You Can DIY! The PR-3 - A High-Quality Stereo Preamplifier

For our readers who like to get hands-on with DIY projects, in this article George Ntanavaras describes the design and the construction of his PR-3 stereo analog preamplifier, offering three high-level unbalanced stereo inputs and two unbalanced stereo outputs. Most of the components for this design are contained on a single PCB. This article was originally published in audioXpress, January 2019.

In this article for audioXpress, Hans W. Gierlich, managing director of HEAD acoustics, explains how to test the different performance parameters of smart speakers and smart home devices under real-life conditions, how to deal with the challenges of optimizing systems for voice and audio quality, how to simulate environmental conditions, user behavior, and test the performance of the various functionalities. This article was originally published in audioXpress, January 2019.

This article is an interesting testimony from Piotr Szczechowiak, co-founder and COO at Zylia, a startup company from Poland, known for its ZM-1 spherical microphone array. The ZM-1 records and separates each instrument and vocals into a separate track using an innovative and patented recording sound-source separation technology, combining dedicated software and cloud processing. This article was published in audioXpress, January 2019

David Logvin explores the Lepai LP40PA ultra-compact amplifier, a versatile Class D common plate amp module with fully integrated Bluetooth 4.2 receiver and 3.5 mm stereo inputs, ideal for converting existing passive speakers into convenient portable and wireless units that can be placed anywhere. The Lepai LP40PA has plenty of power for a pair of bookshelf speakers as Logvin experimented. This article was originally published in audioXpress, January 2019.

Being primarily known as a pro sound driver OEM, with a great reputation for both guitar speakers and PA drivers, it may come as a surprise that this Eminence driver, the SD28, is a 1” soft dome tweeter — a staple of the home and car audio businesses. I should note however, that while Eminence has a rather large catalog of pro audio transducers, the company also produces drivers for home and car audio companies. This article was originally published in Voice Coil, January 2019

In this Test Bench I characterized the 475PB, a 1" compression driver from Radian Audio Engineering. The 475PB has a similar set of features as Radian’s 745PB. This includes a 1” throat diameter, a 134 mm × 19 mm ferrite magnet motor, and the most important feature—a proprietary processed and hardened aerospace-grade aluminum alloy diaphragm over a three-slit phase plug. This article was originally published in Voice Coil, January 2019.

For the January 2019 edition of Voice Coil magazine, Mike Klasco and Nora Wong have compiled a special Focus article on New Materials for Earphones and Headphones. For those looking to differentiate their new products, the two Menlo Scientific consultants provide a unique and valuable perspective on multiple possibilities and designs for drivers, materials for assemblies and enclosures, choices for headbands and ear cushions, signal processing, and even cables.

Voice Coil January 2019 is now available. This edition focuses on New Materials for Earphones and Headphones and also includes a valuable listing of Earphone and Headphone Manufacturers and a schedule of headphone-centric events for the year. In Acoustic Patents, James Croft looks at a new patent of a multilayer voice coil plate and flat speaker based on the same, while in this month's Test Bench Vance Dickason features a 1" compression driver from Radian Audio Engineering, and a 1" soft dome tweeter from Eminence. This is much more, now available in print and download.

The January 2019 (CES) edition of audioXpress has arrived. Read our Microphone Market Update, addressing the latest cutting-edge microphone technologies, and learn how Zylia created its ZM-1 spherical microphone array. Also in this edition, Joe D’Appolito explains how to address the equalization of closed-box subwoofers, Hans W. Gierlich writes about testing Smart Home Devices, David Logvin reviews the Lepai LP40PA plate amplifier, and George Ntanavaras describes a stereo analog preamplifier DIY project. Oh, and read Erik Owen's unique take on Rocky Mountain Audio Fest (RMAF) 2018.