Searching for a Unicorn Part 1: Measuring Voltage Regulator Ripple Rejection

In this article Brian Lowe shares a fascinating journey in his search for a "Unicorn" that is measuring voltage regulator ripple rejection - or power supply rejection ratio (PSRR). Lowe is the founder and principle engineer at Belleson, LLC, and he has devoted a lot of time to this fascinating "quest." This article was originally published in audioXpress, May 2019.

This Test Bench characterizes the Bianco 44CD-K from SB Audience, a new brand from SB Acoustics. The FEA-optimized ferrite compression driver arrived with its H-250 90° × 90° exponential horn. The SB Audience 44CD-K features a 44 mm (1.75”) diameter voice coil wound with round copper wire on a high-temperature Kapton non-conducting former, driving a single piece Kapton diaphragm and surround. This article was originally published in Voice Coil, May 2019.

The Celestion CDX1-1732 is driven by a 44 mm (1.75") diameter voice coil wound with edge-wound copper-clad aluminum wire on a high-temperature fiberglass non-conducting former driving a single piece polyimide diaphragm and surround. For this Test Bench, Celestion supplied its 1” H1-7050 “No Bell” elastomer (plastic rubber) damped cast aluminum 70° × 50° exponential flare horn. This article was originally published in Voice Coil, May 2019.

In the first part of this article, Mike Klasco discussed the contribution of the enclosure on perceived overall product quality as well as sonic clarity. This second part of the article looks closely at material testing, evaluation and manufacturability, and other more recent approaches to enclosure materials, including Thermosets and Thermoplastics, Bulk-Molded and Sheet-Molded Thermosets. This article was originally published in Voice Coil, May 2019.

For the May 2019 "Glass Audio" special edition, audioXpress asked Erik Owen to share with us his experience with the new Nu:Tekt HA-K1 “Tube” headphone amplifier using the novel Korg Nutube 6P1 device. This interesting headphone amplifier is sold as a kit for $199, it's relatively easy to assemble, and - more interestingly - makes for a practical way to actually induce some of the magic of tubes in a relatively portable configuration.

Voice Coil May 2019 features an overview of Asian speaker manufacturing outside of China, with a detail portrait country by country. Mike Klasco reports on Loudspeaker Enclosure Materials, focusing on new and improved material alternatives. James Croft reviews a new patented design from Harman to improve reproduction in boundary-coupled systems, and in Test Bench, Vance Dickason characterizes two new 1” compression drivers, one from Celestion, and another from SB Audience, a new brand from SB Acoustics targeting pro audio applications. All this and the usual Industry Watch updates, now ready to download!

For audioXpress May 2019 -Glass Audio Special - we’ve put together a very strong edition, with some of best tube experts sharing a series of DIY projects for all skill levels, from restoration projects to new amplifiers, preamps, and headphone amps. We review the Nu:Tekt HA-K1 headphone amplifier using the novel Korg Nutube 6P1 device, and interview the founder of Parks Audio. We go deep on measuring voltage regulator ripple rejection and we even look at square-wave testing. All inside audioXpress May 2019!