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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12 point checklist for anyone using opamps in an audio design

Opamp User Guide V1.0.pdf

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X-Altra Mini One Line Preamplifier

The X-Altra Mini One is a simple line preamplifer based on the National Semiconductor LM4562 (also known as the LME49720) that I built around 2008 and which served me well until about 2014 when it was replaced with newer more sophisticated designs. Nevertheless, this simple preamp sounded very good, and thanks to the LM4562 (which […]

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Opamp Noise Visualizer

This Excel spread sheet tool was developed from one by Steve Hagman (www.AnalogHome.com) and allows en and ien data for up to 7 opamps to be compared.  When using the tool, make sure you enter comparable data – so for example,  always use the same frequency to make the comparison.  I normally use 1 kHz […]

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Ovation SCA-1: A high performance fully balanced line pre-amplifier

  Originally published in 2010 Here is the result of my investigation in to a fully balanced high performance, low distortion line pre-amp, the ‘Ovation’ Stereo Control Amplifier¬†One’. I drew some inspiration for this project after reading about the TEAC Esoteric line preamp, which is also based on the TI PGA2320, and received rave reviews […]

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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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