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The JLH Gateway to Class-A :: 11

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The P-N-P Pandemic !           The audio scene, just like the fickle fashion scene, is prone to trends and fads that surface with some regularity out of the blue. One such trend/fad that gained some traction around 2015 or so was the 'P-N-P Fever' -- every (not exactly true...but still!) JLH fan and DIYer was swearing by the 'sound' of a JLH Classic implementation with PNP transistors in the output. And the Chinese kit retailers made good money out of old stock devices or fakes or whatever. Their lack of knowledge of English stood them in good stead, as nobody expected an instruction manual or even a circuit diagram-- it was just a PCB and some parts and sometimes even a fairly good cabinet and some average heatsinks -- but all bundled at an unbeatably low price! In all honesty, I must admit that some kits with old Sanken and other respected brand 'audio transistors' offered good value for money for the hobbyist who knew his ropes well.      ...
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The JLH Gateway to Class-A :: 10

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The Master's Voice ...  and More           Building the JLH Classic amplifier takes quite a bit of artistry in that one must judge the 'musicality' of the amplifier -- a factor that its designer had set much store by. For JLH the designer, engineering concepts were only the means to achieve 'subjective truth in amplification'. But of course, he was not a pure subjectivist; nor was he fully in the 'objective/measurements' camp. As he easily walked the middle ground, we could see that  his genius and artistry lay when, with aplomb, he blended the art and science of amplifier design. Half a century (and more!) has passed since he had given the world his 'simple' amplifier, but still it continues to exude audio truth as he had envisaged.           Over the past decades, especially after the passing of the great man, questions and doubts of the JLH enthusiasts and builders were answered largely by a dedicated few, who them...
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The JLH Gateway to Class-A :: 9

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Variations on the Classic Theme           In the history of DIY audio, no other amplifier has achieved such cult status and spawned so many variations as the Classic JLH has -- at least not to my knowledge. The tribe of upstarts aiming to upstage JLH, a "forgotten designer from the glass age", has been too many in the last fifty years plus; but we may safely ignore/forget them, as not even one such 'design' (mostly cobbled up in a circuit simulator, which to most of them was nothing more than an exotic toy!) has had any acceptance or has managed to survive in the chaotic hobby world.           On the other hand, devoted "JLH-ers" like Geoff Moss have made sterling contributions to the JLH legacy and his philosophy of design. We may also consider with respect the countless "tweakers and modders" who have attempted in their own way to adapt the classic JLH design to their times, with the components available at the time, and who ...
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The JLH Gateway to Class-A :: 8

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Following in the Master's Footprints           The audio world, as most of us know and admit, is peopled largely by "itchy fingers", and the JLH Classic too did not escape their 'itchy-bitchy' labours. While quite a few of these tweaks/mods could be classed with the proverbial exercise of transforming a horse into an a** ...oops! donkey, many did indeed add to the elegance in performance and the simple topology of the famous little amplifier. What astounds many is the fact that this labour of love is continuing to this very day as is borne out by that marathon thread in DIYAUDIO on the JLH amplifier (nearing 500 pages and 10,000 posts) -- truly a testament to the timeless appeal of the Master's design.           It is probably in the present century young designers, who grew up in the world of Circuit Simulators and theoretical explorations of the "what-if" kind, wanted to "play" with the classic design. They little realized it...
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