The JLH Gateway-- A Golden Jubilee Tribute

Building the JLH Classic --  Milestones of the Era Today, as we look back and focus our sights on the JLH Classic, it would be educative to broadly, though briefly, survey the audio electronics landscape of the era. Unarguably that alone would reveal the correct perspective regarding the genius of JLH and his timeless design, rather than label his class-A amplifier as 'one of the typical designs' of the era. Happily the JLH Class-A was not just another 'typical design' of the period -- it had nothing that went before it, and on which it was based. Not only that, the design had many unique features despite appearing to be quite basic. Suffice to say, its apparent simplicity hid within itself many subtleties of design not easily revealed to the casual investigator or circuit hacker. No wonder it has defied the efforts of many talented designers to 'pin it down' and analyze it threadbare.  GOM and old timer Nigel Pearson has put it wonderfully thus: "It makes ...

Building the JLH Classic --  The JLH Archives           Looking back, it can be seen that 1969 was an epochal year for JLH fans -- the Master published the iconic "Simple Class-A Amplifier" in April and later, in July of the same year, the "Modular Pre-amplifier Design" in the Wireless World magazine, the grand old dame of UK "wireless" publishing. As they often say, "the rest is history"! History continued to be made in the long fifty years plus after the publication of that article by ardent enthusiasts and DIYers.           True to the article title, the design presented an extremely simple (and elegant!) class-A power amplifier with just four transistors and a handful of passive components, which could often be scrounged from the 'junk box' of the average DIYer. As is often the case with class-A amplifiers, the expensive parts were the rather substantial (when compared to class-B amplifers) heatsinks and the heavy powe...

Gateway to Class-A -- Building the JLH Classic-1969 John Linsley-Hood (1925 -- 2004) Audio designer nonpareil John Linsley-Hood -- Truly a legendary name in audio electronics, whose signature Class-A amplifier design has achieved cult status and the 'classic' moniker in our times. More than half a century after publication (in Wireless World, April 1969), his "Simple Class-A 10 W amplifier"  is considered unmatched in simplicity and subjective audio quality. In this series of posts my attempt is to preserve for enthusiasts and DIYers the work of this great man, and perhaps offer a gateway, a "single window", into the audio world of 'JLH' (as he is fondly known worldwide), with the stress on the Classic-1969 design. The material presented here from authentic archives and other sources in my decades-old collection, is sure to keep enthusiasts occupied for many summers and winters, reading, building, and enjoying the fruits of the build in the manner...

          The JLH Gateway is presented as a tribute to the prolific designer and the great soul that John Linsley Hood was. It is a not-for-profit endeavour, and readers are earnestly requested to read, comment and add to the material presented here in case they have access to such material that have not yet been included, and also offer corrections and edits, if any.           The JLH Gateway offers a single window of access to virtually the entire corpus of articles  published by John Linsley Hood during his lifetime -- at least all those that have received the attention of readers of the various audio and electronics journals of the era. A few articles (from Hi Fi News & Record Review) have evaded my efforts to source archival copies, but with the help of our readers, I am sure that lacuna will soon be filled.           The Posts are divided into two sections -- the first section...