You Can DIY!: Repurposing an Old Preamp for Line-Level Duty

This modification and restoration article shows how to preserve the best features of unused tube equipment. The article describes a tube preamplifier that the author wanted to position at the input to his home power amplifier, eliminating the need to adjust his 1972 McIntosh MX10 tuner and 240 power amplifier’s volume high when he wants to fill his home with music. In this case, an old Shure Model 65 stereo conversion preamplifier using two dual-triode 12AX7 tubes provided an excellent platform for the project. This article was originally published in audioXpress, May 2020.

In this DIY project, Andrew C. Russell proposes the X-Altra, a highly refined Moving Coil/Moving Magnet RIAA EQ Preamplifier. This high-performance phono equalizer features an ultra-low noise LSK389B JFET from Linear Systems in the MM front end with switchable gain and resistive loading. This article was originally published in audioXpress, February 2021.

In this article, Jack Elliano the founder and principal designer behind Electra-Print Audio, details a simple but very interesting concept of a line amplifier using step-up transformers plus a variable gain control, offering usable results from low impedance sources. The preamplifier project uses Electra-Print handcrafted transformers, which the company manufactures for its own high-fidelity tube audio components, directly from its home base in Las Vegas, NV. This article was originally published in audioXpress, January 2005.

A perfect companion for your hifi system at home or in your studio was the way Sonosax introduced the idea for the new SX-DD2. Unveiled almost 3 years ago as an "upcoming project," when Sonosax celebrated its 40th anniversary, the SX-DD2 is a universal, mains powered, studio-quality preamplifier, capable of processing virtually any audio signal, digital or analog, even the output of a turntable. Now, Jacques Sax confirms the new design will start shipping in Spring 2021.

Harman's Mark Levinson unveiled an expanded line of 5000 series products. Four new products that maintain the highest level of engineering, design, and passion for detail the brand is known for, but also reflect an attempt to reach to new generations of consumers and increase awareness for high end audio. Two source players and two flagship separates that expand the philosophy introduced with the launch of the Nº 5802 and Nº 5805 integrated amplifiers, and aim to reinvigorate the luxury audio experience.

New York-based Mytek Digital revealed the details on its new Empire DAC/Streamer/Preamplifier, supposed to be the flagship of a new Empire series of very high-end audio products. As the company describes, this is an "all out" assault on the state-of-the-art, establishing Mytek as a top echelon player in the high-performance audio arena. The Streamer will be “Powered by Roon OS” and features an internal Roon Core that can drive both the ultra-high performance Empire DAC and external Roon endpoints.

audioXpress July 2020 is now available, and there's a quiet revolution happening in audio amplification. Essentially it is the direct result of strong innovation in Class-D technology, with incremental improvements introduced on multiple fronts. In this month's Market Update, J. Martins details a few of the "Class-D Products Getting Smarter" and then Stuart Yaniger discusses Class-D amplifiers from two of those companies: Purifi Audio and Orchard Audio. Also, Ward Maas details his visit to Purifi Audio. Dimitri Danyuk shares his "Fully Balanced Transconductance Preamplifier" project, Roger Russell is "Hunting the Elusive Transient," and Ed Simon concludes his "Powering Your Circuits" series. And there's much more valuable content in this edition. Download or view your issue online now.

Described as Radial's biggest product announcement in years (certainly since the company's acquisition in January 2018,) the HDI, Radial's new flagship DI Box is now shipping. Shown in prototype form at AES 2019 in NY, and officially announced at NAMM 2020 in January, the HDI is the answer to a question Radial put to in-house engineer "Hutch" Hutchinson: "If you could design any type of DI box you wanted, what would it look and sound like?"

Audio Research (ARC) announce important updates to its highest-performance tube phono stage, the Reference Phono 3 Phono Preamplifier with the launch of the Reference Phono 3SE. Following the launch of the recent Reference (REF) 6SE Line-Stage Preamplifier, ARC’s 50th Anniversary product line continues with a special edition update of the Ref Phono 3 Preamplifier. The REF Phono 3SE ($17,000 USD) replaces the REF Phono 3, introduced in 2016.

Schiit Audio announced the immediate availability of a pair of gaming-focused desktop DAC/Amps, Fulla 3 and Hel. Fulla 3 adds a versatile, high quality microphone input to its existing Fulla 2 DAC, while the retail price remains at $99. Hel adds much higher power output — 4x that of Fulla 3 — a stereo mic input with 24-bit ADC and front panel level control, as well as switchable input and gain, for $189. Two new products for a new class os users: high-end audio gamers!