SSL2+ Audio Interface 4K Switch On and Off Comparison on a House Beat

What is this voodoo? it’s not just a level increase (but that’s apparent) Can anyone let me know what’s the SSL secret under the hood? FYI the beat was programmed from scratch in Maschine which was plugged into channels 1/2 of the SSL2 and set to stereo - you can see the button pressed in at the top right on the monitor mix section and fully counter clockwise to ’input’ (ie not usb)