Welcome to Justanswer.com, my name is Dustin.I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
What specific program is it that you used to convert the VHS to digital format on your mac?
After you installed the program, did you update it?
Also, sometimes if you have the capture device plugged in before Easy VHS to DVD is started, no audio will be outputted. What you need to do is remove the capture device from the USB port, then start Easy VHS to DVD. The software is going to prompt you to insert the capture device. Once you do that, now you can capture audio
Lets try both those steps in order and then let me know whether they worked or not.
I strive to provide great service, and greatly appreciate a 5 star rating clicked and submitted when you are satisfied.. I always answer follow up questions.Dustin S.Senior Technician and Network Switching Systems Operator / Maintainer.