Sometime in the back end of the 1980s, I found my fingers strumming on the worst excuse for a guitar I had ever come across. I had picked up the Casio DG-1 from the wall of a music shop. This thing looked extraordinary. At the time, there were a few futuristic-looking guitar synths, such as the Roland G-707 with its over-reaching arch of weirdness, and the bizarre Stepp SynthAxe that seemed to bend space and time in the pursuit of fretboard-based synth action. But they were fever-dream machines that were out of reach of the strapped-for-cash teenager. Maybe the famously affordable, and famously plastic Casio alternative could turn me into the synth performance spaceman I longed to be.

My first impressions were less than stellar. The strings were saggy lengths of black nylon that lacked any of the tension you'd expect strings to have. The rubberized fretboard felt odd under my fingers and needed a bit of pressure through the string to secure the note, although the string seemed largely irrelevant. The strings would clack as you plucked, while notes from a handful of built-in sounds limped out of the built-in speaker. The automatic rhythms were very jolly, but drew plenty of smirks from other music shop browsers as I struggled to play along and make it sound intentional.

I put it back on the wall and left. However, there's more to these plastic instruments than I ever allowed them to reveal. And given a little bit more time and perhaps some musical maturity, they could be quite fascinating. Let's dig a little deeper into the Casio DG series.

Original Release Date?

But first, we need to do some detective work. The internet seems to believe that the Casio DG-1 made its debut in 1981. There are multiple YouTube thrift-store-find videos that state 1981 as the year of release, as do many eBay auctions and articles on the internet. If you poke about in various AI systems they generally agree on 1981, while giving a nod to 1984 and 1982 depending on how you phrase the question. All of these dates seem terribly unlikely. 1981 was the year of the Moog Rogue One, Roland Jupiter-8, Korg Polysix, and Oberheim Ob-Xa. Had the DG-1 been released at this time, it would have been covered in wood grain veneer and big candy-shaped buttons like the Casiotone keyboard. It would be years before we’d see Casio come up with the sort of controls we have on the digital guitar. The DG-1 manual mentions that the rhythms are PCM-based, a sampling technology that had only just begun making an impact in drum machines such as the LinnDrum and Oberheim DMX.

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The DG-10, released in 1987, was largely identical to the DG-1. The similarities would suggest that they were released close together. Casio doesn’t even list it as a product in their historical timeline, instead choosing to highlight the DG-10. Through my research, I could find no advert, review, or brochure that could confirm the date of the DG-1, and was left with the weight of internet opinion saying it was 1981, and everything I know about synths telling me it wasn’t. Eventually, I posted this query onto a couple of Facebook groups, where the consensus was that 1981 wasn’t right. Then we had a breakthrough. A YouTuber calling themselves Casio Chaos Theory sent me a link to a video he had made 6 months earlier about a pair of DG-20s he bought off eBay. During the video, he was able to show a couple of pictures from a German Casio brochure that confirmed that the DG-1 was actually part of a series of digital guitars that Casio released at the same time.

So, the correct historical context is that Casio released the whole DG Series in 1987. It started with the DG-10, followed by the upgraded DG-20 and then the simpler, entry-level DG-1 and grey-coloured variant, the DG-7. This explains why Casio only refers to the DG-10 in their product archive—because the rest were simply variations on that first guitar. Somewhere out on the internet, the release date of the DG-1 has been subverted, but hopefully this article will help redress that inaccuracy.

Inspiration

There does appear to be a strong desire in the late 1970s and early 1980s to combine the synthesizer's sonic versatility with the guitar's performative advantages. Hanging a synth around your neck just didn't seem to do it (although many had tried), and plenty of very capable musicians didn't play keyboards. The most common solutions came in the form of analog multi-effects like the Maestro USS-1 and the EMS Synthi Hi-Fli, but these were more about transforming a guitar sound rather than letting a guitar play a synthesizer. In 1977, Roland changed the game by introducing the GR-500. It took the vibrating strings of a guitar and captured the frequency through an innovative hexaphonic pickup, to drive a synthesizer sound module. This evolved into the 1979 GR-300 floor unit and guitar system that has pretty much been the benchmark ever since. However, this has absolutely nothing to do with how the DG Series makes its sound.

