Korg returns to the production of analog synthesizers with the Monotron. In fact, since the end of the 80s, Korg has dedicated itself exclusively to the production of digital machines, thus leaving the analog market to other companies, obviously leaving out virtual analog and software. This small analog synth, controllable via ribbon, therefore represents the return to the analog tradition of the Japanese multinational.
Packaging and features:
The package, also very small, contains only the Monotron, wrapped in a protective bag, and the instruction booklet. The batteries - two mini-stylus (AAA) - are already pre-installed in the unit and should allow a runtime of approximately 8 hours.
Fig.1
The synth features a fairly simple layout which includes a VCO, VCF, LFO and a small internal speaker. The feature that immediately catches the eye is certainly the filter, borrowed from the glorious MS-20. The potentiometers, although small, respond very well as does the ribbon controller.
Small glossary of terms used VCO = Voltage Controlled Oscillator, or Voltage Controlled Oscillator, generates the waveform (the sound) that we hear from the Monotron.
VCF = Voltage Controlled Filter, or Voltage Controlled Filter, filters certain frequencies on a threshold called the “cutoff”.
Cutoffs = Cut-off point, which, according to the type of filter used, eliminates the frequencies above or below the chosen threshold.
Peak = Known as Resonance or Emphasis, it is the parameter that emphasizes the frequencies near the cut point creating a very particular effect.
LFO = Low Frequency Oscillator, or Low Frequency Oscillator, generates a waveform (low frequency) that acts as a modulator.
Pitch = Height of the sound.
fig.2
The controls The controls available on the Monotron are:
Pitch of the VCO
Rate of the LFO
Intensity of LFO modulation
Filter cutoff
Peak or the resonance of the filter
Volume
Assign modulation to pitch or filter
Ribbon controller to control the pitch
Fig.4
There is an AUX input, which allows you to process an external audio source with the internal filter of the Monotron, and the headphone output, which can obviously also be used as a generic output. Both inputs are stereo minijacks (although the output is actually mono). The Monotron, as already mentioned, is equipped with a small speaker which does not do justice to its sound.
The synth
The Monotron, although it looks like a toy, is in all respects a mister analog synth. It doesn't have much to envy to the old single oscillator analog synths. Although I use a VCO the sound is very stable. The manual suggests waiting 30 seconds from switching on before the oscillator stabilizes, but in reality it takes much less and in any case it is a hardly noticeable effect. The potentiometer of the pitch in practice, it has the same function as the ribbon, it simply “tunes” the oscillator.
The ribbon controller, cute as it is, is perhaps the only flaw. Using your fingers it is very difficult to intone a precise note: this unfortunately downgrades this splendid synth to a very simple noise maker in the eyes (and ears) of most. You can get better control of the intonation by using a stylus (not included) like the one for PDAs, mobile phones or other, but another problem arises: the ribbon only responds if the stylus is in the center, so it doesn't take much to make it sound. This obviously cannot happen using your fingers as you cover the entire surface of the ribbon with your fingertip.
The LFO is assignable to both pitch and cutoff and has the two classic parameters rates (i.e. the frequency of the LFO) e int. (which stands for intensity intensity), that is, the amount of modulation to assign. The potentiometer of the rates it is actually also a handy led that visually shows the LFO frequency.
It seems almost unbelievable for such a small object, but the real highlight is the filter. Just connect the Monotron to monitors (thus bypassing the internal speaker) to realize the power of this little machine. There are two classic controls, cut off e peak, Korg nomenclature that identifies the resonance filter.
Next to the volume, which is a "washer" potentiometer like the old Walkman or the radios, there are the two minijacks (AUX and headphones) for input and output. Unfortunately minijacks are uncomfortable because they often force us to use flying or unstable adapters: for this reason it is better to have cables made specifically for our needs.
Modification
The Monotron, due to its size and the simplicity of the scheme (in fact all the important points such as filter, gate, pitch, etc. are marked on the circuit), easily lends itself to more or less invasive modifications. Clearly, for a physical factor, there is no possibility of powering the Monotron through an external power supply. However, it is quite simple to make a power supply input from the connectors in the battery compartment. Also online there are a number of videos and articles on some more direct changes, such as a change to add the midi or how to add another VCO (the site is in Japanese but the diagrams are present).
Fig.3
Conclusions
Chatting with a friend, who is also a fan of synths, we wondered: considering the now small size of these devices, how much would it cost a company like Korg to produce some more serious but economically convenient analogue machine? If a MIDI input had been present but also simply the possibility of driving it via USB (as you can see in figure 3, there is all the space for a miniUSB port and relative IC to control it) many people would have probably paid double it.
Fig.5
However, considering the low cost and the tonal qualities, the Monotron is certainly a very attractive analog synth. However, it must be taken into consideration that the main use of the Monotron will certainly be "leisure" as it is unlikely with the ribbon that it will be possible to use it seriously in productions that do not require various noises and effects. Clearly the Monotron lends itself well to experimental music and can be very useful for DJs to process the audio in the synth's internal filter.
Personally, I keep it fixed on my desk when I surf the internet or when I watch a movie, and very often I turn it on between various breaks or dead moments, even if just to play with the filter for a while.
Sheet
Pro: Low cost and very interesting sound. Portability. Possibility to process external audio sources with the internal filter.
