Small Signal Audio Line Stage Buffer/Headphone Amplifier

This design, which I completed in 2010, takes an LM4562 and marries it to a hefty single ended class A output stage, which can be biased up for either 50 mA or 110 mA. The output stage is included in the global feedback network and can achieve 1 ppm at 20 kHz  into 600 Ohms […]

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Stochino Feed Forward Amplifier – Wireless World 1994

This article decribes a feed forward amplifier concept from Giovanni Stochino.  The design, while novel, is very complicated and delivers about 30 dB in distortion reduction. Stochino Feed Forward.pdf  For an altogether simpler alternative that acheives about 20 dB distortion reduction, take a look at AFEC (‘augmented feedback error correction’) elswhere on this site.

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Peter Walker’s ‘Current Dumping’ Amplifier from 1975

Peter Walker – Founder of Quad The famous Quad ‘Current Dumping’ amplifier launched in the mid 1970’s, and featured feed forward error correction that effectively removed the class B cross over distortion that plagues this type of output circuit structure. The design featured no adjustments in production, but the circuit components around the output (L2, […]

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Michael Kiwanuka: SOA Protection for Audio Power Amplifiers

Power Amplifiers, and especially bipolar output designs, require output stage  protection  in the event of a fault, or the presence of a heavy or highly reactive load.  Michael Kiwanuka explains the intricacies and the design methodology in his paper here  soaprot_12-03-2012

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Noise in Current Sources and Current Mirrors