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SILICON SILIC CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Editor Nicholas Vinen Technical Editor John Clarke, B.E.(Elec.) Technical Staff Ross Tester Jim Rowe, B.A., B.Sc Bao Smith, B.Sc Photography Ross Tester Reader Services Ann Morris Advertising Enquiries Glyn Smith Phone (02) 9939 3295 Mobile 0431 792 293 glyn<at>siliconchip.com.au Regular Contributors Brendan Akhurst David Maddison B.App.Sc. (Hons 1), PhD, Grad.Dip.Entr.Innov. Kevin Poulter Dave Thompson SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490. All material is copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing and Distribution: Derby Street, Silverwater, NSW 2148. Subscription rates: $105.00 per year in Australia. For overseas rates, see our website or the subscriptions page in this issue. Editorial office: Unit 1 (up ramp), 234 Harbord Rd, Brookvale, NSW 2100. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9939 3295. E-mail: silicon<at>siliconchip.com.au ISSN 1030-2662 Recommended & maximum price only. 4  Silicon Chip Publisher’s Letter Cutting-edge technology – in 1958 These days the pace of technology change is so rapid and so all-pervasive that most people would have forgotten that this rapid change started to happen more than 60 years ago with the introduction of transistor radios, mostly made in Japan. Before that, all radios were valve-based and many western countries had their own electronics industries, largely devoted to the manufacture of valve radio and television sets. In a little more than a decade or so, Japan changed all that. In fact, Japan basically obliterated the domestic electronics manufacturing industry in most western countries. Nowadays many people worry about the loss of jobs to Asian countries but it all started with Japan. Not only were labour costs far lower in Japan than in western countries but the Japanese were leading the way with new technology. That fact is highlighted by Ian Batty’s story on the Sony TR-712 7-transistor mantel radio in this month’s Vintage Radio pages. This set was introduced in 1958 and it had only been in 1954 when the first transistor radio appeared (see SILICON CHIP, April 2013). Those first transistor radios were largely novelty items and their main attraction was just how small they were – you could stick them in your shirt pocket. In all other respects, those early “trannies” were woeful. They sounded awful, as anyone who can remember their “squark, squark” reproduction will attest, and their RF performance left a great deal to be desired. Their battery consumption was also very poor and for two particular reasons. First, as the battery voltage dropped, the bias in the class-B output stage became less and less optimum and severe (very severe) crossover distortion was the result. Second, once the battery voltage dropped by more than about a third, the local oscillator would fail to work and therefore the radio itself was out of action. But while the technical fraternity might have sneered at their shortcomings, preferring the much better sound of valve radios, the man in the street was greatly intrigued and “trannies” became exceedingly popular. And then Sony brought out the TR-712. This set was far ahead of any transistor radio previously on the market. This clearly showed that Sony was the absolute leader in transistor technology. Not only did it use a mixture of NPN and PNP transistors where previous transistor radios had been PNP Germanium types, but it also used new circuit techniques; neutralisation in particular. Actually, neutralisation was not new and had been used in valve sets for years but this was the first time that it was used in a transistor set. To explain, early transistors had very poor RF gain and NPN transistors were generally much worse than PNP types. Neutralisation is essentially a positive feedback arrangement which gives a boost to the high frequency gain. It demonstrated that the Japanese were making giant strides with this new technology and the resulting performance of the TR-712 was way ahead of anything that had been seen before. It must have really made engineers in western countries sit up and take notice. But from that point on, they never really caught up, in spite of the introduction of silicon epitaxial transistors and so on. Whether it was TV sets or domestic hifi equipment, Japanese manufacturers completely dominated the market in Australia and virtually everywhere else except in the iron-curtain countries where severe import restrictions were enforced. Then the Whitlam Labor government administered the coup-de-grace to the Australian electronics industry with its across the board tariff cut of 25% in 1973 and then it was virtually finished. Funnily enough, there is still quite a lot of specialised electronics manufacturing still going on in Australia and Japan is now merely a small part of the huge Asian phenomenon. Leo Simpson siliconchip.com.au