audioXpress May 2025 Brings the Best in DIY Audio with Tubes

This year’s special Glass Audio issue of audioXpress includes interesting explorations such as the Ultra-Linear Power Amplifier by Rudolf Moers, Micro Details in Push-Pull Output Transformers by Hans Polak, Getting Less Gain From Tubes by Merlin Blencowe, and the Type 3 Mu Stage Breakthrough by Alan Kimmel. This issue also includes two speaker designs from Ben (Wolf) Shaffer and Ken Bird, an article about the intriguing return of 78 rpm records, and Paul Marchese’s Part 2 of his insightful Primer on Class-D Amplifiers. Richard Honeycutt shares how he learned to DIY with Tubes.

This DIY-focused article introduces the Pentriode, a concept to explore the familiar idea of connecting commonly available pentode tubes as triodes, creating a circuit that excels in linearity. The Pentriode is formed by making one simple change to connect the screen grid to the cathode of a cathode follower. The article proposes different possible approaches, including for a mu stage, a design that the author previously wrote about for audioXpress. This article was originally published in audioXpress, May 2022.

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.

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!