This radio was designed and made by the donor in 1951. In this radio's design David Hain sought to create a new and compelling feature that would set it apart from other radio designs. David wrote to AWA, a large Australian radio manufacturer, about this radio design seeking to generate interest:

"I have been experimenting for some time and have satisfied myself that I have found such a feature. I have built a set incorporating it, and not interfering with the previously mentioned features. Those of my friends to whom I have shown it, think it is a great idea, and I think you would too."

At this stage of the research and documentation of this radio it was thought the radio would not surrender the secret of its innovation. However a small note wrapped around a used capacitor stored in the back of the radio revealed the answer:

'This 500uF, 12 Volt capacitor was replaced (23 June 1991) by a 680uF, 40V Philips component. It had been in my quick heating AC table model radio since I built it about 40 years ago. It had 'dried out' and lost capacitance causing an annoying hum.'

A quick heating circuit certainly would have been a feature enjoyed by valve radio users as valve sets took some time (5 - 20 seconds) to warm up after being switched on before radio reception was produced. David's quick heating circuit design may have interested AWA however there is no further correspondence regarding this and there is no evidence that it was incorporated in further radio design. The application of transistors to radio circuit design within the next decade had eliminated this 'problem'.

The 'quick heating AC table model' radio was designed and made by David Hain, Sydney, Australia, 1951. The acquisition includes circuit diagrams and notes by the donor describing the design and its purpose. In this radio's design David Hain sought to create a new and compelling feature that would set it apart from other radio designs.
'I have been experimenting for some time and have satisfied myself that I have found such a feature. I have built a set incorporating it, and not interfering with the previously mentioned features.'

A small note wrapped around used capacitor stored in the back of the radio revealed the innovation;

'This 500uF, 12 Volt capacitor was replaced (23 June 1991) by a 680uF, 40V Philips component. It had been in my quick heating AC table model radio since I built it about 40 years ago. It had 'dried out' and lost capacitance causing an annoying hum.'

A letter from David Hain to AWA explains the history:

'Dear Sir,

With the prices of radio sets rising as they are, the public are giving more careful consideration as to the merits of the different radios available, and deciding what set will give them the best value for their money. A large majority of people, having no understanding of the technical side of radio, judge by the most easily noticed features such as:- appearance, tone, easily read dials, ease of moving mantel sets, convenience of having built-in switch, all Australian made parts and valves, etc. and also a well known brand.

While 'Radiola' compare very favourably with other brands in most of these features, an additional feature, obvious to all people and not possessed by other brands, would be a very great attraction to the A.W.A. product.

I have been experimenting for some time and have satisfied myself that I have found such a feature. I have built a set incorporating it, and not interfering with the previously mentioned features.

Those of my friends to whom I have shown it, think it is a great idea, and I think you would too.

If you are interested enough to write to me, I will be pleased to tell you more about it and arrange a demonstration for you.

Yours sincerely
D.W.Hain'

Radio receiver, 'quick heating AC table model', and documents, wood / glass / electronic components / metal / plastic / paper, designed and made by David Hain, Sydney, New South Wales, Australia, 1951

Wooden radio with curved front edge, square speaker section with two bar grille and coarse woven brown cotton cover. Square frequency dial at right with plastic moulding surround.Three control knobs below dial.
Two hand drawn circuit diagrams.
Note regarding the capacitor.
Note with phone and street address for W.K.Pulford.
Hand written copy of a letter from David Hain to Mr Pulford of AWA (2 pages, March 4th 1951).
Letter in response from Pulford on plain paper (21 March 1951).
One capacitor.

Made: Hain, David; Sydney; 1951

2007/17/15

1951