Recording and mastering studio in Toronto, Ontario. Operated under this name from 1954 until 1979, it housed two recording studios, Studio A and Studio B.
Records cut at this studio are identified by "TG", "GT", "TXG", "TXD" "TD", "XT", "ZDT", "TX", "DT" etc. etched in the deadwax/runoout.

The "T" stood for Toronto and the other letter(s) indicated the quality of the source material used, sometimes used in combinations:
G = good source
X = poor source (distortion, sibilance, pops, etc.)
D = source had distortion
Z = source had sibilance

Originally founded in 1948 by Toronto media company CHUM Ltd.. Around the same time, RCA Records started a recording operation in the Royal York Hotel.
In 1954 CHUM Ltd. sold the studio to RCA Records.
In 1979 RCA Limited sold the studio to McClear Place Studios Ltd. and renamed to McClear Place.

Engineers known to have worked there (and McClear Place):
1948-1983 Bill Dowding
196x-1973 Fred Burchill
1962-1967 Peter Houston
1964-1966 Graham Newton
1965-1975 George Semkiw
1969-1976 Hayward Parrott
1970-1976 Alan Moy (etch as "GAM")
1974-1987 David Balan
197x-197x John Curl
197x-197x Cub Richardson
197x-198x Kevin Fuller (etch as "KF" and "K.E.F.")
197x-198x Colin Murphy