synth

127 Articles

Abacus Synthesizer Really Adds Up

June 15, 2022 by 4 Comments

The abacus has been around since antiquity, and takes similar forms over the hundreds of cultures that have embraced it. It may be one of the first devices to be considered as having a “user interface” in the modern context — at least for simple arithmetic calculations. But using an abacus as the UI for a music synthesizer seems like something entirely new.

Part art concept project and part musical instrument, the “Abacusynth” by [Elias Jarzombek] is a way to bring a more visual and tactile experience to controlling a synth, as opposed to the usual knobs and switches. The control portion of the synth consists of four horizontal rods spanning two plywood uprights. Each rod corresponds to a voice of the polyphonic synth, and holds a lozenge-shaped spinner mounted on a low-friction bearing. Each spinner can be moved left and right on its rod, which controls the presence of that voice; spinning the slotted knob controls the modulation of the channel via photosensors in the uprights. Each rod has a knob on one side that activates an encoder to control each voice’s waveform and its harmonics.

In use, the synthesizer is a nice blend of electronic music and kinetic sculpture. The knobs seem to spin forever, so Abacusynth combines a little of the fidget spinner experience with the exploration of new sounds from the built-in speaker. The synth also has a MIDI interface, so it works and plays well with other instruments. The video below shows the hardware version of Abacusynth in action; there’s also a web-based emulation to try before you build.

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Relax And Enjoy This Simple Drone Synthesizer

May 29, 2022 by 2 Comments

You’d think that a synthesizer that makes as much noise and sports as many knobs as this one would have more than a dozen transistors on board. Surely the circuit behind the panel is complex, and there must be at least a couple of 555 timers back there, right?

But no, the “Box of Beezz” that [lonesoulsurfer] came up with is remarkably simple. It takes inspiration from a [Look Mum No Computer] circuit called the “Circle Drone of Doom,” which used six switchable relaxation oscillators to make some pretty cool sounds. The Box of Beezz steps that up a bit, with four oscillators in three switchable banks in the final version. Each oscillator has but one transistor with a floating base connection and a simple RC network on the collector. The sawtooth outputs of these relaxation oscillators can be adjusted and summed together, resulting in some surprisingly complex sounds. Check out the video below for a bit of the synth’s repertoire — we’d swear that there are points where we can hear elements of the THX Deep Note in there.

We poked around a bit to understand these oscillators, and it looks like these qualify as avalanche relaxation oscillators. [lonesolesurfer]’s notes indicate that SS9018 transistors should be used, but in the photos they appear to all be 2N4401s. We’re not sure how long the transistors will last operating in the avalanche mode, but if they quit, maybe some neon tubes would work instead.

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Mini MIDI Synth Uses Minimum Number Of Parts

May 1, 2022 by 18 Comments

The 80s were the golden age of synthesizers in pop music. Hugely complicated setups that spared no expense were the norm, with synths capable of recreating anything from pianos and guitars to percussion, strings, and brass. These types of setups aren’t strictly necessary if you’re looking to make music, though, especially in the modern age of accessible microcontrollers. This synthesizer from [Folkert] with MIDI capabilities, for example, creates catchy tunes with only a handful of parts.

This tiny synth is built around an ESP32 and works by generating PWM signals normally meant for LEDs. In this case, the PWM signals are sent through a rudimentary amplifier and then on to an audio output device.  That could be a small speaker, an audio jack to another amplifier, or a capture device.

The synth’s eight channels use up most of the ESP32’s I/O and provide a sound that’s reminiscent of the eight-bit video game era. The total parts count for this build is shockingly small with only a handful of resistors, the ESP, an optocoupler, and a few jacks.

For those wishing to experiment with synthesizers, a build like this is attractive because it’s likely that all the parts needed are already sitting around in a drawer somewhere with possibly the exception of the 5 pin DIN jacks needed for MIDI capabilities. Either way, [Folkert] has made all of the schematics available on the project page along with some sample mp3 files. For those looking to use parts from old video game systems sitting in their parts drawer, though, take a look at this synthesizer built out of a Sega Genesis.

A computer program written in basic next to a modular synthesizer with many switches and lights

Modular Synth Pairs Perfectly With The Apple II

February 4, 2022 by 4 Comments

We have a soft spot for synthesizers – seriously, who doesn’t? So when [Joshua Coleman] combined his retro-looking DIY modular synth with the equally retro Apple II computer, we just had to share it with you.

