Roland Alpha JUNO
Overview

Architecture

1DCO, 1Sub-OSC, VCF.
1ENV is shared to modulate DCO, VCF and VCA.
Analog Chorus effect.

Alpha Juno Block Diagram
Alpha Juno Block Diagram

Oscillator

Alpha JUNO has 1 DCO, but it produces multiple waveforms at once. There are 4 sound sources: Pulse and Saw are mixed, and 1 Sub-OSC and a Noise generator are added. Below is the image of these waveforms.

Alpha Juno DCO Waveforms
Alpha Juno DCO Waveforms

Compared to older JUNOs, comb-like waveforms are added. Saw wave has PWM, too. The Sub-OSC has several waveforms and can be tuned to 1 or 2 octave lower.

Filter

The analog LPF seems to be 4-pole that can self-oscillate.
There's one static HPF. When HPF is set to zero, it works as low frequency booster.

Envelope

There's only 1 envelope, as all JUNO series are. But there is another option - GATE. By selecting GATE, a simple organ-like envelope is available.

While JUNO had a simple ADSR envelope, Alpha JUNO has 4-stage multi-step envelope.
I heard someone said that this software envelope works slow, but I think Alpha's envelope is very fast enough (See the sound examples page).

LFOs and other features

Alpha JUNO has 3 independent LFOs for Vibrato, PWM and Chorus.
The analog Roland chorus fattens the sound.
Arpeggiator is gone, but the Chord Memory feature is added.
Responds to Velocity and Aftertouch via MIDI.
Responds immediately to the Program Change without envelope retrigger. This is useful for Wavesequence-like timber motion.



Next Alpha JUNO

Deep Synthesis: Home

9. 18. 2005