Hi. I have asked around and looked around without any luck to find a device that you can plug a set of earbuds with a 3.5mm stereo plug into that can control the output volume of both left and right channels independently from the stereo output of a radio, ebook etc. Many radios etc these days come with a stereo socket but only one volume control for both channels. Some stations broadcast with the volume uneven and it's quite annoying. Any help would be grateful.
TIA