Digitnow device on Mac does not show up

[dlminehart]

I have a Digitnow device attaching my VHS player via USB to my Mac Mini running High Sierra in order to convert my VHS tapes to MP4 files. It comes with Maaster AVCap software that has been doing a good job of capturing the video, but completely misses audio from almost all my tapes. All 3 (red, white, yellow) connectors are present, and work fine playing the VHS tapes directly to my TV. OBS was suggested as an alternative. I've set up OBS Studio per instructions in the brief manual, doing the auto-config, using defaults for video sizing, fps, etc. and for audio. I've selected a Video Capture Source. I'd expected to go beyond the generic Video Capture Device to specify my actual device on USB, but the only device option that appears is an OBS Virtual Camera, so I selected it. When I hit Record on OBS and Play on my VHS player, I see nothing in OBS preview, hear no sound, and the saved file is completely empty. Any ideas on how I can get OBS Studio to record from. my USB input of digitized VHS output?

 

[dlminehart]

Correction to the original: after restarting my Mac, the audio capture now works using my Masster AVCap software. However, it has no editing capability, and only saves in .MOV format. I'm still hoping that OBS will recognize my converter box attached via USB as a Video Capture Device and let me import, edit, and save as MP4.