Roland Alpha Juno 2 (1985)

 

An update from previous budget synthesizer JUNO-1 with a larger and dynamic 61 keys keyboard.

 

KEYBOARD 61 velocity keys with aftertouch.
The main panel features a LCD display, 39 buttons and a jog wheel. On the left side a joystick that acts as both pitch bender and modulation functions.

Rear panel terminal connectors:
- Midi interface
- tape interface
- main out
- headphones out
- expression pedal assignable to volume / aftertouch / velocity
- assignable pedal: patch up / portamento on-off / chord memory on-off
- hold pedalswitch input.

VOICE main CPU Intel 8032AH manages 6 voices polyphony.
Each voice has an assigned DCO oscillator based on custom Roland IC MB87123PG and each DCO is composed 2 summable waveforms + 1 sub oscillator + 1 noise generator:

Waveform	Harmonic variations:	Level	width:	range:
pulse	3	-	yes (3rd shape)	4' 8' 16' 32'
saw	5	-	yes (3rd shape)	4' 8' 16' 32'
suboscillator	5	yes	-	1 / 2 oct below
white noise	0	yes	-	-

 

alpha juno 2 on oscilloscope

 

 

PERFORMANCE some Ju-2 special playmode functions:
- octave transpose keyboard
- portamento glide
- chord mode learn (it outputs Midi)
- bender range 1 octave setting
- key transpose
- 15 aftertouch levels assignable to VCF / DCO / VCA.
MIDI some basic CC# are managed including: modulation, foot control, portamento time
and hold

 

FILTER multimode VCF based on 6 IC X IR3R05 (also VCA).
- lowpass at -24dB/Oct /resonance (it does not auto-oscillate)
- highpass: only 4 preset values.
VCF system provides keytracking system scaled to 15 values

LFO a single delayed modulator and 2 destinations with individual depth values:
- DCO pitch
- VCF filter.

ENVELOPE a single 4-stages + 3 time levels with polarity inversion EG assignable to:
- DCO pitch
- VCF filter cutoff
- VCA amplitude with special gate mode.
In addition the VCA provides a 15-levels keytracking system.

EFFECT section features an analog stereo chorus based on 2 X MN3101 + 2X MN3009 IC like Juno-60 or Jx-3p with adjustable rate

MEMORY:
- 64 ROM presets
- 64 RAM slots + 64 others if optional cartridge m64c is fitted.
Sounds can be saved to magnetic tape or Midi exclusives data dump.
BATTERY REPLACMENT: change lithium battery model CR-2032 soldered to the mainboard.

 

REPAIR the Juno series a pretty reliable on time, with no particular technical issues.
The Juno2 most common problem is the dead keys, which involves cleaning the contacts, please do follow this very useful video:

EDIT main panel lacks many real-time commands, but there are many computer software or it is possible to use the dedicated optional programmer model Pg-300.
- Alpha Juno Control (MAC / free) PIC
- VST AU Alpha JUNO Editor (MAC-PC / $$) PIC
- Soundquest (MAC-PC / $$) PIC
- MKS-50 (Atari ST / freeware now) PIC
- Alphabase (old PC freeware) PIC
- CTRLR (MAC-PC-LINUX / free) pic below

RELATED MODELS :

Alpha Juno 1 smaller version with 49 keys (no velocity) and no cartridge port. MKS-50 rack unit with some enhancements like Detuning, Portamento and a double internal RAM memory. HS-10 - an alpha juno1 with different case. HS-80 it's alpha Juno2 consumer version of with different outfit and powered internal speakers VIDEO PG-300 programmer compatible with all the JUNO series.

 

VST PLUGIN / SAMPLED VERSION there are some free and commercial samples set:

	name	price	link	demo
	PHUTURA	free VST emulation
	SMC Joono VST	free VST emulation
	REDOMINATOR	commercial VST plugin

AUDIO DEMO

SANXION (track overdub) with TR-606 Performance 1 + drum samples Performance 2 + drum samples Performance 3 + drum samples Performance 4 + drum samples Performance 5 + drum samples Performance 6 + drum samples Organ: b3 even more poor Harpsichord: like a 8 bits Piano: analog poor Clavinet: naaaa Bass: funky Bass: mooga Bass: razor Bass: jumpy Bass: soft quiet Bass: attack Drums: analog kit Drums: timpani FX: scary ohhhhohhhh LOL Ambient: chill Ambient: space Ambient: system Pad: murky Pad: chorus Pad: time bandit String: LFO movement String: very simple Synth: WOOObled Synth: what's a hoover? Synth: Drill Synth: droning Synth: melodie d'amour Synth: rate by rate Synth: resonance up Synth: square world Synth: slippery when dry XP: waveforms all pulses XP: suboscillators waves XP: sawtooth width XP: pulse width XP: white noise and filter XP: lowpass and resonance XP: highpass mode filter XP: LFO all shapes XP: Chorus BBD

Soundcloud alpha juno2

VIDEO CLIP SELECTION demo1 demo2 Some Presets