1939 STC Console Radio model 633​

This radio is a STC (Standard Telephones and Cables)  Model 633 console radio. The earliest advertisement is in The Wireless Weekly, March, 1939. This was a mid-range model for that year (1939) with a 6 valve circuit, a magic eye tuning indicator and sold for 31 Guineas. It received AM (MW) and two SW bands.

How much did a model 633 cost?

STC radios sold from 13 Pounds for a small 4 valve mantle radio, to 39 Guineas for their top of the range 10 valve console radio.

Features

• Vacuum Pressed -S.T.C.’s. Handsome Cabinets are constructed under the new vacuum pressing process, which combines. Superior finish with greater rigidity and strength.
• Freewheel Tuning -Tuning-in is made easier by the new freewheel tuning. The lightest flick of the finger on the tuning knob sends the dial pointer speeding around to the station you want You will like the velvety smoothness of Freewheel Tuning
• Richer Tone -S.T.C. Radio has always been world famous for its tone quality. In the new models, the tone is even better. Bass notes are richer and deeper. Treble notes are clearer and more brilliant. For tone, the new S.T.C. models stand alone.

Standard Telephones and Cables Pty Ltd Origins

Standard Telephones and Cables Pty Ltd  had its origins in Australia back to 1885 when it began selling telephone equipment manufactured in the UK and other parts of the world. Manufacturing of telephones and radios commenced in 1926 in Chippendale, Sydney.

By 1935 the factory at Chippendale was unable to cope with the company’s rapidly expanding business. Land was acquired in Alexandria and a new factory of 30,000 square feet was established. By 1939 the company’s employees numbered 500 and the factory had increased to 27,000 square feet.

Preserving and Bringing Life to this 1939 Radio

This radio was acquired through the Sound Preservation Association of Tasmania in 2022. It was in bits and the cabinet had been partially stripped of the original varnish and apparently been in a shed fire. The knobs, speaker board, grille cloth and grille cloth and ornamental bars were missing.

The original 10 inch speaker was present and in good condition. It was common for radios of this period to go in for repair every few years as some of the parts were not as durable and reliable as they are today.

Previous work had been done on this radio with the replacement of the original tone control with a combination on/off-tone control switch. The amplifier circuit worked well, however, the radio circuit did not. All the old wax/paper capacitors were replaced one by one, and it was only when the last capacitor in the most inaccessible location was replaced that the radio circuit came back to life.

Safety is important with Vintage Radios

Radios of this era also were not as electrically safe as they are today. In bringing this vintage radio back to life it has been made electrically safe with the provision of a  fixed connection to Earth and a fuse.  Even so, the voltages operating inside these old radios is very much higher than in modern domestic appliances so that tampering inside the radio is strictly prohibited.

Modernising the 633 with Bluetooth

As a part of modernising the radio, Bluetooth has been added to enable connection to smart devices. See the instructions to enable this. In this case, a small 5volt DC circuit has been added to an existing 6.3 volt AC line in the radio to produce the power to run the small Bluetooth circuit. To help balance the audio output of the Bluetooth circuit with the radio signal output a small amplifier circuit has been added to the Bluetooth.

Repurposing existing sockets and switches

These radios were almost always fitted with ‘Pickup’ sockets to enable a record player to the connected to the radio amplifier circuit so the records could be replayed through the radio. In the STC model 633, there are two terminals on the back of the radio chassis enabling easy connection of the Bluetooth signal to the amplifier circuit. This radio also has a redundant position on the band selector switch that was used to connect the Bluetooth and disconnect the radio circuit at the same time.

Maker of the Cabinet

The cabinet has the maker’s label of Jackson and Macdonald, Sydney.  Jackson and Macdonald commenced in 1906 as a wholesaler selling Edison cylinder records and phonographs. The next step was to import motors, tonearms, and soundboxes from S.A. Thorens, Switzerland, which were assembled in Sydney to locally made talking machine cabinets and sold under the ‘REXOPHONE’ trademark. The business prospered and a cabinet factory was established. The peak of production was reached about 1928/9 when more than 100 people were employed at the cabinet factory, and 120 people in the warehouse. With the Great Depression and the collapse of the talking machine business, the cabinet factory turned to making radio cabinets that were supplied to various radio manufacturers and also to clock cases.

Detail of the Cabinet

The cabinet is made of highly figured Walnut (central panel and sides), highly figured Maple (side front columns), and imported Zebrano veneer (vertical ornamental struts).

The grooved timber mouldings on the top of the cabinet, painted black, give a nod to the step-down mouldings of previous years. This feature also balances the black feet at the bottom of the cabinet.

The large side columns of figured Maple are much broader than cheaper models of the same manufacturer and give an impression of a much more solid, substantial cabinet. They echo a ‘monumental entrance’ which was a popular feature in architecture during the art deco era.

The vertical struts of the Zebrano veneers reinforce the vertical columns and contrast with the rectangular dial which is laid horizontally and the control knobs also laid horizontally.

The grille cloth in front of the speaker is a period replacement from the same manufacturer, STC.

The Author and more Resources

Your vintage radio collector Malcolm Grenness is a member of the Sound Preservation Association of Tasmania, the Historical Radio Society of Australia and Radiomuseum.org.

There is more information on this actual radio on the Radiomuseum.org website. This vast archive and community of radio collectors features over 120,000 radio model listings and 350,000 photos and schematics.

Quick Links

• Radio Museum
• Radio Museum – The 1939 STC Console Radio model 633
• Sound Preservation Association
• Historical Radio Society of Australia
• Instructions to use the Viriditas Accommodation 1939 Radio model 633