S.P.A.R.C. Museum

Society for the Preservation of Antique Radio in Canada

Photo of tool handles in the restoration workshops at the SPARC radio museum

The SPARC Museum has two main workshop areas:

Cabinet Work Area

Photo of the cabinet restoration workshop at the SPARC Radio MuseumApart from the dial, the cabinet of a domestic radio is the most looked-upon feature. Radio cabinets in the very early days of radio (pre-1920) were utilitarian in nature, serving only to house some of the components – the tubes were often exposed – made out of ebonite or wood, showing-off the ‘new technology’. By the early 1920’s, cabinets began to be made of wood, often solid hardwood, but were generally simple in nature, many being only a simple box with a hinged lid for access (‘dog coffin’), with an ebonite, metal or Bakelite front panel. By the late-1920’s, however, radios were becoming embedded in everyday life and their cabinets began to become pieces of furniture in their own right, such as to blend in with the surroundings in the home. Instead of solid wood, plywood was by this time mostly used, with high quality veneers on the outer surface. The finish applied was generally a lacquer, but sometimes French Polish or Shellac was used. This trend persisted through the 1930’s, although many table radios were made from Bakelite and plastics that were often works of art. By WWII and afterwards, radios again became more utilitarian in nature, with cases generally being made from Bakelite and other plastics, with wood becoming less prevalent.

Over the decades, cabinets of all types often became damaged through wear and tear (pets, kids, house moves, plants placed on the top leading to water damage, etc.) and through neglect, the latter including years of being left out in barns, damp basements and other less-than-ideal conditions. The end-result being cabinets that have peeling veneer, scratches, score marks, warping, weakened joints etc. However, through careful assessment, planning, patience and skill, most can be restored to their former glory (or better!).

The SPARC museum has an excellent cabinet workshop in the rear of its premises: well-stocked cabinets of all the necessary materials, tools and a fully-ventilated and equipped spray booth. Many fine examples of cabinet restoration efforts can be found in the projects section of this website. Many of our volunteers spend hours in this hive of industry: cleaning, repairing, stripping off old lacquer, carefully preparing the wood by filling, sanding, re-veneering if needed and oiling prior to applying coats of new lacquer, tinted as required to provide a close match to the original finish. We restore cabinets for sets in our display, for members of the museum, and for members of the public that bring in their family heirlooms and wish to bring them back to their former glory.

Electronics Work Area

It is no use having a great-looking cabinet without a working chassis to go inside it! As cabinets changed over the years, so did the technology inside them – many think that a ‘tube set’ is a ‘tube set’, but there are a great many differences between sets made during the early decades of the last century – the ‘tube era’. The tubes themselves evolved from simple diodes and triodes in the early 1920’s to the ‘screen grid’ and pentode tubes by the late 1920’s. This meant that the number of connections made to the tubes increased, leading to a variety of tube base designs (eg. four, five, six, seven, eight and nine pins, plus top cap(s) on some designs). Circuit complexity and ingenuity developed through the late-1920’s and 1930’s, from ‘tuned radio frequency’ (TRF) designs to ‘superheterodyne’ designs in the early-1930’s, leading to yet more tube designs, often incorporating two or more tube functions within one envelope to reduce the number of tubes and thus allow more economical and compact construction. Sets through to the mid-1920’s were battery-powered, with mains-powered radios only entering the market in the late-1920’s when Rogers introduced the ‘AC tube’, this having an indirectly-heated cathode. All-metal tubes were introduced in the mid-1930’s and by the late-1930’s, ‘miniature’ tubes were developed, allowing further reductions in physical size of radios. So-called ‘passive’ components in radios of this era were prone to age-related failure – mainly caused by moisture ingress or use of materials having poor ageing characteristics (but who would have thought that these radios would still be in use over 70 years later?).

Knowledge of all of the above (and much more) is essential in being able to diagnose faults in radio circuits and to restore them to their original functionality. Access to a set’s schematic and a range of reference books and manuals is often needed by the repairer, and the Museum has a wide selection of these to hand. Also, many vintage radios included ingenious and often complex mechanical arrangements for tuning of pre-set functions, and restorers need to be able to assess, understand and repair these mechanisms – patience is a real virtue for this.

Located at the front of the museum, the SPARC electronic workshop is equipped with a wide variety of test equipment and a good stock of spares, including a ‘tube vault’ and a ‘behind-the-scenes’ storeroom packed with radio chassis and spare parts. Some of our volunteers have professional radio repair backgrounds, others have backgrounds within the radio industry, and/or are self-trained in the repair and restoration of vintage electronics, able to troubleshoot, diagnose and repair a wide variety of chassis types. Many examples of restored and repaired chassis are presented in the ‘projects’ section of this website.