OPFXS Twin Boost User manual

TWIN BOOST
Rev 0
opfxs.com
The Twin Boost has 2 independent gain stages which can be set to work together (JOINT) or individually (SEPARATE).
Essentially there are 3 modes of operation:
1) JOINT + PRESETs: channels always have the same gain and it’s possible to save and recall presets.
2) JOINT + GAIN STEP: channels always have the same gain which is handled with GAIN STEP function.
3) SEPARATE + PRESETs: gain of channels can be set individually and it’s possible to save and recall presets.
USE THE PEDAL IN MONO with NO SECONDARY CHANNEL
Any of the 3 modes will do it but JOINT is suggested.
1. JOINT + PRESETS
When set to JOINT the amount of gain will be applied to both channels equally and it’s possible to save presets.
STATUS LED color: PINK
F1 button:
-Long press: set the MIDI channel from 0 to 16. More on this in MIDI section.
oAfter long press the DOT digit in the numerical display will turn on
oYou can now set with CONTROL knob a value from 0 to 16.
oLong press again to save the selection, the display will blink a couple of time to confirm and dot digit will turn off
oShort press to exit without saving, the dot digit will turn off
F2 button:
-Short press: toggles between 2 or 3 presets. When pressed the preset LEDs will blink a few times.
-Long press: go to GAIN STEP mode
PRESET footswitch:
-Long press: save preset on the current position (I, II or III), current preset LED will blink to confirm
-Short press: change preset
To save a preset to the desired position (I, II or III), short press PRESET footswitch until reach the position, move the knob
and long press the footswitch. The current preset LED will blink a few times to confirm.
The display will turn off if no preset is saved in the current position.
To recall next preset just press the PRESET footswitch.
BYPASS footswitch:
-Bypass both channels. The main channel (TIP) has relay true-bypass; the secondary channel (RING) has buffer-
bypass.

2. JOINT + GAIN STEP
GAIN STEP mode is only available with JOINT channels function. In this mode you can set the gain of the channels with
GAIN STEP footswitch. You can also set gain and time factor.
STATUS LED color: BLUE
F1 button:
-Set a new TIME FACTOR from 0 to 99. Zero means an immediate change, values above zero will make gain changes
to happen gradually.
Example:
When set to 90 the gain increase/decrease time will take 900ms for each decibel to change.
When set to 10 the gain increase/decrease time will take 100ms for each decibel to change.
Essentially multiply the TIME FACTOR by 10 milliseconds.
oAfter long press the DOT digit in the numerical display will turn on
oYou can now set with CONTROL knob a value from 1 to 99.
oLong press again to save the selection, the display will blink a couple of time to confirm and dot digit will turn off
oShort press to exit without saving, the dot digit will turn off
F2 button:
-Short press: set a new GAIN FACTOR from 1dB to 28dB.
oAfter long press the DOT digit in the numerical display will turn on
oYou can now set with CONTROL knob a value from 1 to 28.
oLong press again to save the selection, the display will blink a couple of time to confirm and dot digit will turn off
oShort press to exit without saving, the dot digit will turn off
-Long press: return to PRESET mode
GAIN STEP footswitch:
When pressed once the gain will increase of one step according to GAIN FACTOR. If TIME FACTOR is set slow enough (high
value) you can press the footswitch again to stop gain increase.
When kept pressed the gain will decrease of one step according to GAIN FACTOR. If TIME FACTOR is set slow enough (high
value) you can release the footswitch again to stop gain decrease.
3. SEPARATE + PRESETS
When channels are set to SEPARATE the amount of gain for each channel can be set individually. It can be useful if you
want to use the Twin Boost in different spots of your signal chain.
STATUS LED color:
-RED when main channel (TIP) is selected
-BLUE when secondary channel (RING) is selected
F1 button:
-Toggles between main channel and secondary channel.
The main channel is identified by the red LED status. It’s carried by the TIP of the jack.

The secondary channel is identified by the blue LED status. It’s carried by the RING of the jack.
You can switch between channels with F1 button to check and set gain for each channel.
Save a preset:
-Short press PRESET footswitch to navigate to the desired preset number
-Select the main channel with F1 button*
-Set gain with control knob
-Select the secondary channel with F1 button*
-Set gain with control knob
-Long press PRESET footswitch to save
* Order of channel selection is not important, you can select main first or secondary first, there’s no difference.
To recall a preset just press PRESET footswitch to navigate between them. The display will show gain for current selected
channel. You can use F1 to check gain for the other channel.
F2 button: Toggles between 2 or 3 presets.
HOW TO TOGGLE BETWEEN JOINT AND SEPARATE
Short press BYPASS footswitch and F1 together. The yellow LED above the display will blink a few times.
It’s not possible to jump from JOINT + GAIN STEP mode to SEPARATE + PRESETs and vice versa. The commutation has
always to be done between JOINT + PRESET and SEPARATE + PRESET
CONNECTIONS
MONO (no secondary channel): connect TS mono jacks on input and output
STEREO (JOINT or SEPARATE): connect a TRS to TRS stereo jack on input and output. If you want to route the signal to
different spots in your signal chain connect a TRS to TS-TS (Y cable) to input and/or output.
MIDI
MIDI INPUT CHANNEL:
-When set to 0 (omni mode), the pedal will listen to all channels from 1 to 16
-A value of 1 to 16 means that the pedal is receiving MIDI messages only for that specific channel
List of MIDI messages:
CC message
CC data
Description
0
0-127
0 = bypass both channels
1-127 = turns off bypass on both channels
1
0-127
Set gain of both channels (not in dB)
2
0-28
Set gain in dB of both channels
3
0-127
Gain of TIP channel (not in dB)

4
0-127
Gain of RING channel (not in dB)
5
0-28
Gain of TIP channel in dB
6
0-28
Gain of RING channel in dB
7
0-127
0 = Mute the pedal
1-127 = turns mute off
8
0-99
Set TIME FACTOR (any data above 99 will return 99)
9
1-28
Set GAIN FACTOR in dB
10
0-127
step UP gain
0 = will stop the gain increase
1-127 = will start gain increase
11
0-127
step DOWN gain
0 = will stop the gain decrease
1-127 = will start gain decrease
SPECS:
Input Impedance on both channels: 1M ohm
Supply voltage: 9V negative center polarity
Current Absorption: 120mA