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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Baxandall’s Original Tone Control Article from Wireless World 1952

This article was published in October of 1952, when Baxandall was 31 years old, the design having already won him a prize 2 years earlier in a competition. His design basically relegated other tone control circuits to the scrap heap, although cheap passive, or non-inverting circuits still persisted well into the 1980’s, especially in low […]

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OPEX-1: A Discrete OPAMP for Audio

This design showcases a discrete opamp for audio applications.¬† It features very low noise, low distortion and a class A output stage that will deliver 1ppm distortion into¬† a 600 Ohm load at 12 V peak.   OPEX-1 Discrete Opamp

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