ROLAND JUNO-106 - The Digital/Analog Synthesizer That Stood the Test of Time

The year 1984 was a pivotal moment in the world of music. Roland introduced the Juno-106, combining analog power with digital precision, redefining the possibilities of modern synthesis.

The Juno-106 followed the success of the Juno-60, but introduced key improvements in MIDI connectivity, memory features, and practicality for studio production. Thanks to its simple interface and iconic sound, it became one of the most widely used synthesizers of its time—its influence remains undeniable even today.

Revolution in User-Friendliness

Before digital control became mainstream, analog synthesizers were often unstable, difficult to operate, and required manual adjustment of all parameters. The Juno-106 eliminated these barriers, offering a clear, intuitive design.

Key Revolutionary Features

•  Digitally Controlled Oscillators (DCO) – A combination of analog sound and digital stability.
•  Full MIDI Connectivity – Allows seamless integration with external sequencers and DAWs.
•  Preset Memory Slots – Pre-programmed sounds that could be quickly recalled.
•  Well-Laid-Out Controls – Facilitates easy sound shaping without complex menus.

The Juno-106 provided professional sound combined with simple operation, launching it into studios and live performance setups around the world.

Sound Architecture – Analog Character with Digital Control

Although the Juno-106 uses digitally controlled oscillators, its signal path remains fully analog, giving it depth and organic warmth that pure digital synthesizers cannot replicate.

Key Elements of Its Architecture

•  6-voice polyphony – Ideal for rich pads, lush synth textures, and layered sounds.
•  Digitally Controlled Oscillators (DCO) – Maintains stable tuning, unlike voltage-controlled
   oscillators (VCOs).
•  Analog Resonant Filter (24dB/oct low-pass) – Warm, expressive tone, favored for various
   synth sounds.

Built-in stereo chorus – Adds width and depth, a signature element of the Juno series.

The Juno-106 balances analog expressiveness with digital precision, making it an ideal studio instrument.

Unique Filter Resonance

The Juno-106 filter is smooth, musical, and resonant, but differs from its predecessor, Juno-60.

How Does the Juno-106 Filter Differ from the Juno-60?

•  Juno-60: OTA-based filter – Warm, organic response, but less digital control.
•  Juno-106: Curtis-chip filter – Sharper resonance, distinctive character.
•  Resonant self-oscillation – At high resonance levels, the filter can generate sound independently.
•  Using the KYBD control, the filter cutoff can track the keyboard, allowing for higher harmonics
   to be heard on notes with higher pitches.

Many musicians love the versatility of the Juno-106 filter for its distinctively smooth texture and deep sonic power.

The Juno-106 was also equipped with a non-resonant high-pass filter (HPF), with four control positions and a dedicated slider for cutoff frequency.

MIDI Connectivity – A New Standard in the World of Synthesizers

The Juno-106 was one of the first polyphonic synthesizers to feature full MIDI compatibility.

What MIDI Enables:

•  Sequencing – Easy integration with hardware or software sequencers.
•  Parameter Automation – Filter, oscillator, and modulation can be controlled directly from a DAW.
•  Synchronization with External Gear – Connects with drum machines and other synthesizers.

With the ability to transmit slider and button information via MIDI using System Exclusive (SysEx) messages, the Juno-106 has become a studio favorite, ensuring its long-lasting presence in music production.

Curtis Chips in the Roland Juno-106

The Juno-106 relies on Curtis chips, specifically 80017A, which play a crucial role in its sound architecture. These chips combine VCF (filter) and VCA (amplifier) into a single integrated circuit, providing a compact design and its signature tonal response.

Why Were Curtis Chips Important?

•  Integrated design – Combining filter and amplifier into one chip allowed for a streamlined
   synthesizer layout.
•  Distinct resonance – Curtis chips give the Juno-106 a smooth, musical filter, ideal for pads,
   synth plucks, and ambient textures.
•  Analog response – Despite digitally controlled oscillators, Curtis chips preserve a fully analog
   signal path.

