audioXpress November 2023 Takes You to the Edge of Audio Development

audioXpress November 2023 offers an exclusive in-depth report on optical MEMS microphone technology from sensiBel, and understand how microphones can impact active noise cancellation performance. Learn how a new ADC Hybrid Gain Control IC enables smooth microphone preamp gain changes, and how to use DSP for hearing enhancement applications. Explore a Motion Feedback (MFB) approach enabling effective active desktop subwoofers, and recap on a century of Home Loudspeaker Development.

It's time for the Glass Audio/Tube Focus edition of audioXpress. In this issue, Michael Boele shares his long-term review of a pair of 2021 new production Western Electric 300Bs, Merlin Blencowe explains how to add Bluetooth to a Tube Amp, and Alan Kimmel introduces us to the possibilities of the Pentriode. There's also a Market Update report on vinyl sales and the latest trends in turntables and cartridges, as well as a review by Stuart Yaniger of the latest Orchard Audio Starkrimson Stereo Ultra GaN-based amplifier.

A few years ago, Jan Didden designed a high-voltage delay unit and shared its details in a 2019 audioXpress article. Many people built it and like it, but others said that it would be totally unnecessary. As so often happens in audio, arguments pro and con raged without a clear resolution. So Didden thought this was something he needed to get his head around. He found several sources, which he thought were credible, and this article is the result of his investigations, fed by those sources. This article was originally published in audioXpress, August 2020.

In this article, Bill Reeve explains how to drive tube heaters with a constant current to lengthen the life of your vacuum tubes. As he explains, obviously, the best way to extend your amplifier’s vacuum tube life is to never turn it on. Some would say that the second best thing you can do is to never turn it off. The third and fourth options may be to gently turn on the tube heaters and not leave the B+ voltage on when the heater voltages are off. This article was originally published in audioXpress, May 2014.