The Theory of TIM – Matti Otala

Matti Otala  follows up on earlier research on the subject of TIM. The Theory of TIM Matti Otala

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Review of Bob Cordell’s Book ‘Designing Audio Power Amplifiers’

‘Designing Audio Power Amplifiers’ by Bob Cordell  – Reviewed by Andrew C. Russell in 2011 Bob Cordell (on the right) pictured with Jan Didden, publisher of ‘Linear Audio’ After a 25 year hiatus from electronics, I returned about 6 years ago (i.e. 2005) to linear design not as a professional but as a hobbyist. Earlier […]

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Barney Oliver: Crossover Distortion in Class B Audio Amplifiers

This is the famous analysis of class B amplifier cross-over distortion by the then head of HP Reasearch Labs, Dr. Barney Oliver,  published in the February 1971 edition of the HP Journal.  The  bias current Iq for a class B emitter follower amplifier is shown to be approximately  Iq = .026/(Re+re+(rb/hFE)). In practice,  – the […]

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Output Coupling Inductors

Inductors on the output of an amplifer are used to isolate the amplifer from capacitive loads at HF and ensure stability.  There has been quite some debate on DIYaudio.com as to whether they are audible, necessary, or just the result of designers being overly cautious.  Some very well known designers in the field have decided against using […]

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The Monolithic Op-Amp: A Tutorial Study

This was an invited paper at the ISSCC in 1974 by James Solomon, who at the time worked for National Semiconductor (acquired in 2011 by TI). Those were heady days in semiconductors, with major process and circuit design breakthroughs taking place at breakneck speed. The general purpose microprocessors’  pivotal role in powering the Apple II […]

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Feedback Analysis by Marshal Leach

Here is a short write up by Marshal Leach (RIP) on feedback analysis.   fdbkamps

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