actually i try to get my Tascam US2400 Controller work with Ardour 5.12.
In the Controller Menu i have set Mackie Control with two extenders.
Success! The First 24 Faders are working.
But unfortunately the Master-Control Fader does not move.
After Ardour 5.12 was released, Ben Loftis of Harrison Consoles added dedicated support for the US2400. There are a few details of the way the device works that depart from “normal” Mackie Control surfaces (to the extent that any of them can really be considered “normal” or “standard”). It may be possible to tweak up the “device” definition file to make it work a little better, but going forward, the dedicated US2400 support will be the official way to use this device with Ardour.
Unfortunately that path doesn’t help you right now.