For those who want a ready-made headphone amplifier, I have the Behringer Miniamp AMP 800, which costs me 40 euro when I bought it. Analog input only ...

Thanks Andrea, the Color3Way does the trick. I presume you mean the slider called "values" . I selected "copy to all" of the middle one, then adjusted...

Many thanks Sam, awesome! I wonder if it is worth putting this in the Feature5 manual, it is quite common.