Cyberbass Brings Bass Guitar To Modern Era

February 4, 2025 by Bryan Cockfield 19 Comments

For better or worse, the fundamental design of guitars has remained familiar since they electrified around a century ago. A few strings, a fretboard, and a body of some sort will get you most of the way there for an acoustic guitar, with the addition of electromagnetic pickups and wiring for electric variants. However, technology has advanced rapidly in the last 100 years outside the musical world, so if you want to see what possibilities lie ahead for modernizing guitars take a look at the Cyberbass created by [Matteo].

The guitar starts its life as many guitars do: with a block of wood. One of the design goals was to be able to use simple tools to build the guitar, so the shape of the instrument was honed with a Japanese hacksaw and the locations for the pickups and other electronics were carved out with chisels.

The neck of the guitar was outsourced since they take some pretty specialized tools to build, so simply bolting it to the body takes care of that part of the build, but [Matteo] had a few false starts setting the bridge in the exact location it needed to be.

Luckily he was able to repair the body and move the bridge. With the core of the guitar ready, it was on to paint and then to its custom electronics. [Matteo] built in not only a set of pickups and other common electric guitar parts but also integrated a synth pedal into the body as well as including a chromatic tuner.

With everything assembled and a few finishing touches added including a custom-engraved metal signature plate, the Cyberbass is ready to go on tour. [Matteo] learned a lot about guitar building in general, as well as a few things about electronics relating to musical instruments (including how expensive tuners work just as well as cheap ones).

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Homebrew Foil And Oil Caps Change Your Guitar’s Tone

February 4, 2025 by Dan Maloney 47 Comments

How any string instrument sounds depends on hundreds of factors; even the tiniest details matter. Seemingly inconsequential things like whether the tree that the wood came from grew on the north slope or south slope of a particular valley make a difference, at least to the trained ear. Add electronics into the mix, as with electric guitars, and that’s a whole other level of choices that directly influence the sound.

To experiment with that, [Mark Gutierrez] tried rolling some home-brew capacitors for his electric guitar. The cap in question is part of the guitar’s tone circuit, which along with a potentiometer forms a variable low-pass filter. A rich folklore has developed over the years around these circuits and the best way to implement them, and there are any number of commercially available capacitors with the appropriate mojo you can use, for a price.

[Mark]’s take on the tone cap is made with two narrow strips of regular aluminum foil separated by two wider strips of tissue paper, the kind that finds its way into shirt boxes at Christmas. Each of the foil strips gets wrapped around and crimped to a wire lead before the paper is sandwiched between. The whole thing is rolled up into a loose cylinder and soaked in mineral oil, which serves as a dielectric.

To hold the oily jelly roll together, [Mark] tried both and outer skin of heat-shrink tubing with the ends sealed by hot glue, and a 3D printed cylinder. He also experimented with a wax coating to keep the oily bits contained. The video below shows the build process as well as tests of the homebrew cap against a $28 commercial equivalent. There’s a clear difference in tone compared to switching the cap out of the circuit, as well as an audible difference in tone between the two caps. We’ll leave the discussion of which sounds better to those with more qualified ears; fools rush in, after all.

Whatever you think of the sound, it’s pretty cool that you can make working capacitors so easily. Just remember to mark the outer foil lead, lest you spoil everything.

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Get More Freedom With This Guitar Pedal

August 19, 2024 by Bryan Cockfield 13 Comments

When the electric guitar was first produced in the 1930s, there was some skepticism among musicians as to whether or not this instrument would have lasting impact or be a flash-in-the-pan novelty. Since this was more than a decade before the invention of the transistor, it would have been hard then to imagine the possibilities that a musician nowadays would have with modern technology to shape the sound of an instrument like this. People are still innovating in this space as well as new technology appears, like [Gary Rigg] who has added a few extra degrees of freedom to a guitar effects pedal.

A traditional expression pedal, like a wah-wah pedal, uses a single motion to change an aspect of the sound of the guitar, and is generally controlled with the musician’s foot. [Gary]’s pedal, on the other hand, can be manipulated in three different ways to control separate elements of the instrument’s sound. It can be pitched forward and back like a normal effects pedal, but also rolled side-to-side and twisted around its yaw axis. The pedal has a built-in IMU to measure the various position changes of the pedal, which is then translated by an RP2040 microcontroller to a MIDI signal which controls the three different aspects of the sound digitally.

While the yaw motion might be difficult for a guitarist to create with their foot while playing, the idea for this pedal is still excellent. Adding in a few more degrees of freedom gives the musician more immediate control over the sound of their instrument and opens up ways of playing that might not be possible or easy with multiple pedals, with the MIDI allowing for versatility that might not be available in many analog effects pedals. Not every pedal needs MIDI though; with the help of a Teensy this digital guitar pedal has all its effects built into a self-contained package.

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A black guitar with red rings on its body is held by a man in a black shirt. Text pointing to the red ring of guitar picks says, "This spins."

