Later version of the model 5. Note also the factory (presumed) motel version with 6d coin slot.
Intermediate Frequency: 455kc/s
The model 5 was originally spec'd to use an octal 6K6** output valve, although its likely that most have a 6V6. There is also a release note stating it would most likely change to be a 6AQ5 in time. It also used an octal 6X5GT rectifier. All subsequent models have a full miniature valve lineup.
The later versions also had a better spread of the frequency band as can be seen in the comparison photo of the early model 5 dial and the later ones.
The model 5B has a wider dial, with a narrower speaker grill to compensate, and uses a standard aerial coil rather than the loop aerial the other models have.
**Of interest is the valve lineup provided by the release notice sent to Columbus Radio Centres (see below) - the output valve is listed as a 6K6, which may be updated later to a 6AQ5. The 6K6 is a lesser known cousin of the venerable 6V6 and RCNZ must have had a few of these rarer output valves for them to spec it into the set - although the official RCNZ schematic shows a 6V6GT. Of course, all subsequent variants of the model 5 used 6AQ5 miniature output pentode.
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.
|1950||Courtenay model 5|
|1950||Columbus model 5|
|1951||Columbus 5M - this set|