It’s Here! The Glass Audio DIY Special audioXpress May 2015 Edition!

March 31 2015, 06:00
Yes! It seems like tubes get better with the years. Or at least our appreciation on how good tube-based circuits sound. And that’s the reason why more and more people cherish those NOS tubes and are increasingly ready to spend more money to get their hands on the best ones.
The Glass Audio Special edition is a tradition we have retained since the former title was merged with other magazines to become audioXpress. audioXpress still publishes tube-related articles, but we feel this is one of the highlights for our readers and it certainly is among our authors due to the amount of articles we receive — increasingly addressing applications outside of the typical high-end living-room stereos.
This month, we have an excellent article by Bruce Brown on “Updating the Bogen MO100A Amplifier.” The Bogen MO100A was originally designed for constant-voltage audio distribution, rated at 100-W. Although it is configurable to various installations, its output tubes are difficult to find. This article explains how to modify it using more common tubes.
And how about using an Antique Radio to Listen to Your Vintage Playlist? That’s the idea from Gregory L. Charvat in another DIY article detailing how to choose a vintage radio, perform a step-by-step restoration process, and make simple modifications so it can be plugged into any modern audio source.
Mark Driedger combined tubes with modern technology for an article published by audioXpress back in February 2015. This month, Driedger returns with “Extending the Arduino-Based Tube Power Amplifier Controller” in which he explains how to incorporate a bias meter, a temperature sensor, and a shut-down feature.
Of course, we needed to include a great amplifier project in our Glass Audio special and that’s precisely what Gerhard Haas does with his Push-Pull Triode Power Amplifier, using ECC 99 and ECC 832 Tubes. As Haas explains, this project will please tube enthusiasts who want a simple and convenient power amplifier to connect to high-efficiency loudspeakers; a small power amplifier to playback music from a digital player; or a small tube power amp for playing guitar.
For those who are less familiar with tube equipment, Gerhard Haas is also the author of “Why Tubes Sing and Crackle,” an article that hopes to answer why tubes sing and crackle, audio transformers hum, and many filaments brightly glow when switching on.
Naturally, our Hollow-State Electronics column on tubes contributes additional content to this month’s tube fest. Richard Honeycutt explores a few of the more well-known vintage pro tube power amplifier circuits including some great classics such as the Western Electric Model 92A, the RCA mi12246, the DuKane from the early 1960s, and the highly desirable Altec Lansing a340a.
Our May edition of audioXpress also signals the conclusion of our article series on Wireless Audio by João Martins. This month, we look at the impressive Microchip Wireless Audio Platform Portfolio, which offers an extensive portfolio of Bluetooth solutions, Kleernet technology for low-latency applications, and the JukeBlox Wi-Fi/Ethernet platform.
In their Headsets column, Mike Klasco and Steve Tatarunis look at ribbon planar headphones and why they continue to be some of the most desired audio products.
And there’s much more, including Ron Tipton’s article on Signal Dynamic and Loudness, the conclusion of Thomas Perazella’s subwoofer adventures, and a great interview with Richard Schram, the founder of Parasound.
As usual, your new issue of audioXpress is now available at
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