Fresh From the Bench: Benchmark HPA4 Headphone/Line Amplifier

Gary Galo reviews the Benchmark HPA4, a reference headphone/line amplifier designed to deliver amplification of analog sources for audio enthusiasts, mixing and mastering engineers. Resulting from Benchmark’s collaboration with THX, the HPA4 features a THX-888 headphone amplifier for an output signal with high voltage, current, and and power complemented by low distortion, noise, and crosstalk. This article was published in audioXpress, November 2019.

For this edition of Test Bench we characterized the Punktkilde AUGDL0003-JN03, a 1” magnesium-lithium alloy dome tweeter. This transducer, from Eastech’s relatively new Punktkilde line of home hi-fi drivers built in China and designed in Denmark by Scan-Speak engineers, is a tweeter from its magnesium-lithium product line, which includes this AUGDL0003-JN03 tweeter plus 4” thru 8” magnesium-lithium alloy cone woofers. This article was originally published in Voice Coil, November 2019.

In this month’s Test Bench, we characterize Dayton Audio’s DMA80-4, a new 3” full-range line array/smart speaker driver. The Dayton Audio DMA80-4 is one of the transducers from the brand's new DMA Series, where DMA stands for Dual-Magnet Aluminum Cone and includes five models of full-range drivers, all with both 8 and 4 ohm versions. This article was originally published in Voice Coil, November 2019.

Anytime we need to login to the local Wi-Fi or pair with another Bluetooth device, we think, "There must be a better way to do this!" That's precisely one of the exciting possibilities for data-over-sound technology. This article explains what else we can do with it, and how it works. It also explores how data-over-sound can be realized in embedded scenarios, and how Chirp’s new technology, using the Arm Cortex-M4 and Cortex-M7 processors, can be implemented in connected products. This article was originally published in audioXpress, November 2019.

November 2019 marks Voice Coil’s 33rd year as an information resource for the loudspeaker industry. For this edition, Mike Klasco focuses on "Measurement Microphones: Today and Tomorrow," while Nora Wong provides another valuable updated directory of Test & Measurement Microphone manufacturers and suppliers. James Croft reviews a new coaxial loudspeaker assembly patent granted to Tymphany, while Vance Dickason characterizes the DMA80-4, a 3" full-range speaker from Dayton Audio, and the AUGDL0003-JN03, a 1” magnesium-lithium alloy dome tweeter from Eastech’s Punktkilde line.

The November 2019 edition of audioXpress is now available with a wide range of technical topics in audio electronics and design. We review the Benchmark LA4 Line Amplifier and the new Hooke Verse Bluetooth Binaural Recording Headphones. Jan Didden proposes an updated version of his High-Voltage Delay for Tube Amplifiers, and Thomas Zarbo, Jr. explains how to build his Tenacious Bass-8 Powered Subwoofer. And, learn more about Data-Over-Sound, MU amplification topologies, and Auverdion’s Aurora open-source DSP platform. Now available!

In this project for audioXpress magazine, Jan Didden offers a modern update on his original 2014 high-voltage delay design, which he built to complement tube amplifiers. The new unit needs no additional outside power, and allows setting the delay between 20 seconds and 254 seconds, which should cover all requirements. The article describes the complete project, and there's a DIY kit available at diyaudio.com. This article was originally published in audioXpress, November 2019.