he optional card contains a high spec, low jitter A/D converter and gives the VoiceMaster Pro a 24 bit S/PDIF digital output capable of up to 96KHz sample rate on an RCA phono connector. It has a word clock in connector for syncing to external devices too. Unless your computer has a S/PDIF input built in (some cheaper internal sound cards do) it does not allow you to connect the unit directly to your computer for recording into your DAW - you will need an audio interface/sound card with a RCA S/PDIF input for this (check out the Focusrite Saffire as an example).
There are a few reasons why you may want a digital output from the VMPro:
- cable interference is not an issue with digital signals so no noise will be induced as with an analogue connection, thus the recorded signal will have a slightly lower noise floor.
- the VoiceMaster Pro converter is of better quality than that in your audio interface/sound card.
- all analogue inputs on your interface are being used so you only have the option of connecting to it via S/PDIF.