Using USB host connection. I think I read about other devices not being recognized. Hopefully USB host compatibility is on the to do list.
A number of devices out there, the A-49 among them, are not USB class compliant (at all or by default). That means it requires specific drivers to use over USB (with Windows etc) and will not work with a generic device like Hapax. The good news is, the A-49 can be configured to be class compliant, see https://rolandus.zendesk.com/hc/en-us/articles/213565306-A-49-USB-Driver-Setting
Thank you @pmatilai that is very helpful, configuring the A-49 as class compliant did the trick. I thought the A-49 already was class compliant as it was recognized and working fine with my MPC Live using USB.
Interesting. That means the MPC Live is doing extra tricks for compatibility with devices that claim to be non-class compliant. It’s a surprisingly common thing for devices to claim non-compliance but work just fine with the class-compliant driver when pointed to it regardless. The Linux kernel has a long long list of such cases, but this is the first time I see evidence of a special purpose device like the MPC applying these workarounds.
Why vendors do this is totally beyond me - you create a device that would work out of the box on any relevant OS and USB host device, and then you go out of your way to prevent just that?