Roland Juno-60

src: medias.audiofanzine.com

The Roland Juno-60 is a popular 61-key polyphonic synthesizer introduced by Roland Corporation in September 1982 as a successor to the similar Roland Juno-6, which had been on the market since February that year. Like its predecessor, the Juno-60 is essentially an analog synthesizer with digitally controlled oscillators.

Roland was losing market share with the Juno-6 in competition against the Korg Polysix. Related in features and price-class, the Polysix featured programmable patch memory, which the Juno-6 lacked. Programmability and external control (via Roland's proprietary Digital Communications Bus (DCB)) were added to the Juno-6, which was then re-introduced as the Juno-60 (which sonically and architecturally did not change notably from its predecessor). Production of the Juno-6 ceased in August 1983.

The Juno-60 was widely used by many artists, and is considered to be one of the most important synthesizers in popular music. In February 1984 the Juno-60 was replaced by the Juno-106, a similar instrument with further incremental changes. The Juno-60's DCB interface was replaced by a MIDI interface.

Video Roland Juno-60

Features and synthesis architecture

Tone generation

The Juno-60 synthesizer is a six-voice polyphonic synthesizer. The single digitally controlled oscillator (or DCO for short) per voice gave the Juno-60 a high degree of stability in maintaining tune; most analogue voltage-controlled oscillators (VCOs) of the time would tend to drift in pitch and require re-tuning of the oscillator. The DCO provides sawtooth and square/pulse waveforms as a sound source, in addition to white noise and a square-wave suboscillator pitched one octave beneath the key played. Both of these additional sources can be mixed in with dedicated sliders.

The filters and envelope on the Juno-60 rely on control voltages sent by depressing the keys on the keyboard and were thus analogue. The Juno-60 features a rather distinctive-sounding 24 dB/octave lowpass filter with resonance. Unlike other VCF's of the day, the Juno-60's is capable of self-oscillation and thus could be used to some degree as a tone generator in and of itself. The filter section also features controls for envelope amount and polarity, LFO modulation, and keyboard tracking. In addition, a three-position non-resonant highpass filter is provided to thin out lower frequencies.

Modulation

The Juno-60 provides a single triangle-wave variable-rate LFO for modulation options. This is routed into the DCO to create pitch vibrato and pulse-width modulation, plus into the lowpass filter to generate a tremolo effect. All three choices can be used simultaneously, each with their own individual depth settings. The LFO can then either be triggered manually by the left hand using a large button above the pitch bend lever or set to engage automatically whenever a key was pressed. The LFO also features a slider to adjust a delay time for when it will be triggered automatically.

The signal is then sent through a voltage-controlled amplifier (or VCA) and a simple four-stage ADSR filter envelope. One unique feature of the envelope is its ability to also control the width of the pulse waveform.

Other features

The Juno-60, like the other Juno synthesizers, carries an on-board stereo chorus effect which, while noticeably noisy, adds a rather distinctive character to the sound of the instrument.

In addition, the Juno-60, like the Juno-6 but not the Juno-106, features an on-board up/down/up-down arpeggiator capable of spanning three octaves. The arpeggio speed can be controlled by either using a slider or an external trigger source. It is possible to improvise a trigger for the arpeggio by sending a short duration loud audio signal (for example a Roland TR-808 Rimshot sound) into this input.

The Juno-60 also contains 56 memory slots to retain and instantly recall patch settings. The Juno-60's memory can be dumped to (or loaded from) a magnetic cassette tape by plugging a tape recorder into the appropriate jack in the instrument's rear. Patch information is transmitted as an audio signal similar in quality to that produced by a computer modem.

The Juno-60 is controllable with sequencers using proprietary DCB protocol, similar to MIDI. Roland produced several DCB-enabled sequencers, or, alternatively, MIDI-to-DCB converters can be used to drive DCB-enabled synths. There are also at least two commercial third-party retrofits available to add MIDI on board the Juno 60. In the Juno-106, DCB support was dropped in favor of MIDI.

Finally, there is the test mode (only explained in the service manual):

To access the test mode, power up the Juno with the KEY-TRANSPOSE button pressed. You have three different key-assign modes while in test mode. You can select a key-assign mode with the arpeggio mode-switch (the switch has to be in the preferred position before powering up the Juno in test mode). Arpeggio mode-switch:

UP - All 6 voices are assigned to the last key pressed. This puts the Juno in unison mode (also transforming it into a monosynth).

UP/DOWN - The first key pressed might use voice 1, the next key pressed will use the next voice in the number order, and so on. If you keep 4 keys pressed and then release 3 of them, the next key will be assigned to voice 5. The available voices are always assigned in number order to the next key pressed, but the first key pressed does not necessarily assign voice 1.

DOWN - The first key pressed will use voice 1, the next key will use voice 2 and so on. However, if you keep 4 keys pressed and then release 3 of them in this mode, the next key will be assigned to voice 1 (except when it's unavailable). The available voice with the smallest number will always be assigned to the next key pressed.

Maps Roland Juno-60

Juno series

Roland Juno-6 / Juno-60 (1982)
Roland Juno-106 (1984)
Roland Alpha Juno 1 / Alpha Juno 2 / MKS-50(19" Module) (1985)
MKS-50 (19" version of the Alphas) (1986)

There have since been many more Synthesizers under the Juno name, like the Juno-G, Juno D, Juno Di, Juno DS61/DS88, JU 06. Those are based on digital synthesis as opposed to the analog nature of the original Junos.

src: www.rlmusic.co.uk

References

Roland JUNO-60 image (#1489580) - Audiofanzine