Special Feature: Accessible Pentode and Beam Power Tube Power Amplifier Projects
This feature presents a collection of power amplifiers for readers who are ready to move beyond “beginner-level” projects. The amplifiers use readily available components, while incorporating thoughtful design concepts and circuit refinements.
Projects include a hybrid amplifier using a differential line driver IC, a simple and easy-to-adjust fully direct-coupled amplifier, and two amplifiers using horizontal deflection output tubes. The articles also cover techniques for producing clean, attractive chassis work, as well as methods for estimating plate characteristics from limited tube data. Take on one of these projects this summer.
- EL84 Push-Pull Hybrid Power Amplifier
Uses a differential line driver IC, with tubes employed only in the output stage and no capacitors in the signal path — Yasuo Iwamura
- 6CA7/EL34 Single-Ended Fully Direct-Coupled Power Amplifier
A dual-power-supply design using widely available components — Susumu Soya
- 12G-B3 Push-Pull Power Amplifier
A 21 W amplifier using Japanese-made horizontal deflection output tubes for which published data is limited — Kosuke Ueno
- 25E5 Push-Pull Power Amplifier
An 11 W amplifier using triode-connected horizontal deflection output tubes — Masaru Nagashima
Original Sound System Projects
- 6P1-SCT4013DR & 396A-SCT4013DR Hybrid Power Amplifier
Battery-driven, super high-power output of 136 W into 8 Ω — Akihiko Kaneda
- Computer-Aided Audio Amplifier Design and Construction, Part 65
Building a multi-amplifier system, Part 5 — Heisuke Ikeda
- Experiments in Field-Coil Conversion of the Diatone P-610, Final Part
Building an optimized system for a modified driver: driver improvements and a reassessment of the field-coil power supply — Kosuke Ueno
- Designing and Building Compact Loudspeakers, Part 200
Pursuing a high-efficiency, high-sound-quality system — Takahisa Ozawa
Audio Technology
- New York–Tokyo Audio Correspondence: The Wheel of Time, No. 5
The Ojas kO-R2 and 1506 Multicellular Horns: A contemporary approach to large-format horn design — Devon Turnbull
- The History of Audio Manufacturers as Seen Through the Evolution of Their Hardware, Part 109
Luxman’s 90th to 100th anniversary years, Part 4, Final Part: Solid-state separate amplifiers and clean power supplies — Isao Shibasaki
- Understanding True Performance Through Measured Data
Measuring vacuum tube characteristic curves, Part 6: Dynamic coupling with the DA42 — Masaki Kubo
- Audio Equipment Repair Diary, Part 28
From junk item to practical component: maintenance of the Nakamichi LX-3 and TEAC V-2RX cassette decks, plus calibration of a wow and flutter meter — Hideyuki Sakai
MJ Zoom-Up
- Audio-Technica AT-MCD1 MC cartridge with an integrated diamond stylus tip and cantilever
- Denon DP-500BT belt-drive turntable with built-in phono EQ and Bluetooth
- Tecnologia e Cuore DS-TC52B two-way speaker system
- Epos ES-7N two-way speaker system
- Syntec NDT-075100PS balanced-transmission isolation power transformer
MJ Report
- Tiglon TPL-3000L-WT LAN cable
- Waecho Acoustics JUST PUT CORNER corner acoustic diffusion panel
- New Product News
Music, Acoustic Spaces, and Pro Audio
- The Dream of the Hi-Fi Listening Room, No. 656
A listening room that achieves a natural acoustic space through power-supply and vibration-control measures — At the home of Tadashi Higuchi, Sagamihara, Kanagawa
- The Dream of the Hi-Fi Listening Room, No. 657
An audio system that draws new insight from 1930s cinema sound equipment — Oswalds Mill Audio — MJ Editorial Department
- Improving the Listening Environment and Sound Quality with Ease
A guide to using acoustic measurement apps for smartphones — Yutaka Masaki
- Building High-Performance, High-Sound-Quality Loudspeakers Using the Latest Measurement and Design Techniques, Part 40
Improving room acoustics, Part 1: Understanding the fundamentals — Kohei Suzuki
Audio and Software Guide
- The Future of Audio Style
The latest trends in Astell&Kern DAPs — Takashi Iwai
- Classical New Release Reviews
Naoya Hirabayashi, Ikuo Tsunoda, and Chitake Inoue
- Jazz, Rock, and Pop New Release Reviews
Masahiro Imai, Yoshinobu Morita, and Mitsugu Kobayashi
- Classic Recordings and Legendary Performances Beyond Audio, Part 185
Captivated by variable equalizers — Naoya Hirabayashi
- Into the Forest of Cinema in Search of Masterpieces, Nos. 208/209
Masashi Yanagisawa
Readers’ Pages
- The 8th MJ Audio Festival
1,200 audio fans gather for the event — MJ Editorial Department
- Commemorating the completion of the 100 Years of Loudspeaker Technology series
- Interview with Tamon Saeki
Tracing the history of loudspeaker development — MJ Editorial Department
- Ojas’s latest system exhibition and vacuum tube amplifier building workshop — MJ Editorial Department
- MJ Book Guide
100 Years of Loudspeaker Technology V: Final Volume — The decisive factors in sound creation for loudspeaker systems — Isao Shibasaki
- MJ note information updates
- Audio Information