A more direct inspiration probably comes from the 1984 Synth Axe controller and the 1986 Stepp DG1 guitar synth. Both these guitars approached the concept differently to the Roland. Pitch detection required a certain amount of time to establish the frequency of a string vibration. This could cause a bit of lag, and poor tracking could result in wrong notes and other frustrations. The Synth Axe and Stepp DG1 bypassed this problem by taking the Guitar Organ/GuitOrgan route. Released in 1966 by Vox and Murrell Electronics respectively, these were real guitars that had organ elements built into them. The frets were split into six contact switches, giving each string its own voice. Notes sounded whenever the string was pushed against the fret. Controls for the organ sound were built into the body of the guitar, and you were able to mix the regular electric guitar sound along with it.

The point here is that the guitar wasn’t trying to detect the frequency of the string in order to generate the note of the organ; it was done through the switches on the fretboard. The Synth Axe and Stepp used a similar idea with sensors under the fretboard, and then Casio followed. The Synth Axe was massively expensive and fabulously expressive, outstripping the performance of any Roland guitar synth system, but had no sound of its own. The Stepp DG1 had an entire synthesizer built in and was a more complete instrument for a lot less than the Synth Axe, but still more than a regular guitar or synthesizer. Casio did it a year later for a couple of hundred bucks.

How it Worked

Casio’s range of Casiotone home keyboards followed the idea of giving the player a range of useful preset instrument sounds along with some pre-made drum patterns to accompany them. The melodic sounds were generated using a sort of digital-analog hybrid sound source called vowel-consonant synthesis that pushed a pair of digitally sampled waveforms through a switchable lowpass filter. Typically, one waveform was used for the attack and the other for the sustain portion of the sound. It was simple but effective and was used by Casio on a range of instruments from 1981 through to 1987. It was this sort of sound generation that was used in the DG series.

Plastic nylon strings were attached to sensors under the bridge of the guitar that would detect the vibration and trigger the sounds. The rubberized fretboard had capacitive switches behind every fret that would set the pitch of the string as you pressed it with your finger. The strings were independent, giving you 6-note polyphony, and you could pluck or strum them to bring forth the music.

There were two types of sound or “tone”. Some decayed naturally, like “Acoustic Guitar”, whereas others, like the “Organ”, would sustain until you released the pressure on the fretboard or used the Mute switch to kill the sound. The guitar ran on a handful of AA batteries, and through the onboard speaker it sounded a lot like a slightly panicked home keyboard. You could choose from a few sounds, such as acoustic and electric guitar, mandolin, organ, harp, and glockenspiel.

It was an odd and unique way of playing, but it had the same massive advantage over the Roland guitar synth technologies as the Synth Axe and Stepp DG1 - there was no pitch tracking. This made it very fast and accurate, letting you play licks, hammer-ons, pull-offs, and slides at virtuosic speeds. However, as it had nothing to do with the strings, there was no ability to pitch bend or add vibrato by wobbling your fingers. Some of the sounds had a delayed modulation built in that gave the impression of vibrato.

The drum sounds were based on PCM samples and sounded pretty current. The rhythm patterns were classics such as Rock, Reggae, Bossa Nova, Tango, Country, and Waltz, amongst others. It had a Synchro Start and Fill button so it would kick in when you started playing and throw in a fill on a touch.

The Series

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All the guitars shared the same sound engine, rhythm section, and associated technology. They all had the same flaccid strings, rubberized fretboard, and similar futuristic looks. But there were some very key differences.

DG-10

The DG-10 was put forward as the standard bearer of the series. It had 12 tones and a total of 12 different rhythms with auto-fills. Most of the controls were all along the top of the guitar body, making them easy to access, and used membrane-style buttons that were very popular at the time. There's a built-in reverb/sustain effect, and you can transpose up to 11 semitones, so you'd never need a capo. A "Solo" mode helped you nail those lead solos without accidentally triggering other notes.

