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Enrico Tedeschi, e.tedeschi@ndirect.co.uk
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Sinclair products enjoy a collectable status mainly because they have often been at the forefront of the technological advance.
Unfortunately in the case of the radios Sinclair was slow and late (the Regency TR-1, the first transistor radio was put on sale in the USA in November 1954). However their collectability is assured by the fame of their British electronics wizard: Sir Clive Sinclair.
The first one of the Sinclair micro radios came out in early 1964 and was called the Slimline. It used the now famous Micro-alloy transistors which Sinclair was buying cheaply as rejects and badging them with his own model number after checking and testing them in a small room in a building just off Chancery Lane, London.
It was supplied only as a kit and, as later became common of the Sinclair's micro radios ad blurb, it claimed to give you "Europe in the palm of your hand" while using its "featherweight quality earpiece".
The fact is that many listeners were keen to tune into a continental pop music station called RADIO LUXEMBURG which was very popular a the time and so Sinclair ads were suggesting that, with 49 shillings and 6 pennies you could own your own piece of advanced (!?) electronics able to pull this station in, was really a crowd catcher.
But Sinclair, who had always been fascinated by diminutive items, pressed on for miniaturization and in early 1964 came out with "the smallest set in the world": the MICRO-6.
While this claim might not be completely true (The Japanese Micronic Ruby was a comparable sized set but a real superetherodine radio receiver with a loudspeaker) the set was really tiny and used the usual MAT transistors to give a "six stage sensitivity". What was really happening inside was that, with only three transistors, two stages in Hight Frequency were followed by three stages in A.F. after detection.
The ad blurb stated that the set really "played in car, train, bus or plane" as a reassurance for anybody who could have feared the contrary.
It was still an earphone only radio but it sported its own "self-contained ferrite rod aerial and batteries"
The third model, which came out in late 1965, was the MICRO FM, a fully fledged 7 transistors (and two diodes!) superhet circuit "incorporating many unique and original design features to achieve fantastically good standard of performance"
This one too was still supplied only as a kit and therefore appealed only to the home electronic tinkerer of the time.
The last, and most popular of Sinclair's micro-radios, was produced in 1967. To keep the cost low the number of transistors was reduced to only two while still boasting a "six stage amplification".
The usual claim to be "the smallest set in the world" was achieved (if at all) by the use of a small compensator instead of a fully fledged variable capacitor, just like the other sets did in their time.
This time, perhaps in the effort to appeal to the more general public, the set was supplied also as an already built receiver. While still an hearphone receiver, the advertising pictures showed a series of small holes undeneath the tuning dial, perhaps trying to hint that it contained a loudspeaker which of course it didn't.
At least two version are known to exist and they can be distinguished by the earphone socket, one of which is on the opposite side of the other.
CONCLUSION
Sinclair's micro radios did not shake the world when they came out but they are worth putting by for their historical and nostalgic importance.
BIBLIOGRAPHY
- The Radio constructor magazine
- Practical Electronics magazine
- The Sinclair Story by Rodney Dale, Duckworth publishers (1985)
- House leaflets and brochures
- Sinclair Archeology by Enrico Tedeschi, Hove Books, 1996
Copyright © 1996 Enrico Tedeschi
Enrico Tedeschi, e.tedeschi@ndirect.co.uk
Page maintained by webmaster@Brighton-UK.com