based on the
Reproduced with permission
from Paul Maddox
started out as a re-release
of the MIDI2SDS from Paul
Maddox and was called MIDI2SDS (X)
That version, like it's original predecessor, had a limited
TRIGGER output range of
around 2V to around 4V. This limitation was imposed on the module
as a consequence
of some limitations of the MAX529 chip.
and circuit details are here
MIDI2SDS II SchematicMIDI2SDS II FirmwareMIDI2SDS II Gerber Files
NB: These above items cannot be used with the current ELBY Designs offerings
The current revision
of the MIDI-Retrofit-8 utilises the MAX528 8-bit DAC which
allows for a wider
range of output voltages.
MIDI-Retrofit-8 requires a single-rail
supply ranging from 12V to 15V providing for a maximum
output voltage of between 8V (12V supply) and 10V (15V supply).
supports 2 'trigger modes':-
where the TRIGGER output is a pulse generated on receipt
of a valid NOTE ON message
and having a pulsewidth defined
by the onboard trimpot (between 0.5uS and 120mS),
where the TRIGGER output is controlled by the receipt of
valid NOTE ON/NOTE OFF messages.
The logic polarity of the TRIGGER
outputs is also selectable:-
In both cases the maximum amplitude
of the TRIGGER output is determined by the VELOCITY value
of the respective NOTE ON message as a proportion of the maximum
set output voltage.
Settings are common to all
MIDI-Retrofit-8 now supports an optional ACCENT Mode. When enabled, the TRIGGER outputs
are paired up 1-2, 3-4, 5-6 & 7-8
with each pair sharing the same MIDI address.
The first output of each pair responds as normal to its associated MIDI message.
The second output will only trigger when the velocity value is greater than 120.
of Materials for MIDI-Retrofit-8 pcb
Guide User Guide
Midi-Retrofit-8 is also available as a 3U Euro-Module - see ED103 in the Panther section of the shop
The minimal installation
option is to mount the MIDI-Retrofit-8 inside the unit to be controlled,
wiring the TRIGGER outputs directly to the relevant points on
the instrument and connecting to a suitable power supply inside
the unit. The MIDI-IN socket being the only item that requires
to be mounted on the unit for easy access. This option is suited
for installations where the MIDI Note assignments will be set
once (or very infrequently).
The standard installation
optionally brings the LEARN switch out to a user accessible
point as well as installing LEDs to indicate the status of each
of the TRIGGER outputs. During normal use, the LEDs indicate
the status of each TRIGGER output. While in LEARN mode they indicate
which channel is beingh programmed. This is useful if you wish
to change the MIDI Note assignments often and/or desire a visual
indication of the operation of the MIDI-Retrofit-8.
If LED status is
required for programming but is not needed for normal operation
(or you don't want to mount the LEDs on your unit) the MIDI-Retrofit-8
pcb allows for the LEDs to be mounted on the pcb directly.
in conjunction with the onboard LEARN switch, allow the user
to observe the
programming status during the LEARN mode.
Installing in to a Roland CR-8000
The MIDI retrofit-8 being used in a Simmons SDSV courtesy of The SImmons Guy
MIDI-Retrofit-8-1U houses the MIDI-Retrofit-8 module in a lightweight
ABS 19" 1U rack
ready for direct rack mounting, or it can
just as easily be used free-standing.
is powered by a 15VDC 300mA power supply (2.5mm DC connector,
tip = positive)
expands the 8 outputs of the MIDI-Retrofit-8 to 16 outputs
control for most larger drum machines on the market.
PCB V1.7 onwards inclueds a new feature - MODWHEEL. Sending MIDI Control Modulation messages (B1, 01, xx & B1 21, xx) to the MIDI-Retrofit-16 will generate an anlaogue output voltage proportional to the modulation value. In the example below, the output voltage has been connected to the HiHat control on an SDSV (scope image at back of video shows the MODWHEEL output).
The MODWHEEL output applied to a Simmons SDSV HiHat courtesy of The SImmons Guy
The latest addition to the MIDI-Trigger family is the MIDI-Interceptor which takes the MIDI-Retrofit-16
adds a 16-channel Trigger Input Scanner which, in conjunction with new firmware,
allows the MIDI-Interceptor to provide MIDI control of your drum machine in
PARALLEL with the equipments internal controller.
So now you can augment your drum machine by adding your own extra MIDI triggers during a sequence run.
Build GuideUser Guide
this link for examples of the former MIDI2SDS being used to MIDIfy
a drum machine
implement these retrofits you will need:-
1 x MIDI-Retrofit-8 PCB
1 x MIDI-Retrofit-8 Component Kit.
2 items will provide you with the pcb and suffcient components
to dress the pcb.
This also includes the MIDI-IN socket and
a LEARN switch.
Although not required during normal operation it is recommended
that you install
Trigger Output LED's to provide a visual status during the LEARN