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About Jan Didden

Jan Didden has written for audioXpress since the 1970s and he is the magazine’s Technical Editor. He is retired following a career with the Netherlands Air Force and NATO. He worked in logistics, air defense, and information technology. Retirement has provided him with the time to finish all the audio projects that have piled up for decades. He sometimes writes about them on his website linearaudio.nl. Didden is also known as the publisher and managing editor of the twice-yearly bookzine Linear Audio, which he published until 2018. He is currently teaching audio electronics for enthusiast hobbyists and serious amateurs in the Belgian city of Hasselt. More information is available at linearaudio.net

All items written by Jan Didden

ICEpower Unveils Cutting-Edge ICC5 Audio IC for High-Performance Class D Amplifiers

November 13, 2023 by Jan Didden

ICEpower Unveils Cutting-Edge ICC5 Audio IC for High-Performance Class D Amplifiers

ICEpower A/S introduced the latest addition to its lineup of audio power solutions, the ICEpower ICC5. This audio integrated circuit (IC) boasts advanced technology, fast propagation delay, and support for up to a 220V supply voltage. As a high side and low side FET gate driver optimized for flexibility, the ICC5 enables high-fidelity sound with minimal noise and distortion, making it an ideal choice for reliable class D amplifier designs ranging from 25W to 4kW.

Bandwidth, Slew Rate and All That Jazz

October 20, 2023 by Jan Didden

Bandwidth, Slew Rate and All That Jazz

To reproduce an audio signal faithfully over the whole audio band, your circuit needs to have a bandwidth at least as large as the audio band. But that’s not the only requirement: your circuit needs to maintain that bandwidth from the lowest to the highest signal level. That’s where the crux lies: it is relatively easy to get a nice wide bandwidth for small signals, only to have it breakdown with high signal levels due to the dreaded slew rate limiting.

Audio Myths: Feedback Re-Entrant Distortion. Should We Worry?

September 14, 2023 by Jan Didden

Audio Myths: Feedback Re-Entrant Distortion. Should We Worry?

There are many aspects of negative feedback in audio that are the subject of continued discussion. Jan Didden continues to debunk more Audio Myths. This article addresses re-entrant distortion. The idea is that, since negative feedback sends some of the distorted output signal back to the input, this already-distorted signal would only get more distorted by going through the nonlinear amplifier, over and over again.

Audio Myths: Feedback Cannot Fix What Has Already Happened

August 24, 2023 by Jan Didden

Audio Myths: Feedback Cannot Fix What Has Already Happened

This article, originally published in The Audio Voice newsletter (#434), explores some practical experiments with Negative Feedback. "If I had a dollar for every time someone mentioned that negative feedback cannot work, because you cannot correct something after it happened, I would be a rich man," says Jan Didden. "Yes, it can be hard to get your head around feedback circuits for audio amplifiers. Yet, all it takes is to look around you," he adds.

Grimm Audio: Building the Dream

August 16, 2023 by Jan Didden

Grimm Audio: Building the Dream

audioXpress visited Grimm Audio in The Netherlands to learn more about the people behind this unique company, its products, and philosophy. There's nothing better to learn about product development than to visit an audio company and learn from its history and business journey. As a relatively young company, Grimm Audio has consistently put its mark on both the pro audio and hi-fi scene and Jan Didden shares what he learned about their unique in-house development philosophy. This article was originally published in audioXpress, July 2023.

Headphone Immersive Audio, Head Tracking, and Virtual Speakers

July 13, 2023 by Jan Didden

Headphone Immersive Audio, Head Tracking, and Virtual Speakers

What happens when you add Head-Tracking, Head Related Transfer Functions (HRTF), Room Impulse Responses (RIR), and Binaural Room Impulse Responses (BRIR)? Sharing his experience at the AES Europe 2023 Convention, held at Aalto University, Espoo, Helsinki, Finland (May 13 – 15), Jan Didden writes about listening to speakers on headphones and how good this is getting. How convincing is it? Very.

Book Review: Learning Audio Testing and Measurements

July 12, 2023 by Jan Didden

Book Review: Learning Audio Testing and Measurements

For those who need to refresh their knowledge or learn about audio test and measurements, Jan Didden reviews a great - and big! - book on the topic. Audio Tests & Measurements by Igor S. Popovitch is one of the many self-published works by this proficient writer based in Australia, also the author of several popular books on vacuum tube amplifiers. This particular book runs about 180 pages, but that is deceiving as the book’s format (A4 size) is about twice the size of most soft cover books.

Audio Myths: Why Narrow Bandwidth May Be Better also in the Time Domain.

June 22, 2023 by Jan Didden

Audio Myths: Why Narrow Bandwidth May Be Better also in the Time Domain.

This article expands the conversation around feedback theory for electronic circuits and audio amplifiers. Do we "really" need wideband open loop in audio amplifiers? The subject came up at the 154th Audio Engineering Society (AES) convention in Helsinki, Finland. Looking at the frequency domain, not necessarily, Jan Didden argued. In this article he looks at the question in the Time Domain. Narrow Bandwidth, High Open Loop Gain Amplifier versus a Wide Bandwidth, Low Open Loop Gain Amplifier in the Time Domain.

Audio Myths: Why Narrow Bandwidth May Be Better

June 15, 2023 by Jan Didden

Audio Myths: Why Narrow Bandwidth May Be Better

Although feedback theory for electronic circuits has been established for over a century, it is still a subject for discussion. This short essay is an attempt to shed some light on one of those recurring controversies. The subject came up at the 154th Audio Engineering Society (AES) convention in Helsinki, Finland. Audio amplifiers are basically integrators or, if you will, low-pass filters. That means that at some frequency, their open-loop gain starts to fall off. With that, the loop gain available for feedback also starts to fall off, leading to a diminishing of the curative effects of feedback: distortion starts to rise, gain accuracy starts to drop, output impedance starts to go up, etcetera.

The Internal Life of Vacuum Tubes

September 16, 2020 by Jan Didden

The Internal Life of Vacuum Tubes

A few years ago, Jan Didden designed a high-voltage delay unit and shared its details in a 2019 audioXpress article. Many people built it and like it, but others said that it would be totally unnecessary. As so often happens in audio, arguments pro and con raged without a clear resolution. So Didden thought this was something he needed to get his head around. He found several sources, which he thought were credible, and this article is the result of his investigations, fed by those sources. This article was originally published in audioXpress, August 2020.

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