On the front of the guitar were the volume knobs for the main sound and a separate one for the rhythm section. You’d also find a mute switch, start/stop and synchro/fill buttons. For connections, it just had a minijack output and a power connector.

DG-20

While appearing to be physically identical to the DG-10, the DG-20 had one humble but earth-shattering addition: a MIDI output port. Forget all the onboard sounds and rhythms; you could play any MIDI-equipped synth or sound module polyphonically over six strings. But it could do more than that. You could set each string to a different MIDI channel and send each string to a different instrument that plays a different sound. Suddenly, the DG-20 was able to produce layers of sound from multiple sources with the flourish of your fingers. At around $300, it was by far the most affordable way to control synthesizers with a fretboard-based instrument.

In addition to the MIDI, you got an extra 8 tones, taking the total up to 20. On the front of the guitar, Casio added four drum pads for taking manual control of the snare, low and high toms, and the cymbal. The DG-20 also upgraded the audio connections to 1/4" jacks; you had a separate line out and headphone output alongside a footswitch input for starting and stopping the rhythms.

While the DG-10 could give you a fair bit of fun, provided you found the sounds to your liking, it's hard to see it as anything other than a toy-like curiosity. Whereas with the MIDI and more professional connections, the DG-20 was able to shake off some of the novelty and make itself useful in both a music production and performance environment.

Casio DG-1 + DG-7

Now we know where the DG-1 came chronologically, it makes sense that this would have been a cutdown, entry-level version of the DG-10.

Although—other than the shape, it wasn’t cut down very far. It still has the same number of tones and rhythms as the DG-10. All the controls are now on the front of the guitar on a more regular style of button. The only significant loss is the Sustain/Reverb effect and transpose options.

The DG-7, which you might come across when looking for the DG-1, appears to be just a colour variant that, it’s been suggested, was only available in Japan.

Guitar Shift

By the end of the 1980s, there were a number of digital guitars from various brands offering extraordinary looks and fabulous synthetic sounds, but for one reason or another, they seemed to just vanish. I imagine the convenience of having MIDI built into a real guitar won out over having something specific, with terrible strings and a different way of playing.

Casio left the DG series behind and went on to produce a range of hybrids that built MIDI or synths into the bodies of real guitars. The MG500 MIDI guitar followed the futuristic design of the DG series but was built around a real guitar. The MG510 brought things back to normality by being based on the shape of a Fender Strat. Both these models shift to using pitch detection in order to produce the MIDI notes, just like other guitar synths. And just like other guitar synths, the player had to cope with translation delays and tracking issues from which the DG series never suffered.

However, Casio was doing it more integrally and affordably than any other brand at the time. A year later, in 1988, Casio built a synth back into the MG510 and turned it into the PG380 Guitar Synth. The sounds were taken from their Interactive Phase Distortion technology that was also found in the VZ1 synthesizer.

Casio's shift into real guitars is largely forgotten as Roland cornered the market with their GK-1 guitar synth pickup that could turn any guitar into a MIDI guitar synth. However, the appeal of the DG-20 still lives on and has achieved legendary status in some weird backwaters of the internet for its innovation and futurism.

Still Relevant?

Today, digital guitars are not uncommon; however, the vast majority rely on pitch-to-MIDI conversion and hexaphonic pickups to capture the pitch information from the frequency of the strings. Latency and tracking glitches have much improved from the 1980s, but there are still issues and a certain amount of compromise at play.

MIDI guitars that follow the DG-20 method of producing notes are much rarer. One such possibility is the Aeroband Guitar. It looks like a regular guitar, but the strings stop at the fretboard, giving you a place to pick and strum while not interfering with the placement of your fingers. It’s probably the closest thing to the Casio out there, and for a similar sort of price.

There seems to be a healthy second-hand market for these Casio digital guitars, so I imagine there’s space for something playful and futuristic if Casio ever wants to return.

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