Early models of µTune were unfortunately shipped with a badly calibrated CV-Input.
This only concerns you if you have one of the early models with HW version 16 or 17. And only if you have firmware version 1.00 installed.
If you have Hardware version 18 or higher or firmware 1.01 or higher, you can stop reading now.
You can check hardware and software versions by looking at the µTune boot screen.
The µTune boot screen shows the firmware version (FW) and hardware version (HW)
If you have hardware version 16 or 17 and firmware version 1.00, you will need to perform the following easy steps in order to fix the CV input:
a) Install Firmware version 1.01 or higher.
Just download the latest firmware, put the file on the SD card and select ‘Firmare Update’ from the MISC->Expert menu.
b) Perform an input calibration.
You only need to do this once. Connect CV1-in to CV1-out, connect CV2-in to CV2-out. Use short patch cables if possible. Go to Config->Misc->Expert and press ‘Run ADC Cal’. An automatic input calibration will be performed and calibration values saved.
c) Enjoy your new linear µTune CV inputs