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Articles

Welcome to our articles page, where you’ll find a wealth of information on everything audio-related. Our articles cover various topics that will appeal to audiophiles of all levels.

  • Amplifier History: The JBL SA-600

    Amplifier History: The JBL SA-600

    The beautifully styled JBL SA-600 amplifier was launched by the James B. Lansing company in 1966, and Bart Locanthi (the designer) wrote the  technical article (link further down) in January 1967.  This is one of the earliest – if not the earliest – example of a commercial  amplifier that addressed the potential for TIM/SID and…

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  • Solid State Feedback Amplifiers: A Short History

    “Why, sometimes I’ve believed as many as six impossible things before breakfast.” ― Lewis Carroll, Alice in Wonderland     A Future Without Feedback by Martin Colloms There is no mysticism in amplifier design, just serious science. —Andrey A. Danilov Introduction You will recall from the The Theory of TIM by Matti Otala elsewhere on this site,…

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  • Technical Requirements of Phono Preamplifiers by Tomlinson Holman

    The two articles below were written in the 1970’s, nearly a decade before the arrival of the CD and the ‘perfect sound forever’ claim made by Philips. There was a lot of focus on phono amplifier performance at the time which it could be argued was triggered by the arrival of very high performance turntables…

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  • Richard Lee’s Ultra-Low Noise MC Head Amp

    Richard Lee’s Ultra-Low Noise MC Head Amp

    This design was a development of Marshall Leach’s MC head-amp, from the 1970s, and to my knowledge, Richard Lee’s implementation presented here has not been bested in terms of noise – about 280pV/rt Hz in a well-implemented exemplar – other than in the Hifisonix X-Altra MC/MM Phono Preamplifier. Importantly, it requires only about 12mA current…

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  • My Loudspeakers

    My Loudspeakers

    I bought a pair of B&W 703’s in about 2003 and they travelled with me all around Asia when I worked there as an expat for ten years. These are big loudspeakers with fantastic bass and mid-range articulation. The treble may be a little forward for some, but for Jazz, big band and rock they…

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  • The Endless Semantic Debate: Current and Voltage Feedback Amplifiers

    It seems some are still agonizing over the ‘current feedback’ versus ‘voltage feedback’ definition.  Clearly a case of people wanting to continue to flog a horse that was laid to rest five decades ago during the heyday of the analog computer, or they simply fail to grasp the CFA concept. I suspect there are an…

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  • The Tale of Two Recordings

    I thought I’d share my thoughts with you on the sound of two LP’s I recently acquired.   Many of you will have heard of the term ‘sound wars’ which has been coined to describe the relentless increase in the use of  dynamic range compression in modern recordings, a development it could be argued from the…

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  • JLH 10 Watt Class A Amplifier

    This is a copy of the original John Linsley-Hood article that appeared in Wireless World in 1969. This design, almost 50 years old, is still built in its hundreds all over the world.  A quick root around on the web will show numerous kits, many of quite acceptable quality, emanating from China and Hong Kong.…

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  • Class A Buffering the Correct Way

    Here’s a simple way to force an opamp output stage to run in class A when used with a discrete buffer output stage – it takes just 1 resistor to provide a near constant current source load. Operating the opamp (and the output buffer stage) in class A dramatically reduces harmonics on the power rail…

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  • Hifisonix ‘Symphony’ Line Preamplifier

    Hifisonix ‘Symphony’ Line Preamplifier

    I designed and built this preamplifier while living in Taiwan a few years ago. The Symphony preamp features Baxandall tone controls, up to 7 inputs,  a class A 2 W headphone amplifier and a Goldpoint 24 position attenuator.  The write-up describes the design process and choices in some detail and my listening impressions: Part 1…

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