The two machines are paired using a vintage digital-to-analog logic controller pack. This DAC was originally used to control model trains using your Apple II – something that we now desperately need to see in action. The pack can output voltages between 0 and 2.55 V at 8-bit resolution (or 256 steps), which is plenty for a retro synth.

With the card installed in Slot 7 of the Apple II and the DAC wired through to the synth’s CV/gate, it’s then a trivial matter of writing POKE statements in Applesoft BASIC to control the synth. The video after the break demonstrates playing a simple melody, as well as how one might use the Apple II keyboard to ‘play’ the synth in real time.

If you’re interested in building your own, the video below has all the information needed, as well as helpful advice on where to find a DAC for your preferred model of vintage computer. If all that doesn’t tickle your musical fancy, make sure to check out our coverage on the Game Boy MIDI synth, or perhaps this peculiar synth and visualizer combo.

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Artist operating artistic visualizer with MIDI keyboard

Synth And Visualizer Combo Has Retrocomputing Vibe

January 11, 2022 by 7 Comments

[Love Hultén]’s latest piece of interactive art is the SYNTH#BOI, a super-clean build with something of the semi-cyberdeck, semi-vintage computing vibe to it. The device is a combination synthesizer and visualizer, with a 15-inch display, MIDI keyboard, and based on an Intel NUC i5 small form factor PC.

There are not many details about the internal workings of the device, but the high quality of the build is very evident. Photos show a fantastic-looking enclosure with clean lines and sharp finish; it’s a reminder that careful measuring and attention to detail can be the difference between something that looks like a hack job, and something that looks like a finished product.

Watch the SYNTH#BOI in action in the video, embedded below. And if the name [Love Hultén] seems familiar, it’s probably because we featured his VOC-25 “Pink Denture Synth”, a concept instrument with a decidedly memorable design of its own.

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Vacuum tube Atari Punk Console

The Atari Punk Console, Now With More Vacuum Tubes

January 11, 2022 by 7 Comments

Most of us have beheld the sonic glory of an Atari Punk Console, that lo-fi synth whose classic incarnation is a pair of 555 timers set up to warble and bleep in interesting ways. Very few of us, however, have likely seen an APC built from 555s that are made from vacuum tubes.

It’s little surprise to regular readers that this one comes to us by way of [David] at Usagi Electric, who hasn’t met a circuit that couldn’t be improved by realizing it in vacuum tubes. His “hollow-state” Atari Punk Console began with the 18-tube version of the 555 that he built just for fun a while back, which proved popular enough that he’s working on a kit version, the prototype of which served as the second timer for the synth. With 32 tubes aglow amid a rats-nest of jumpers, the console managed to make the requisites sounds, but lacked a certain elegance. [David] then vastly simplified the design, reducing the BOM to just four dual-triode tubes. Housed on a CNC milled PCB in a custom wood box, the synth does a respectable job and looks good doing it. The video below shows both versions in action, as well as detailing their construction.

As cool as a vacuum tube synth may be, we realize that not everyone goes for the hot glass approach. No worries — plenty of silicon Atari Punk Consoles to choose from here. There’s one built into a joystick, a circuit sculpture version complete with mini-CRT, or even eight APCs teamed up with MIDI control.

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Ken Shirriff Breaks Open The Yamaha DX7

November 25, 2021 by 23 Comments

For better or worse, this synthesizer was king in the 1980s music scene. Sure, there had been synthesizers before, but none acheived the sudden popularity of Yamaha’s DX7. “Take on Me?” “Highway to the Dangerzone”?  That harmonica solo in “What’s Love Got to Do With It?”  All DX7. This synth was everywhere in pop music at the time, and now we can all get some insight from taking a look at this de-capped chip from [Ken Shirriff].

To be clear, by “look” that’s exactly what we mean in this case, as [Ken] is reverse-engineering the YM21280 — the waveform generator of the DX7 — from photos. He took around 100 photos of the de-capped chip with a microscope, composited them, and then analyzed them painstakingly. The detail in his report is remarkable as he is able to show individual logic gates thanks to his powerful microscope. From there he can show exactly how the chip works down to each individual adder and array of memory.

[Ken]’s hope is that this work improves the understanding of the Yamaha DX7 chips enough to build more accurate emulators. Yamaha stopped producing the synthesizer in 1989 but its ubiquity makes it a popular, if niche, platform for music even today. Of course you don’t need a synthesizer to make excellent music. The next pop culture trend, grunge, essentially was a rebellion to the 80s explosion of synths and neon colors and we’ve seen some unique ways of exploring this era of music as well.

Thanks to [Folkert] for the tip!