PLUM AUDIO –
ARBA
CHANNEL SENSITIVITY CALIBRATION:
On the back of the module, there are four small trimmers that control the overall gain of each channel.
Use a small screwdriver if you wish to change the default setting. They are single-turn trimmers.
Be
gentle so you can feel when the trimmer is reaching its end
– rotate clockwise to get higher gain or
counterclockwise for lower gain.
You don’t must to use our suggested “calibration procedure”. The best way is to use your ears and set
those trimmers according to your taste.
You even don’t need to set all channels equally, if you want 2 channels with higher gain and 2 channels
with lower gain you are welcome to do so.
If you wish to calibrate all channels equally to get unity between channels, please follow the calibration
procedure.
CALIBRATION PROCEDURE:
First, you need to choose what amount of CV will cause unity gain (unity gain is the point when the input
gain and output gain are equal).
- For super clean and natural low output gain you can use 8V or above.
- For low saturation at high gain you can use 6V-7V.
- For a higher saturation, you can use 5V or less.
1.
Turn off all limiters by moving the four dip switches from the ON position to OFF.
2.
Use a multiplier or stackable cable and insert the same DC source to the audio input and the CV
input of the channel you're calibrating, DC voltage should be at your desired settings (8V for
clean, 6V for low saturated and so on…).
3.
Connect the output to a multimeter or oscilloscope and measure the voltage at the output.
4.
Set the trimmer until the output is approximately equal to the voltage at the input.
5.
Repeat this procedure on the next channel.
6.
When you're done – don’t forget to turn the limiters back to ON.
