The Bell Colt 3B7 Champ was manufactured by Bell Radio-Television Corporation Ltd in about 1957.
This model is part of the Bell Colt series of radios.

The 'cheap' 3-valve (4-valve equivalent, taking into account the rectifier) Colt

The Bell Colt 3B7 Champ is part of the Bell Colt series of radios.

Bell Colts ran from 1951 through until 1980 - the longest running model of NZ built domestic radio.  It saw many different engineering changes over the years, and the last few models dropped valves in favour of new transistor technology.  There is considerable information on the main Colt page about this Kiwi icon.

The radios in this series are:
1951 Bell Colt Original
1954 Bell Colt 5B4
1955 Bell Colt 5B5
1957 Bell Explorer Colt
1957 Bell Planet Colt
circa 1957 Bell Colt 3B7 Champ Colt
circa 1957 Bell Colt Cadet
circa 1961 Bell Colt All Transistor
1967 Bell Colt 5B67
circa 1968 Bell Solid State Colt
circa 1975 Bell Solid State Colt Mk III

Technical Information

Valves (3 + selenium rectifier): ECH81, EBF89, ECL82, Flat Selenium Rectifier

Frequency Bands: 1

Chassis Notes(most schematics can be clicked to download a full size version)

This Colt uses standard tuning... the other three-valve set (the 'Cadet') uses permeability tuning (no tuning gang, moving slugs inside coils).

Bell Colt Champ Schematic