Analog Devices A2B Adopted by Roland Guitar Synthesizer Group

Analog Devices continues to expand its A2B digital audio connectivity technology with new transceiver devices and updating the specification that enables powerful multichannel audio applications. Originally developed by Analog Devices for audio data transmission in automotive applications, A2B has been adopted also as a new data transmission technology for professional audio by multiple brands. And it has now been commercially adopted even in synthesizers.

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

Read audioXpress July 2022 to learn the latest about Audio Amplification technology, an interesting perspective on audio bandwidth measurements, and read the AXPONA 2022 report. On DIY audio, this issue offers a solid-state, modular preamplifier project by Bruce Heran, the Egg Speaker Amp and System by Reinhardt Metz, and how to achieve a triode sound by Richard Honeycutt. And Ethan Winer describes the input stages for his Guitar-Controlled Synthesizer project.

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.