■ Feature：Three models of phono equalizers for optical cartridges
Playback using optical cartridges with an LED light source and photodiode detection—now attracting attention as a breakthrough in analog reproduction—requires a dedicated phono equalizer.
At first, users had no choice but to rely on commercial products, but thanks to the research of pioneers led by Akihiko Kaneda, the groundwork has gradually been laid for viable amateur DIY construction.
In this feature, we present three DIY examples of vacuum-tube phono equalizer amplifiers for optical cartridges, highlighting the current technical state of the art.
●Challenging the Latest Devices with Vacuum Tube Technology: Dedicated Phono Equalizer Amplifier for Optical Cartridge DS-E3 - Hiroshi Ueno ●Equalizer Amplifier for Optical Cartridges: WE 396A, Op-amp, Balanced Output IC, and Ultra-Low Noise Power Supply Module - Yasuo Iwamura ●Dual Cartridge Vacuum Tube Preamplifier: Compatible with Optical and MC Cartridges, 420A First Stage Differential Amplifier + 396A SEPP Output Stage - Akihiko Kaneda ●Audio Test of 3 Builder-Made Phono Equalizers for Optical Cartridges - Takashi Iwai ●Latest List of Optical Cartridges & Phono Equalizers
■ Original sound system production
●Stable operation achieved with a dual power supply system: 8045G single direct-coupled power amplifier - Susumu Soya ●Russian-made direct-heated triode driven by cathode follower, 6.5W output in Class A2 operation: SV811-10 single power amplifier - Masaru Nagashima ●12AX7, 12AU7 multi-function preamplifier with phono equalizer, tone control, line output, and headphone output - Kazutomo Kobayashi ●Building the optimal system for modified units: Experiment on excitation of Diatone P-610 [Part 2] Construction of enclosure and excitation power supply - Hiroshi Ueno ●Audio amplifier design and construction support using a PC [Part 64] Construction of a multi-amplifier system (4) - Heisuke Ikeda ●Manufacturing high-performance, high-quality speakers using the latest measurement and design [Part 39] Construction of a small 2-way speaker using SEAS magnesium woofer (Conclusion) Measurement and exterior finishing - Kohei Suzuki ●Designing and manufacturing a small speaker aiming for a high-efficiency, high-quality system [Part 199] -Takahisa Ozawa
■ Audio Technology
●Soul Note: Circuit Technology of Series 1/Series 2 ver.2 - Isao Shibasaki ●The History of Audio Manufacturers as Seen Through Hardware Changes [Part 108] Luxman's 90-100 Years of Progress (3) Semiconductor Integrated Amplifiers - Isao Shibasaki ●Knowing True Characteristics Through Actual Measurement Data Measuring the Characteristic Curve of Vacuum Tubes (5) Characteristics of 4-65A Triode Connection - Masaki Kubo ●Reviving from Junk to Practical Equipment Audio Equipment Repair Diary [Part 27] Maintenance of Yamaha FM/AM Tuner T-7 - Hideyuki Sakai
■ MJ Best Audio Components
● Soul Note A-1 ver.2 Integrated Amplifier ● Fundamental aina Integrated Amplifier ● Fidelix ARIETTA 2-Way Speaker System ● Yamamoto Sound Craft BX-70-LE8T Enclosure for LE8T ● Soul Note D-1 ver.2 D/A Converter
and more
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MJ Radio and Experiments April 2026 Spring Issue | Seibundo Shinkosha Co., Ltd. (seibundo-shinkosha.net)