Radio, Grebe Synchrophase; Grebe; 1925-1927; Unknown


Radio, Grebe Synchrophase

About this object

This Grebe Synchophase is an American TRF 6 valve receiver. Introduced between 1925 and 1927, it features mechanically coupled tuning capacitors linked via clutches to provide a degree of single knob control. This model was judged by many to be the most handsome of the mid-1920s TRF receivers.

An Illegal Radio:

The Synchrophase is a Neutrodyne circut. This became an issue for Grebe because Neutrodyne circuits were owned by the Independent Radio Manufacturers (IRM) who had paid Louis Hazeltine to design it exclusively for them. Grebe was not an IRM member and they were building a Neutrodyne,. Though a law suit was inevitable, Grebe’s production of Neutrodyne was never stopped. Synchrophase production reached 150,000 radios before the court even heard the case in June, 1927 and by that time, the Synchrophase was already obsolete. While Grebe lost the case, they were able to obtain a Neutrodyne license anyway.



Maker Role


Date Made




Place Made

North and Central America, United States, New York State, New York

Medium and Materials

organic, processed material, vegetal, wood, mahogany?
inorganic, processed material, metal, alloy, copper alloy, brass
inorganic, processed material, synthetic, plastic, bakelite
inorganic, processed material, glass
inorganic, processed material, metal, copper
organic, processed material, vegetal, fibre, cotton

Inscription and Marks

Printed onto the centre face of the radio: 'GREBE SYNCHROPHASE'.


h 240 mm x w 565 mm x d 330 mm

Subject and Association Keywords

Communication (including Diaries and Letters)

Object Type


Object number


Copyright Licence  

Attribution (cc) Attribution (cc)

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