http://www.amazon.com/Digital-Optica...4470221&sr=8-2
E.g. this one. Guess you simply have never focused on the cheapest possible variants as I have to do in this case.
I'm pretty much positive that it's crappy, but the goal is to get any-quality FOH mix (the final sound that goes to the audience through the venue's speakers) in my ears while I'll be able to process my own and my bandmate's guitar signals through Pro Tools and directly into the mixing board through Mbox's main outputs - sure I'll need an additional A/D converter to get this FOH signal through S/PDIF input (since both analog inputs will be busy with the guitars) into my Mbox first, but it's not a big deal since it'll just require an extra $30.
Or if we decide to use a double track in addition to our live mix I can use just that single D/A converter plugged into S/PDIF output to pass this signal from Pro Tools project into the mixing board while monitoring the FOH signal in a casual way through the venue's onfloor monitors.
Sure the main purpose of purchasing Mbox for me would be a step forward in recording process (for now I get all the job done with a $35 Creative Audigy SE PCI Sound Blaster lol - you can even check a couple of our tracks at the very bottom of this page:
http://vk.com/iscreamrussia), but I'm pretty anxious about moving to the aforementioned live concept so I'm trying to figure how to make it work.