Audio Electronics - Cascodes, Folded Cascodes, and Current Mirrors (Part 3)

For those readers following the fascinating article series by Morty Tarr on "Cascodes, Folded Cascodes, and Current Mirrors," this final article in the series contains an additional section with important aspects of amplifier design. In the first two parts of this article series, Tarr discussed the technical merits of cascodes and related circuits. This useful addendum covers a simple test circuit for matching FET devices, the fascinating story of the Blowtorch Line Stage design, and additional notes on inverting and non-inverting amplifier stages and integrators. This article was originally published in audioXpress, December 2021.

In Part 1 of this three-part article about circuit topologies that are used to provide specific functions for an amplifier design, the author discussed cascodes and folded cascodes. In this Part 2, he focuses on current mirrors and line stages. As the author writes, “As designers, we have many devices to choose from. Some devices are ideally suited to certain tasks. Other tasks require performance that is difficult to achieve. While many excellent devices exist today, ideal devices do not exist, except maybe in Spice simulations.” This article was originally published in audioXpress, October 2021.

For this audio electronics article, Morty Tarr wrote a fascinating exploration of circuit topologies that are used to provide specific functions for an amplifier design. Cascodes, folded cascodes, and current mirrors are some of these topologies, intended to improve the performance of the devices, but which also add complications. In the first of a three-part series, the author discusses cascodes and folded cascodes, useful to improve high-frequency response and device linearity.

Luxman announced a new stereo power amplifier that introduces the new LUXMAN Integrated Feedback Engine System (LIFES1.0) circuit. The new refined audio design is said to achieve the ideal balance between low distortion and effortless musicality using 3-stage Darlington equipped quadruple paralleled push-pull output modules. The Luxman M-10X replaces the classic M-900u of 2013 and joins the acclaimed D-10X digital player as flagship models that anticipate the company’s 100th anniversary in 2025.

Arrow Electronics and Freelancer.com, the freelancing and crowdsourcing marketplace, announced the launch of ArrowPlus powered by Freelancer.com. The new platform allows companies and innovative technology creators to design and build hardware products through access to over half a million skilled electronic and electrical engineers. With the new platform, Arrow enables collaboration on a large volume of projects, from established companies, matching engineering services within 24 hours powered by Freelancer.

Linear Audio Volume 11 is now available and includes excellent tutorials by Gary Galo, Hans Polak, Giovanni Stochino, Michael Kiwanuka, Guido Tent and Burkhard Vogel; articles on Circuit Design by Dimitri Danyuk and Douglas Self; articles on Room Acoustics by Hannes Allmaier and Bill Waslo, book reviews, and much more.

Now available, Linear Audio Volume 10 is the 11th issue of Jan Didden’s series of printed bookzines dedicated to technical audio and perception. It features a great team of contributing authors and a strong collection of enjoyable articles, with a diversified and refreshingly divergent collection of personal takes on great audio topics.