1000 Picks Make For A Weird Guitar

August 6, 2024 by Navarre Bartz 1 Comment

String instruments have a long history in civilization, helping humans make more complex and beautiful music. We wonder what our forebears would think of this guitar strummed with 1000 picks?

[Mattias Krantz] wondered what the best number of picks was to play guitar and took the experiment to its illogical extreme. Starting with zero picks and working up through various 3D printed multi-picks he tests all the feasible combinations of handheld picks.

After that, he switches gears to a fishing rod-actuated system of several picks in a ring. Not pleased with the initial acoustics of the picks in this system, he switched to printing his picks in a more flexible filament to better approximate the characteristics of the human thumb. Finally, he takes us to the undiscovered country of a spinning ring of 1000 picks strumming the underside of the strings and the… interesting acoustic result. As many pointed out in the comments, this blurs the line between a guitar and a hurdy gurdy.

If you want more melodic musical mischief, perhaps try this optical guitar pickup, a $30 guitar build, or get fancy with a 3D printed violin?

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Rock Out Without Getting Knocked Out

June 27, 2024 by Alexander Rowsell 20 Comments

It’s a constant battle for musicians — how to practice your instrument without bothering those around you? Many of us live in apartments or shared accommodation, and having to wait until the apartment is empty or only being able to practice at certain times of day can be restrictive, especially if you need to practice for an upcoming gig or if the creative juices start flowing and it’s 3 AM! [Gavin] was having this issue and started developing Porter, a guitar/bass practice device which works with all effects pedals and is portable and rechargeable. So you can grind away your epic heavy metal solo no matter the time of day!

While there have been similar solutions, many musicians weren’t satisfied with the sound and often couldn’t support inputs from distortion pedals. They usually chewed through batteries and were just not a great solution to the problem. [Gavin] has spent the last two years fine-tuning the design. It’s a fully analog design, with built-in rechargeable batteries to boot. So it not only sounds great, but it can last as long as your practice session does with a 15-hour runtime when fully charged!

Initially, the project began as a headphone amplifier but morphed into a design specifically for guitar and bass, with preamp and power amp stages and adjustable input impedance – 500kΩ for guitars and 1MΩ for bass. The latest revision also changed to a different power amp that further reduced THD and led to an even better sound. The schematics are up on the Hackaday.io project page, but [Gavin] is also hoping to do a crowdfunding campaign to get these devices out into the hands of guitarists everywhere!

Optical Guitar Pickup Works With Nylon Strings

March 4, 2024 by Lewin Day 67 Comments

Electric guitar pickups rely on steel strings interfering with a magnetic field, the changes in which are picked up with coils of wire. That doesn’t work with nylon strings, because they don’t tend to perturb magnetic fields nearly as much, beyond some infinitesimal level that some quantum physicist could explain. So what do you do? You follow [Simon]’s example, and build an optical pickup instead.

The concept is simple. You place an LED and a phototransistor in a U-shaped channel, and place it so that the string runs through it. You repeat this for each string. Thus, as a string vibrates, it interrupts the light travelling from the LED to the phototransistor. This generates a voltage that varies with the frequency of the string’s vibration. Funnily enough, this type of pickup will work just fine on both nylon and steel strings, if you were so inclined to try it.

[Simon] designed a nifty PCB with six LED-phototransistor pairs (using off-the-shelf interruptor sensors) for use with a nylon-stringed guitar. He reports that sound from the strings comes through clearly, but that there is some noise that is evident in the pickup’s output, too. Listening to the demo, it seems to capture the sound of the nylon strings well, it’s just a shame that the noise floor is so high.

If you prefer your guitar pickups to be the regular magnetic kind, you can always wind your own from scrap. Demo after the break.

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Building A Loop Station With An RP2040

January 11, 2024 by Lewin Day 9 Comments

Loop stations are neat things, able to replay one or more loops of audio over and over again while you perform over the top of them. Musicians like [Marc Rebillet], [Reinhardt Buhr], and [Dub FX] have made careers out of this style of performance. [Yaqi Gao], [Xiaoyu Liang] and [Alina Wang] decided to build a loop station of their own, using the popular RP2040 chip.

At its simplest, a loop station must take in audio, record it, and then play it back. Generally, it can do this with several tracks and mix them together, while also mixing in the incoming audio as well. The group achieved this by inputting a guitar signal to the chip via an amplifier and the onboard analog-to-digital converter. The audio can be recorded as desired, and then played back via an external digital-to-analog converter. Live audio from the guitar is also passed through to allow performing over the recorded sound. The group also used an external half-megabyte FRAM chip to allow storing additional audio sample data, which can be trucked out over serial and saved.

It’s not the cleanest loop station in the world, with a relatively low sample rate causing some artifacts. Regardless, it definitely works, and taught the group plenty about working with digital audio in the process. For that reason alone, we’d call it a success.

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