All items tagged with tube amplifiers (91)

Micro Details in Push-Pull Output Transformers

September 4, 2025 by Hans Polak

Micro Details in Push-Pull Output Transformers

Having stumbled upon some reports on the loss of micro details due to a collapse of permeability in output transformers, and being of an inquiring nature, Hans Polak decided to have a detailed look. This supposed phenomenon would be detected with push-pull (PP) tube amplifiers with output transformers at low levels, near our auditory threshold. For this investigation he focused on the output transformer (OPT) in isolation.

Ray Tubes Expands Range with Select 12AU7 and Core 12AU7 Vacuum Tubes

August 4, 2025 by Joao Martins

Ray Tubes Expands Range with Select 12AU7 and Core 12AU7 Vacuum Tubes

Ray Tubes announced new-production 12AU7 tubes in both its Core and Select Collections. With this addition, Ray Tubes is now supplying the most common vacuum tubes, including the 12AU7, 12AX7, EL34, 6SN7, KT88, and 300B, all available through its network of retail and brand partners. All products from Ray Tubes are designed and tested specifically for audio applications and come with a one-year warranty, which is a great assurance compared to the risks of buying New-Old-Stock items.

You Can DIY! Type 3 Mu Stage Breakthrough

July 16, 2025 by Alan Kimmel

You Can DIY! Type 3 Mu Stage Breakthrough

The original Mu Stage project, published in Glass Audio in 1993, remains a popular build, serving the author's purpose to "combat listener fatigue." His Type 2 Mu Stage, published by audioXpress in 2019, introduced a streamlined version with added capabilities. Now, the new Type 3 Mu Stage resulted in what the author believes to be a breakthrough, improving the realistic reproduction of music. This latest iteration of the circuit was prototyped by Kim Bond, an enthusiastic builder of the previous Mu Stages.

Book Review: Zoran M. Dukic’s High End Tube Amplifiers Designer Tool Box

May 7, 2025 by Jan Didden

Book Review: Zoran M. Dukic’s High End Tube Amplifiers Designer Tool Box

This extensive, 428-page, self-published hardcover book, is much more than another publication on tube amplifiers. As Jan Didden discovered, this book contains all the knowledge needed to check how an input low-pass filter must be dimensioned, how to investigate the different resistor types and their properties, capacitor types, which tubes to use, how to bias them, and construct the load lines, and even how to design low-noise power supplies. A one-stop resource for tube-based audio power amplifiers, and clearly a work of love!

Expand Your Audio Development Skills with audioXpress March 2025

February 12, 2025 by audioXpress Staff

Expand Your Audio Development Skills with audioXpress March 2025

audioXpress March 2025, focused on Test and Measurement and audio electronics, explains how to test Power Amplifiers, and how to measure HDMI Audio. Explore the possibilities of George Ntanavaras' SL-100 Sound Level Adjuster and Tom Perazella's Reinforced Speaker Protection solution. Read the interview with Mike Engelhardt, explaining everything about audio THD with QPSICE circuit simulation. Brian Lowe concludes its article on Op-Amp for Phono Preamps, and much more.

Find All the Cutting-Edge Audio Knowledge in audioXpress February 2025

January 13, 2025 by audioXpress Staff

Find All the Cutting-Edge Audio Knowledge in audioXpress February 2025

Read the Market Update on MEMS microphones, Shure’s valuable perspective about Wireless Multichannel Audio Systems (WMAS) technology, and a review of the extraordinary Eigenmike em64 Ambisonics microphone. Brent Butterworth reviews the new Sony MDR-M1 headphones, and Alex Bonnet and Eric Benhaim (Orosound) explain how to leverage ANC in open-ear designs. Brian Lowe (Belleson) shares his Top Amp design for phono preamps, Douglas Self reveals more op-amp distortion tests, and Richard Honeycutt revisits the legendary Dynaco ST-70 and ST-70 II tube power amps.

Lessons in Life. A Tribute to Peter Janis (1958-2024)

August 15, 2024 by Joao Martins

Lessons in Life. A Tribute to Peter Janis (1958-2024)

Last week I received the very sad news about the passing of Peter Janis, the founder of Radial Engineering. I always admired Radial Engineering for its ability to always surprise and delight with inventive and practical solutions that solved real issues for musicians and audio engineers, in many fields of application. Every time I had the chance to meet Peter Janis at any trade show around the world, I would find that he enjoyed as much to surprise and delight with those inventive and practical solutions.

Marshall Celebrates Celestion's 100th Anniversary With Limited Edition Amp

July 15, 2024 by audioXpress Staff

Marshall Celebrates Celestion's 100th Anniversary With Limited Edition Amp

To mark Celestion speakers' 100th anniversary, Marshall has given the Studio JTM amp a masterful redesign, featuring the introduction of an artisanal 12-inch speaker. Recalling the legacy and sound of Celestion’s first speakers built for electric guitars in the late 50s and early 60’s, the Celestion 100 amp is a display of the long-standing collaboration between the two legendary British companies. This collector’s piece has been handcrafted in the UK and is available for a limited run of just 100 units worldwide.

Centrance Brings AMPmini Class A Headphone Amp to High End Munich 2024

April 29, 2024 by Joao Martins

Centrance Brings AMPmini Class A Headphone Amp to High End Munich 2024

Announced in 2023 and already demonstrated at some of the recent CanJam events, Centrance is now closer to shipping its latest AMPmini, an 8-Watt compact headphone amplifier with a variable tube preamp that allows choosing the amount of tube tone to taste. This unique design perfectly complements the company's DACmini 2 balanced desktop DAC/amp, both featuring a compact aluminum chassis that is designed to stack with the Apple Mac mini or the new Mac Studio, to create a complete premium sound solution for the modern desktop.

audioXpress May 2024 Glass Audio Special Issue Now Available

April 12, 2024 by audioXpress Staff

audioXpress May 2024 Glass Audio Special Issue Now Available

In the 2024 Glass Audio Special issue there’s Menno van der Veen’s TubeSociety TS-2022-OTL hybrid amplifier, and a Low-Feedback Triode Amplifier With Zero Output Impedance (ZOI) as DIY projects, designed by Tim Mellow and Peter Farrow. More great audio electronic articles by Rudolf Moers, Christopher Paul, and Dimitri Danyuk. Read about sustainable acoustical absorption, the Pure Acourate Sound Project, and The Neurochrome Story. And Andrew C. Russell concludes his High-Performance 60-Watt Class A Amplifier project.

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