Randall V2/T2 MIDI
Amplifer
Receiver
1
Functional Details
On power-up only the Mute output will be on, the other five outputs will be off. The MCU will then quickly check the
EEPROM flag bit to see if it’s the first time being powered, if so it will proceed with initializing the EEPROM, if not the
MCU will then check to see if the Channel Select/Pgm. Store switch is being pressed/held-down (by an end user to select
a different MIDI Channel – see the MIDI Channel Selection section for details). If the Channel Select/Pgm. Store switch is
NOT being held-down all five LED’s will turn on and remain on for 2 seconds (to allow the end user to verify they are
functioning properly). After the 2 second LED test/delay, all the LED’s will turn off with the exception of the Channel 1 LED
and the Channel 1 output will turn on. Then 2 seconds later the Mute output will turn off – the amplifier is ready to go…
Pressing & releasing the FX Loop switch will toggle the FX Loop output and LED on and off.
Pressing & releasing the Graphic EQ switch will toggle the Graphic EQ output and LED on and off.
Pressing & releasing the Channel Select/Pgm. Store switch will change the channel from 1 to 2, pressing & releasing
again 2 to 3, and again 3 to 1, and once again 1 to 2...
When Channel 1 is on, the Channel 1 output and LED will be on, and the Channel 2 and 3 outputs and LED’s will be off.
When Channel 2 is on, the Channel 2 output and LED will be on, and the Channel 1 and 3 outputs and LED’s will be off.
When Channel 3 is on, the Channel 3 output and LED will be on, and the Channel 1 and 2 outputs and LED’s will be off.
When the Channel Select/Pgm. Store switch is pressed & released to select a different channel or a MIDI message is
received causing the channel to be changed, the Mute output will immediately turn on. After the Mute output has been on
for 5 milli-seconds, the appropriate channel outputs and LED’s will turn off and on. Then after 10 milli-seconds, the Mute
output will turn off. The Mute output will ONLY turn on for 15 milli-seconds when a channel is actually being changed, for
example - if Channel 1 is on and a MIDI message is received that is supposed to cause Channel 1 to turn on, the Mute
output will NOT turn on since Channel 1 is already on…
If the Mute output is already on as a result of receiving MIDI Control Change #61 (w/Control Value of 127) via the MIDI
input jack, changing channels will NOT cause the Mute output to turn off after the 15 milli-seconds... Only the reception of
MIDI Control Change #61 (w/Control Value of 0) via the MIDI input jack will cause the Mute output to turn off.
ADDED 09/01/05 : When the FX Loop switch is pressed to
turn it (the FX Loop) on or off, or a MIDI message is
received causing the FX Loop on/off status to be changed, the Mute output will immediately turn on. After the
Mute output has been on for 5 milli-seconds, the FX Loop
output and LED will change states. Then after 10 milli-
seconds, the Mute output will turn off. The Mute output will ONLY turn on for 15 milli-seconds when the on/off
status of the FX Loop is actually being changed… If the
Mute output is already on as a result of receiving MIDI
Control Change #61 (w/Control Value of 127) via the MIDI input jack, turning the FX Loop on or off will NOT cause
the Mute output to turn off after the 15 milli-seconds...
Pressing & holding the Channel Select/Pgm. Store switch for 1 second will save the current settings (such as which
channel is on - 1, 2 or 3 and the on/off status of the FX Loop and Graphic EQ) in one of the 128 preset locations in the
EEPROM memory. The preset location used for saving the settings will be determined by the most recent MIDI Program
Change message received via the MIDI input jack. After the 1 second has passed and the user settings have been saved,
all five LED’s should flash (indicating to the end user that the preset has been saved) as follows - on for 400 milli-seconds,
off for 400 milli-seconds, on for 400 milli-seconds, off for 400 milli-seconds, then the on/off status of all five LED’s should
be updated as per the preset. If a valid MIDI Program Change message has not been received via the MIDI input jack
either due to the wrong MIDI Channel, a broken MIDI cable, the MIDI pedal not being connected… pressing & holding the
Channel Select/Pgm. Store switch for 1 second (or more) will do absolutely nothing.
