Compact Loudspeaker Crystal Radio

This is the compact version of my 'Loudspeaker Crystal Radio'.

Compact Loudspeaker Crystal Radio

Trials on a number of assorted audio transformers, from the junk box, were not in vain. A push-pull output transformer, intended for a 1 W germanium transistor audio amplifier, gave excellent results.

Compact Loudspeaker Crystal Radio - Schematic

The centre-tap on the primary is not used.

A discarded blister pack serves as the base.

In spite of its small size, performance is as good as that of its counterpart.

My 'Homebrew Horn Speaker' and 60' wire antenna offer the perfect match for this crystal radio.

Related post: Alternative Detector for a Shunt-fed Crystal Radio
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Makeshift Piezo Earphones

A makeshift piezo earphone arrangement comprises a stethoscope and a piezo transducer.

Stethoscope

The sound emanating from the transducer is captured by the bell of the stethoscope, held against its face.

Piezo Transducer

This arrangement was recently used to figure out how to interface a piezo earpiece with a crystal radio. The transducer, a 1¾" telephone ringer, was salvaged from the junk box.
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