As with most electrical firms in the 30's, Cory-Wright and Salmon had their own radio brand: Stella. Originally they were manufactured for them by Radio Corporation of New Zealand, and after 1937 by Collier and Beale - but it seems that by the late 1930's they had gotten out of radio and the brand disappeared, and while later model Stella radios exist, they were not related.
Portrait of (L to R) Mr Salmon, Mr Cory-Wright and John Cory-Wright standing in front of visiting British Vickers Viking passenger plane G-AJJN, Whenuapai Airport, Auckland City. Whites Aviation Ltd: Photographs. Ref: WA-07072-F. Alexander Turnbull Library, Wellington, New Zealand. /records/30635307
Excerpt (abbridged) from Te Ara - the Encyclopedia of New Zealand
In 1920 Silston Cory-Wright joined Cedric Salmon, a fellow officer in the Engineers, in founding the engineering firm of Cory-Wright and Salmon. The business was based on the partners' contacts with such major British firms as Vickers Limited and the English Electric Company, but it also represented over 50 other large engineering concerns. It supplied a diversity of equipment, especially for railways: electrical components for the Lyttelton–Christchurch line (1928), electric units for the Wellington–Johnsonville line (1938), and electric locomotives for the main trunk line beginning with Wellington–Paekakariki (1939–40).
Contracts were also obtained through Cory-Wright's interest in hydro development. On behalf of the firm he supervised Escher Wyss turbine installations at Lake Coleridge until 1923, and subsequently many hydroelectric units for English Electric. By the 1950s he had been associated with every significant South Island power station and with several in the North Island. He was closely involved with the firm he cofounded until his death in 1976. The partnership had become a private company in 1931 and a public one in 1951. The firm was taken over by Tatra Industries Limited in 1983–84, and went bankrupt in 1988.
Reference: F. Nigel Stace. 'Cory-Wright, Silston', Dictionary of New Zealand Biography, first published in 1998. Te Ara - the Encyclopedia of New Zealand, https://teara.govt.nz/en/biographies/4c37/cory-wright-silston (accessed 23 June 2019)