The last of the Classical Juno series, mostly aimed at low-cost target.
It features some interesting hybrid analog & digital characteristics with Midi interface and memory.
KEYBOARD features 49 keys with no Velocity nor Aftertouch. The main panel has 38 membrane buttons + single jog wheel "Alpha Dial" for data entries: just a few knob for edit... definitively NOT an easy job! however there are 4 shortcuts functions "TONE MODIFY" for direct access to some parameters like Envelope Attack, Brilliance VCF-Cutoff, Modulation Depth and Modulation Rate.
On the left side board has a Joystick that works as Pitch bender and Modulation (pushing forward). Just nearby some buttons dedicated to performance acting labeled Octave Transpose, Portamento Switch and Chord mode memory (outputs also MIDI notes). Back panel has the following connection: Midi and Tape interface, Stereo output, headphones jack and three pedals inputs for Volume pedal for expression (Volume, Aftertouch and Dynamics), two footswitches for HOLD and an assignable functions (PatchUP, Portamento and Chord memory).
Power supply AC is external with 2-prongs connectors.
VOICE based on a main CPU Intel 8032AH that manages 6 voices. Each voice has a single DCO with variable octave range from 4' to 32' based on custom Roland IC MB87123P-G which is able to layer and mix various waveforms: the result is a bit quite weird raw sound with some digital background, but not necessary a bad point.
Let's deep the waveforms sections:
- Pulse: 3 different shapes, the last one has Width adjustment.
- Sawtooth: 5 different shapes with PWM.
- Sub-oscillator: Pulse or Saw waveforms with 1 or 2 octave lower.
- White noise: just control on mix Volume.
LFO a single modulator assignable to VCA and VCF- each destination has individual Depth but they share same rate frequency. Just one parameter for modulation engage delay time.
ENVELOPE one EG for Amplitude and Filter with Polarity inversion or driven by Dynamics (expression pedal). EG has 4 stages segments + 3 time levels called "AABBDSR" with Key Follow (keytracking) function for Amplitude compensation over octaves.
FILTER Multimode analog resonant filter with CPU quantised values based on six IR3R05 (same found Jx10 jx8 or Mks70). The Alpha filter structure features a 4 poles LowPass + High-Pass (only 4 fixed rates values).
EDIT main panel is poor, but there is a full Midi Exclusive system implementation - edited by computer software or directly using the dedicated optional programmer model "Pg-300"; sadly this extra hardware seems to be hard to find and sometimes could reach higher price than an Alpha synth.
EFFECT section features an analog stereo Chorus based on traditional MN3101 - MN3009 (like Juno 60 or Jx3p) with adjustable rate in a good old Roland fashioned way: the chorused sound floats around your speaker using stereo outputs.
MIDI basic Control Changes parameters but a pretty decent Midi buffer (for sysex).
MEMORY holds up to 64 ROM sounds + 64 RAM ones; no way to expand memory in any internal or external media. All internal settings are memory backup on a lithium CR-2032 soldered to the mainboard. Updated alpha Juno II have cartridge facility called M64-C (the same found on tr-707, jx10, mks-80).
lithium CR-2032 battery
RELATED MODELS :
- Alpha Juno 2 - is bigger with 5 octave keyboard Velocity and aftertouch sensitive keyboard.
- HS-10 - an alpha juno1 with different case.
- MKS-50 1 rack unit with some enhancements like Detuning, Portamento and a double RAM memory.
- PG-300 programmer compatible with all the JUNO series.
if you have some cool J1 recordings, consider sharing them. Thanks