You Can DIY! X-Altra MC-MM RIAA EQ Preamp - Part 1

In this DIY project, Andrew C. Russell proposes the X-Altra, a highly refined Moving Coil/Moving Magnet RIAA EQ Preamplifier. This high-performance phono equalizer features an ultra-low noise LSK389B JFET from Linear Systems in the MM front end with switchable gain and resistive loading. This article was originally published in audioXpress, February 2021.

The driver to be characterized in this article is Wavecor’s FR070WA05, a 2.75" full-range driver with a black anodized aluminum cone, built on a proprietary injection-molded polymer four-spoke frame. Like most contemporary drivers, the area below the spider mounting shelf is totally open for increased cooling. Powering the cone assembly is a dual neodymium motor. This article was originally published in Voice Coil, February 2021.

The AUGWL0006-JN01 is a new 2.25" woofer from Eastech’s Punktkilde lineup. With a depth of 7/8", the AUGWL0006-JN01 is part of the Ultra-Thin Series. The feature set is rather clever, using a black anodized aluminum cone assembly and dust cap, suspended with a NBR surround. A 25mm round foam surround supplies the additional compliance, and a large 35.5mm diameter under hung voice coil rides inside a double set of neodymium ring magnets. This article was originally published in Voice Coil, February 2021.

In this article for audioXpress, Brent Butterworth reviews the Widex Moment mRIC RD hearing aids. In a first for his career as a regular reviewer of headphones, hi-fi components, and other consumer audio products, Butterworth spent considerable time with the Widex Moment, one of the newest entries in the high-tech hearing aid category. His review objectively looks at the differences and similarities in the critical sound experience.This article was originally published in audioXpress, February 2021.

Nureva's Microphone Mist technology is a patented concept of generating thousands of virtual microphones in a 3D space. This article explains why this can be the alternative approach to the status quo of physical microphones and beamformer systems to create perfect audio conferencing solutions in any type of room and with multiple users. This article was originally published in audioXpress, February 2021.

The February 2021 edition of Voice Coil offers an overview of the Cone Industry in 2021, with an updated directory of loudspeaker cone, diaphragms and suppliers of relevant materials and components. Next up, James Croft reviews an interesting patent for a "Directional Loudspeaker," claimed by Dutch & Dutch BV, and Vance Dickason focuses his measurements on two small-sized drivers, typical of today's most popular consumer products. The first in Test Bench is the Wavecor FR070WA05, a 2.75" aluminum cone full-range driver, and the second is the AUGWL0006-JN01, a new 2.25" woofer from Eastech’s Punktkilde lineup.

audioXpress February 2021 explains why Microphones have gained Essential Status, and how microphones have a foundational contribution to voice front-ends. Erica Yorga details how Thousands of Virtual Microphones can solve audio conferencing challenges, and Mike Meechan explains how to design high-performance microphone preamplifiers. Brent Butterworth reviews the Widex Moment mRIC RD hearing aids to understand the differences and similarities in the critical sound experience. Michael Steffes explains how to increase the output current for an audio op-amp, and Andrew C. Russell details the X-Altra, a high-performance MC/MM phono equalizer DIY project. Now available in print and digital.