This also made it easy to occasionally tweak the circuit for better performance.

Receivers in the 1920s were attractive pieces of lounge-room furniture and that certainly applied to many coffin-style receivers. However, as the 1920s progressed, most manufacturers quickly developed new methods for constructing their receivers. For a start, the top-of-the-line receivers needed to be more elegant in appearance. They also had to perform better and be easier to operate than the early 1920s sets.

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