The Bell Colt Original was manufactured by Bell Radio-Television Corporation Ltd in 1951, production ran for about 3 years.

The original Bell 'Colt'.  Believed to be identifiable by having 5 rimlock valves and no chassis model marking - the next known model, the 5B4, does have its model code stamped on the chassis (most, but not all).  This set was one of the first to carry the Bell name, and the first in a line of Colts that would span almost 30 years and sell in the 10's of thousands.

Valves (5): ECH41, EF41, EBC41, EL41, EZ40

Intermediate Frequency: 462kc/s

Chassis Notes (most schematics can be clicked to download a full size version): David Clist noted an issue with the tone control circuit producing high harmonic distortion at the full bass position - although as most people never set the tone control here its unlikely anyone would have ever noticed. RJ Hatton notes in his 3-part series on the Colt (October 2004) that 100pF caps in this model could prove to be unreliable and cause a crackling sound (possibly a form of silver mica disease). I.F. transformers are ETA round-cans. These were on early 5B4 models as well.

All documented models using this chassis (2 in total)

1951Bell Colt Original - this set
1953Rolax Colt