Deckard’s Dream Expander FAQ and Build Guide.
DRAFT V1.5
What Does the Expander do?
The Expander provides both MIDI control changes and/or audio effects, to any sources plugged in.
Effects:
1)
Ring Modulator: Audio Only
2)
Tremolo/Chorus: Audio Only
3)
Delay: Audio Only
4)
Reverb: Audio Only
5)
Sustain I & II: MIDI Only
MIDI
The Expander receives across ALL (1-16) MIDI channels, and outputs only on the channel(s) it receives signals on. Example: If your controller is
sending on channel 4, the Expander will receive all messages on CH4, and send only on CH4. If your controller is set to 2-16 for MPE, the Expander
will send out using corresponding channels 2-16.
Audio
The Expander takes any 2 audio sources and combines them into a single audio signal for effects processing. Balancing the audio levels must be
done before input into the Expander.
How do I update the firmware?
Firmware for the MCU cannot be updated. However, the 3 main audio effects are controlled by individual SPIN FV-1 circuits, and can be augmented
or modified by customizing the 1-8 programs stored on their corresponding EEPROMS. In short, you can replace the EEPROMS with your own
versions.
What does the MCU do?
The MCU takes 4 inputs:
•
MIDI
•
High or Low signal from the Sustain I&II switch
•
0 to 3.3V from the Sustain_Level slider
•
DL_Time signal from the Delay Time Slider
The MCU provides 3 outputs:
•
A CLK signal for the Delay effect. This is used to clock the SPIN FV-1 circuit based on the setting of the Time slider input. This is why this IC
does not use an external timing crystal like Reverb and Tremolo/Chorus do.
•
The Gate signal that is generated from the MIDI input
•
MIDI Control Change messages (CCs) are generated from the settings of the Sustain Level switch and Slider.
What about all the sliders, can I save patches?
Unlike the DD synth, where slider values are stored digitally for patch development and recall, and then converted back to an analog signal or
voltage, the sliders on the Expander are used entirely as an analog signal or voltage. You can’t save settings for patch development or saving.
How do I hook up the Expander to my DD?
There are several ways:
1)
If you want to use the Sustain:
a.
Controller MIDI Out -> Expander MIDI In
b.
Expander MIDI Out to DD MIDI In
c.
DD Audio Out to Expander Audio In
d.
Expander Audio Out to Mixer/Amp
2)
If you just want to use Audio effects:
a.
Controller MIDI Out -> DD MIDI In
b.
DD Audio Out to Expander Audio In (1)
c.
Another synth Out to Expander Audio In (2)
d.
Expander Audio Out to Mixer/Amp
Or even:
a.
Controller MIDI Out -> Expander MIDI In
b.
Expander MIDI Out to DD MIDI In
c.
DD Audio Out to Mixer Line In
d.
Mixer Aux out to Expander Audio In (patched as an external effects send).
e.
Expander Audio Out to Mixer Line In (Patched as en external effect receive).