Overview
The GRX4 has been designed to operate in one of two
modes. Program Change mode allows the GRX4 to be
used with MIDI footcontrollers that can only transmit MIDI
Program Change messages or have run out of Control
Change messages... Control Change mode is geared
towards MIDI footcontrollers that have instant access
switches and are capable of transmitting MIDI Control
Change messages. The GRX4 has four (4) Control
Change modes, CC1 - CC4.
When operating in Program Change mode, the GRX4 will
respond to MIDI Program Change messages on the user
selected MIDI Channel. The loops will either be latched or
momentary, depending on the “Edit Loop Configuration”.
All MIDI Control Change messages will be ignored.
When operating in one of the four Control Change modes,
the GRX4 will respond to MIDI Control Change messages
on the default MIDI Channel. The MIDI Program Change
Channel and Loop Configuration will be cleared and
disabled, all Program Change messages will be ignored.
Basic Operation
Connect a MIDI footcontroller and the effects and/or amp
to be routed/switched/controlled to the GRX4 as described
in the “Connections” section.
Apply power to the GRX4 first, then to the effects and
amp. Ensure the effects are active and use the MIDI
footcontroller to access the four loops... When done,
remove power from the amp and effects first, then from the
GRX4.
To edit a preset in Program Change mode, select the
preset to edit using the MIDI footcontroller. Press and/or
hold the
EDIT
switch until the desired combination of loops
(on/off) is selected. The preset is automatically stored in
the GRX4’s EEPROM memory. As a safety feature, only
the LEDs will change when holding the
EDIT
switch down.
The loops will switch after the
EDIT
switch has been
released.
!!ATTENTION!!
ON POWER-UP, ALL LOOPS ARE OFF (BYPASSED).
ON POWER-UP, IN PROGRAM CHANGE MODE, THE
EDIT SWITCH HAS NO EFFECT UNTIL A PRESET IS
SELECTED USING THE MIDI FOOTCONTROLLER.
THE EDIT SWITCH HAS NO EFFECT WHEN IN ONE OF
THE FOUR CONTROL CHANGE MODES.
Edit Program Change Channel
This allows the selection of which MIDI Channel the GRX4
will receive MIDI Program Change messages on.
Power-off the GRX4. Press and hold the
EDIT
switch and
apply power to the GRX4. Wait for all the LEDs to flash
one time and release the
EDIT
switch. You are now in
“Edit Program Change Channel”. Pressing the
EDIT
switch
will allow you to scroll through the sixteen different MIDI
Channels. To save your selection in the GRX4’s EEPROM
memory, simply power-off the GRX4.
Channel #10
Channel #11
Channel #12
Channel #13
Channel #14
Channel #15
Channel #16
Channel #9
CHANNEL
L4-LED L3-LED L2-LED L1-LED
Channel #1
Channel #2
Channel #3
Channel #4
Channel #5
Channel #6
Channel #7
Channel #8
Edit Loop Configuration
This allows the selection of which loops are latched and
which are momentary, when in Program Change mode.
Please note that the ability to make loops 1 - 3 momentary
has been included for customization purposes only.
Typically, only Loop 4 might need to be configured for
momentary switching if used as a control function...
Power-off the GRX4. Press and hold the
EDIT
switch
and apply power to the GRX4. Wait for all the LEDs to
flash two times and release the
EDIT
switch. You are now
in “Edit Loop Configuration”. Pressing the
EDIT
switch will
allow you to scroll through the different loop configurations.
To save your selection in the GRX4’s EEPROM memory,
simply power-off the GRX4.
CONFIGURATION L4-LED L3-LED L2-LED L1-LED
L4/3/2/1 Latched
L4 Mom & L3/2/1 Lat
L4/3 Mom & L2/1 Lat
L4/3/2 Mom & L1 Lat
L4/3/2/1 Momentary
Edit Operating Mode
This allows the selection of the GRX4’s operating mode.
Power-off the GRX4. Press and hold the
EDIT
switch and
apply power to the GRX4. Wait for all the LEDs to flash
three times and release the
EDIT
switch. You are now in
“Edit Operating Mode”. Pressing the
EDIT
switch will allow
you to scroll through the different modes of operation. To
save your selection in the GRX4’s EEPROM memory,
simply power-off the GRX4.
MODE
L4-LED L3-LED L2-LED L1-LED
Program Change
Control Change CC1
Control Change CC2
Control Change CC3
Control Change CC4
MIDI Implementation
Model & F/W:
GRX4
Version
2
Revision
5
MIDI Channel:
Default:
16
1
(Received)
Changed: 1 - 16
2
Control Change:
80 - 83
3
L1 - L4 Latching
(Received)
104 - 107
3
L1 - L4 Momentary
84 - 87
L1 - L4 Latching
108 - 111
L1 - L4 Momentary
88 - 91
L1 - L4 Latching
112 - 115
L1 - L4 Momentary
92 - 95
L1 - L4 Latching
116 - 119
L1 - L4 Momentary
Control Value 0 = Off
Control Value 127 = On
Program Change:
1 - 128
Selects memory
(Received)
locations 1 to 128
Notes:
1. Fixed for Control Changes.
2. User selectable for Program
Changes, stored in EEPROM.
3. The GRX4 is shipped from the
factory in Control Change CC1
operating mode.
4. For DMC Ground Control users:
CC1 = GCX#1 Loops 1 - 4
CC2 = GCX#1 Loops 5 - 8
CC3 = GCX#2 Loops 1 - 4
CC4 = GCX#2 Loops 5 - 8
CC1
CC2
CC3
CC4
