Audio Electronics: Is Digital Jitter Really a Problem?

Since the dawn of the digital era decades ago, the timing error known as "jitter" in A/D/A converters has been accused of harming audio fidelity. Some people claim that jitter adds audible distortion and noise, affects bass fullness, and even harms stereo imaging width and depth. This article explains what jitter is, what causes it, and even lets you hear jitter in controlled amounts so you can decide for yourself how damaging it really is. Originally published in audioXpress, January 2024.

This original circuit effectively removes the low-frequency impulses caused by air blasts from a person speaking or singing into a microphone, as well as "plosives." This analog circuit removes these irritating sounds in real time, directly at the source by applying a 24-stage all-pass filter to delay only the lower frequencies of the main audio stream. This original circuit for non-commercial use is available for licensing for commercial manufacture. This article was originally published in audioXpress, October 2023.

The first article from audio expert Ethan Winer about Modern PCB Design Practices, gave a general overview of board design using surface-mounted devices (SMDs). The article examines current practices and methods for designing four-layer printed circuit boards using surface mounted components (SMDs), and this second part explains specific strategies and related issues to deal with the design and production of great quality PCBs. This article was originally published in audioXpress, March 2023.

In this two-part series, Ethan Winer examines current practices and methods for designing four-layer printed circuit boards using surface-mounted components (SMDs). A great article for our DIY readers and many developers who often are faced with the need to build and test their projects on a properly designed, prototype printed circuit board. Part 1 presents an overview of the process, while Part 2 he will explain specific strategies. Many related issues will be described along the way.

Ethan Winer offers his fifth Guitar-Controlled Synthesizer article where he describes how to make two key modules needed by every analog synthesizer: the Voltage Controlled Amplifier (VCA) and Voltage Controlled Filter (VFC). This article explains two different VCA circuits, with a simpler one that works fine for one-off projects where precise unit-to-unit repeatability isn’t needed, and a second circuit similar to the VCA in the original Moog synthesizers. This article was originally published in audioXpress, August 2022.

The three previous articles described circuits that Ethan Winer developed for his current project that uses an electric guitar instead of a keyboard to control an analog synthesizer. This article continues with two pieces needed to process input from an electric guitar: the input section’s preamplifier and noise gate, and the pick detector. The preamp amplifies the weak signal from an electric guitar’s pickup and brings it up to line level for further processing. The noise gate detects when a note is currently playing and when it stops. Of course, the pick detector signals each time a new note is picked.

This third article continues to follow Ethan Winer's fascinating journey of building modules for a Guitar-Controlled Synthesizer. The two previous articles described the core circuits he developed for this project that uses an electric guitar instead of a keyboard to control an analog synthesizer. This article continues with two components that are essential for all analog synthesizers: The Low Frequency Oscillator (LFO) and the Attack Decay Sustain Release (ADSR) envelope generator. Both of these circuits generate voltages that control other modules in the synthesizer. This article was originally published in audioXpress, June 2022

This is the second article in a fascinating DIY journey of a guitar-controlled, all-analog synthesizer project that will include multiple stages and modules. Following a Sample & Hold circuit designed to retrieve previous voltages that no longer exist, this article details voltage control and how the playing is converted to voltages and back to frequency.

This article initiates a fascinating DIY journey through the world of synthesizers. More specifically, a guitar-controlled all-analog synthesizer project that includes a "time machine" sample & hold section, input signal detectors, noise gate, oscillators, envelope generators, filters, signal converters, and more. This first module is a sample and hold circuit designed to translate the guitar notes to equivalent oscillator frequencies.

"Before you start measuring and playing around with your new speakers, maybe you should know your room." The statement, inspired Ethan Winer to write this article from a very practical perspective, helping us to understand the acoustics of our own listening rooms, and how measurements will help us. The examples contained in the article use the popular Room EQ Wizard (REW) software. This article was originally published in audioXpress, August 2021.