Hi there Glenn and all.Yes the free VAC is called VB Audio. It is stable and best of all it is free unlike the VAC offered by Eugene (Evgenii) Muzychenko. I have both and use VB audio most of the time as I do not care for Eugene's bed side manner when you are in trouble or need a new key etc.
Anyway, you can monitor the audio even though you are using a VAC by opening up the windows control panel, sound, cable output VB Audio VAC, then you will see 4 option tabs: General, Listen, levels, advanced. Select listen, then look for the small box that says "listen to this device", then check it. Hit ok and close all windows. You will then be able to listen to whatever audio you are porting from your SDR to apps like ARGO etc. 73 Gedas W8BYA