COLUMBUS MODEL 18 (1937)

The Columbus model 18 was manufactured for Columbus Radio Centre Ltd by Radio Corporation of New Zealand Ltd in 1937.

There were several different cabinets for this dual-wave model, and the Columbus models started one year after production began (because the Columbus brand name was not introduced until 1937, while the model 18 had been introduced the previous year under the Stella, Pacific and Courtenay brands).

The model 18 has 4 knobs, but some examples have 6 - these are vibrator power supply versions, designed to run from a 6V battery.

 

 

Valves (6 + eye): 6D6, 6A7, 6D6, 6B7, 42, 80 and 6E5 magic eye on some models

Intermediate Frequency: 456kc/s

Frequency Bands: 2

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

Model 18 chassis, found in chest-style and tombstone cabinets, sometimes with a vibrator power supply. Dual wave. Radiomuseum has a tombstone without magic eye, and the schematic does not show one, yet many examples have an eye fitted. Production serial numbers have been noted in both 1936 and 1937.

The standard chassis has 4 knobs - although many model 18's have 6, which indicates a vibrator power supply is fitted and it is designed to run from batteries or mains.

1937 Columbus model 18 Schematic

General Construction Notes for Radio Corporation of New Zealand Ltd:

The first digit of the serial number typically indicates the year of manufacture of RCNZ chassis' (although not the decade - that requires a little knowledge of the valves, construction, etc). Sets from around 1934 onwards were often (but not always) constructed in a distinctive pressed 'baking pan' style chassis, seemingly unique to RCNZ.

Model codes beginning with a 0, for example the model 051, are Osram valve versions of the model without the leading 0. Technically the 0 should be an O (for Osram), however the digit 0 was used throughout the site before this fact was discovered.

The E suffix indicates a magic eye option is fitted (in models which were available with or without, such as the model 25).

A and B suffixes appear to be simply updates to the current model, R also appears to be simply an updated model ('R'edesign, perhaps?)

P indicates either a permanent magnet speaker version of a model which also came with an electromagnet speaker (the model 26 for example), or a portable model (like the model 694P).

N and M indicated miniature valve versions of a model which started with all (or a mix, ie: model 5) of larger valves. One of these two codes may indicate a transitional mixture of octal and miniature - clarification is required.

S often indicates a stereo model.

Finally, other suffixes and prefixes make occasional appearances in the RCNZ lineup - like the 66W (a variant of the long-running model 66) and the 75XA (a 10-valve version of the model 75 with a separate amplifier chassis).

All documented models using this chassis (4 in total)

YEARMODEL NAME
1937Columbus model 18 - this set
1936Courtenay model 18
1936Stella model 18
1936Pacific model 18