CANADIAN MARCONI HOME ENTERTAINMENT - TRIUMPH SERIES This document will feature radios in the Triumph series. Model numbers in the format of 48-xxxx are vendor catalog numbers from whichever dealer happened to be selling Marconi radios. Triumph series radios had nine tubes and were made in 1929. The Triumph line covered models 15, 16, 17, and 18. The sets in this family cane as "batteryless" and "battery operated" . One of the tubes in the sets lineup acted as an aerial coupler to compensate for varying lengths of aerials. This tube had a further function - It enhanced selectivity by employing a 4 gang tuning capacitor.
Note the notation "Complete With Tubes" in data sheet #2. To keep costs down to the bare minimum, early radios were sold with and without tubes. When purchasing a "without tubes" radio, this gave the customer the option to provide their own new or used tubes. This practice started to fall by the wayside in the late 1920/s or early 1930s.
Until the appearance of the AC power supply around 1930, radios depended on batteries for their operation, .Once AC power supplies became commonplace, the marketing folks started to incorporate the term "batteryless" as a feature of the radio. Once all radios were provided with AC or AC/DC power supplies, that term also disappeared from usage.
Contributors or References:1) Lewis Bodkin <05bodkin555(at)gmail.com>
May 11/19