Against: Not very versatile and difficult to control for the intonation of notes via ribbon.
Extra: Being an analog synth it is important to also take into account environmental factors such as temperature and humidity that can affect some parameters such as the LFO rate or the pitch of the VCO.
Korg is back to the production of analog synthesizers with Monotron. Since the late '80s, in fact, Korg is dedicated to the production of digital hardware, leaving the market of analog synthesizers to other companies, except for virtual analogs and softwares. This small analog synth, controllable via the ribbon, represents a return to traditional analog synthesis for the Japanese multinational.
Content and features
The package, very small, contains only the Monotron, wrapped in a protective bag, and instruction booklet. The batteries – two mini-stylus (AAA) – are already pre-installed in the unit and should enable a life of about 8 hours.
Fig.1
The synth has a fairly simple scheme that includes a VCO, a VCF, an LFO and a small internal speaker. The feature that catches one's eye is definitely the filter, borrowed from the glorious MS-20. The knobs, although small, respond very well as the ribbon controller.
Glossary of terms used VCO = Voltage Controlled Oscillator, generates the waveform (sound) we hear from the Monotron.
VCF = Voltage Controlled Filter, filter frequency on a certain threshold called the cutoff.
Cutoffs = according to the type of filter used eliminates precisely the frequency above or below the chosen threshold.
Peak = Known as resonance or emphasis, is the parameter that emphasizes the frequencies near the cutoff, creating a very special effect.
LFO = Low Frequency Oscillator, generates a waveform (low frequency) that acts as a modulator.
fig.2
Controls The controls available on Monotron are:
VCO Pitch
LFO Rate
LFO Intensity
Filter Cutoff
Filter Peak (resonance)
Volume
Modulation for pitch or filter
Ribbon controller for pitch
Fig.4
There is an AUX input, which allows you to process an external audio source with the internal filter Monotron, and headphone output, of course, it can also be used as a generic output. Both inputs are stereo mini-jack (although the output is really mono). The Monotron, as mentioned above, has a small speaker that does not do justice to its sound.
The synth
Monotron, although it seems a toy, is a very good analog synth. It has little to envy to the old single-oscillator analog synths. Although it uses a VCO the sound is very stable. The manual suggests to wait 30 seconds from power on until the oscillator stabilizes, but in reality you only need a few seconds and anyway it is a hardly noticeable effect. The pitch potentiometer, in practice, has the same function as the ribbon, just “tune” the oscillator.
The ribbon controller, although cute, is perhaps the only flaw. Using your fingers is very difficult to keep tuned notes: this unfortunately downgrading this wonderful synth as a simple noise maker in the eyes (and ears) of most. You can get a better control of intonation using a stylus (not included) such as PDA, mobile phones or anything, but another problem arises: the ribbon is only liable if the stylus is at the center. This of course can not happen using your fingers as you cover the entire surface of the ribbon with the fingertip.
The LFO is assignable to that cutoff and the pitch and the two classical parameters rates (the frequency of the LFO) and int. (which stands for intensity), or the amount of modulation to be used. The potentiometer rates is in fact a very useful LEDs that visually shows the frequency of the LFO.
It seems almost incredible for such a small object, but the real strength is its filter. Simply connect your monitor to Monotron (thus bypassing the internal speaker) to realize the power of this small hardware. There are two classic controls, cut off and peak, Korg nomenclature that identifies the resonance of the filter.
Next to the volume, which is a potentiometer “washer” or like the old walkman radios, there are two mini-jacks (headphones and AUX) for input and output. Unfortunately minijacks are often uncomfortable because they force us to use loose or unstable adapters: it is therefore better to equip themselves with cables made specifically for our needs.
Mods
The Monotron, for its size and simplicity of the scheme (on the circuit are marked all the important points as a filter, gate, pitch, etc. …), lends itself easily to more or less invasive mods (circuit bending). Clearly, for a physical factor, there is the possibility of feeding the Monotron external power supply. However, it is fairly straightforward to derive a power supply input from the connectors in the battery compartment. Also there are a series of videos and articles on some more immediate changes, such as an amendment to add the midi or how to add another VCO (site is in Japanese but there are diagrams).
Fig.3
Conclusion
Chatting with a friend, a synth-fan like me, we asked: considering the miniscule size of these devices, how much would it cost to a company like Korg building a complete but affordable analog synth,? If it was built-in a MIDI input or just a USB to MIDI (as shown in Figure 3, there is all the space for a miniUSB port on the IC and to control it), most people probably would have paid twice as much.
Fig.5
However, considering the low cost and quality of timbre, the Monotron is certainly a very attractive analog synth. But we must bear in mind that the main use of Monotron will certainly be “fun” as with the ribbon it's really hard to use it “seriously” in productions that require different sounds and effects. Monotron clearly lends itself well to experimental music and DJs and can be very useful to process the audio with the internal filter.
Personally I keep it on my desk when I browse the internet or when I watch a movie, and very often I turn it on just to play around with the filter.
Date
Pro: Cheap but sound very interesting. Portability. Can process external audio sources with the internal filter.
Cons: Not very versatile and very difficult to control the pitch with the ribbon.
Extra: As an analog synth it is important to take into consideration environmental factors such as temperature and humidity that may affect some parameters such as LFO rate or the pitch of the VCO.
fig.2
