Trouble Recording VHS Tapes & Audio with USB Video Converter

I am trying to copy VHS video tapes to my iMac. I bought the most common RCA/S-video capture device that plugs into USB ports. When I plug the device into my USB port, I can see it show up as an input option for many applications (OBS, QuickTime Player, Piezo, Audio Hijack, VLC, and even the Apple>System Preferences>Sound). Its name displays as “ AV TO USB2.0 ”. The video input works perfectly, but the audio has a constant background sound level of 0db on all audio meters. I can’t hear any background sound, but it overwhelms the sound I am trying to input. I have tested this on OS 10.6, 10.12, and 10.13, but results are the same. I would like to find a way to use this device as intended though my USB port. I do have a work-around where I can import the left & right audio through my Line-In jack and combine it with the video later, but there should be a simple way with this single USB video converter.