Offered here is an original Siemens field-coil unit / field-coil loudspeaker component, believed to date from the early 1930s. The field winding is made with approximately 0.28 mm solid copper wire and offers an attractive basis for restoration, technical study, collector display, or carefully planned vintage-audio projects.
Field-excited loudspeakers were widespread in the 1930s, before strong and stable permanent magnets became readily available. Their energized field coil created the magnetic field and was often also incorporated into the radio’s power-supply filtering as a choke. Siemens used electrodynamic loudspeakers with field excitation in radio equipment of the period.
Please study the photographs carefully, as they are an essential part of the description. Dimensions, resistance values, voltage requirements, polarity and wire specification should be verified by the buyer before installation or operation.
This component may be of particular interest to experienced restorers, field-coil enthusiasts and audiophile DIY builders. Potential applications—following proper testing and evaluation—include:
The appeal lies in the original 1930s Siemens construction and authentic copper winding.
A field coil may require substantial DC voltage and current. Do not connect it directly to mains power or an amplifier output. It must only be tested or operated by qualified persons using a suitable current-limited DC supply and appropriate circuitry.
The item is sold as a historic, untested component with no guarantee of electrical functionality, safety or suitability for a specific project.