I had the same issue. If you go to the vox website, you can download the drivers you need to get the Cambridge 50 to show up as an audio interface in Studio One. Here's the link -
https://voxamps.com/downloads/ - Then go to Drivers section on the page. I had to install the VOX 2ch Audio Driver for Windows v2.0.0 but once I did, it showed up as an audio interface for me. Hope that helps!