The original PS-3300 included a separate pre-MIDI keyboard controller - in fact, the enormous multi-pin connector cable carried individual control signals for each of the 48 keys! The controller keyboard also included additional CV outs for keyboard trigger and gate, a couple of momentary switches, and a joystick.
In adapting PS-3300 for your computer screen, we jettisoned a few things that didn't make sense (like the joystick), and relocated the keyboard CV outs to the bottom of the Master Panel (otherwise the 3D art would've been an awkwardly angled mess).
We also replaced the joystick CV outputs with Pitch Bend and Mod Wheel CV outs, which make far more sense with 99% of MIDI/USB keyboard controllers out there.
Control signals from the keyboard (i.e., a MIDI/USB keyboard controller) are hardwired to the appropriate pitch and envelope destinations, so it's not necessary to patch any cables to play PS-3300. However, the included keyboard CV outs can be really useful and add flexibility.
Pitch Bend- This outputs a voltage between -5V ~ +5V when the pitch wheel or joystick on a MIDI/USB controller is moved. Its output nominally sits at 0V.
Mod Wheel- This outputs a voltage between 0V ~ +5V when the mod wheel or joystick on a MIDI/USB controller is moved.
Keyb Vel Out- This outputs a voltage between 0V ~ +5V corresponding to keyboard velocity (how hard a note is played). Since it's mono only, it is "last-note"priority; that is, the velocity CV is derived from the most recently played note.
Keyboard Gate/Trigger Out Jacks
The gate and trigger out jacks can be potentially confusing, so please read the following paragraphs closely.
The first important thing is unlike most analog synths, PS-3300 uses "shorting" triggers and gates. Keypresses are just like flipping a switch and completing an otherwise open circuit (as opposed to most other synths where trigger and gate circuits are nominally are at 0 volts, and pressing a key sends +5V).
In either type of circuit, a "trigger" is an instantaneous blip, whereas a "gate" stays on (typically, when a key is held down). A trigger is usually used to initiate something that's going to continue on its own. Conversely, a gate keeps something turned on as long as it's "on" - usually an envelope generator as it runs through its attack, decay, and sustain phases. This is important, because patching a trigger to a destination intended for a gate usually results in, "why the ^&* isn't this working?"
In the case of the vintage Korg PS keyboard controller, its three CV outs and Kbd Trigger Select switch all say "trigger," but they are, in fact, mislabeled. The Trig Out Single and Kbd Trigger Select knob/jack are actually gates, but the Trig Out Multiple jack IS a trigger CV. We'll explain why below, but what you need to know is that we changed the panel labels to correctly represent the control signal types. We did not change the nature of the controls signals themselves.
Gate Out Single- Sends a shorting switch signal when a key is held. The signal remains switched "on" until all keys are released and remains on as long as any number of keys are held.
Trig Out Multi- Sends a very brief shorting switch signal every time a key is played, regardless of currently held notes. The intended use of this output is for repeatedly triggering the General Envelope Generator when it's set to Auto (aka, one-shot) mode. In this way, the envelope cycles through all phases every time a note is played.
Keyboard Gate Select and Gate Out jack- This one is very unique - it sends a shorting switch signal dependent upon the setting of the Kbd Gate Select switch and the number of keys currently held.
Keyboard Gate Select setting 0- Switch signals are never sent.
Keyboard Gate Select setting 1- Shorting switch signal sent when a key is held. The signal remains switched "on" until all keys are released and remains on as long as any number of keys are held - same behavior as the Gate Out Single jack.
Keyboard Gate Select settings 2-5- Shorting switch signal is sent only when the corresponding number of keys is currently held.
For example, if the Keyboard Gate Select is set to 3, three notes are simultaneously played, a shorting switch signal is sent as long as three or more notes are currently held. If only one or two notes are currently held, no shorting switch signal is sent.
If you're like us, you're probably wondering, "what the heck would I use that for?" We believe the intention of this "numeric" shorting switch was to connect it to Signal Mixer External Level Control CV inputs in order to control the number of synth layers directly from the keyboard - sort of a 1977 version of bringing in additional layers with velocity.
How to use the Keyboard Gate Select and Gate Out jack
Since that bit above might be a little hard to get your head around, we've built a basic patch to demonstrate how the Keyboard Gate Select sections works:
Click the New button at top left.
In the Signal Mixer section at the top of the Master Panel, set Ch-2 Volume to 8.
On Voice Panel 2, set Scale to 4' and MG1 Intensity to around 1% (we're changing up these parameters in order to make Voice Panel 2 sound noticeably different from Voice Panel 1 - the settings are not critical).
On the Master Panel, set Kbd Gate Select to 3 (next to the big plug), and patch a cable from the Gate Out jack to General Envelope Generator Ext Trigger Input 1.
Patch a cable from the General Envelope Generator Out 2 to the Signal Mixer Ch-2 External Level Control jack.
Try playing single-note lines on the keyboard - only Voice Panel 1 is heard. Now hold down three or more notes on the keyboard, and Voice Panel 2 sounds, one octave higher. If less than three notes are played, Voice Panel 2 isn't heard, but any time three or more notes are played, Voice Panel 2 is audible.
Also notice that every time Voice Panel 2 enters, its level is affected by the General Envelope Generator settings. Increasing the Attack time slows Voice Panel 2's entrance; increasing the Release time causes it to fade out slowly when fewer than three notes are played.