The Problem of Curtis Chip Degradation

Unfortunately, Curtis 80017A chips have a well-known issue with material degradation, causing voice circuit failures over time.

Main Causes of Failure

•  Epoxy coating – Chips were encased in epoxy, which cracks over time, leading to oxidation
   inside the circuitry.
•  Temperature fluctuations – Prolonged use and heat exposure accelerate chip breakdown.
•  Aging components – After decades, the conductive layers within the chip deteriorate, resulting
   in lost voices.

How to Identify Faulty Curtis Chips?

If a Juno-106 starts losing voices, it is likely due to VCF/VCA chip failure. Common symptoms include:

•  Silent notes – One or more voices stop working.
•  Distorted sound – The filter or amplifier produces unusual distortion.
•  Random voice dropouts – Sounds intermittently cutting out or sounding weak.

Replacement with Modern Replicas of Curtis Chips

Due to aging problems with original Curtis 80017A chips, modern alternatives have been developed to offer more reliable performance and longer lifespan.

New Versions of Curtis Chips

•  OnChip Systems, the official holder of the original Curtis designs, produces authentic chips that
   match the original specifications.
•  Coolaudio (Behringer) manufactures alternative Curtis circuits, often used in vintage synthesizer
   replicas.
•  Restored original chips – Some technicians remove the epoxy coating from old Curtis chips,
   repair oxidized connections, and restore functionality.

Benefits of Modern Replacements

•  Preserves the sound character – New chips replicate the warm and musical filter, central to
   the Juno-106 sound.
•  More durable materials – Modern versions avoid epoxy encapsulation, eliminating degradation
   issues.
•  Long-term stability – Updated manufacturing techniques ensure better reliability and longer
   lifespan than original chips.

These options make it possible to fully restore a Juno-106 without relying on rare vintage Curtis chips.

Synthesizers Competing with the Roland Juno-106 in the Mid-1980s

In the mid-1980s, several synthesizers shared similar features with the Roland Juno-106, positioning themselves as direct competition. These models featured polyphony, MIDI connectivity, and analog or hybrid sound architecture, each with its own unique sonic traits.

Notable models include:

•  Korg Poly-800 (1983)
•  Korg DW-8000 (1985)
•  Yamaha DX7 (1983)
•  Yamaha DX21 (1985)
•  Sequential Circuits Six-Trak (1984)
•  Sequential Circuits Max (1985)
•  Sequential Circuits Multi-Trak (1985)
•  Ensoniq ESQ-1 (1986)

Iconic Songs Featuring the Juno-106

The Juno-106 appeared in numerous legendary songs, where its warm analog sound played a crucial role.

Notable tracks include:

•  Madonna – Like a Prayer
•  Daft Punk – Around the World
•  The Prodigy – Out of Space
•  Depeche Mode – Enjoy the Silence

Artists Who Used the Roland Juno-106

The Juno-106 became a favorite tool for musicians across different genres, thanks to its analog sound and digital control. Prominent artists include:

•  Frankie Goes to Hollywood
•  Vince Clarke
•  Leftfield
•  Liam Howlett (The Prodigy)
•  Junkie XL
•  Moby
•  Paul van Dyk
•  William Orbit
•  Carl Cox
•  Underworld
•  Laurent Garnier
•  Alicia Keys
•  Madonna
•  Vangelis
•  Boards of Canada
•  Tame Impala

Conclusion

The Roland Juno-106 is a unique analog synthesizer, bringing a new level of sound design through digital control, full MIDI connectivity, preset memory, and a legendary chorus effect. Its warm sound, ease of use, and studio versatility secured its legendary status among electronic musicians. Even today, the Juno-106 remains highly sought after for its distinctive tonal character, rich modulation options, and iconic chorus effect, beloved by generations of artists.