Over here, I'm using a MOTU 828mkii as the interface for CV/G/T work. Ableton CV Tools is the source in those cases. If you have the room to put in a 1U rack device or two, that would be my recommendation. Just MAKE SURE that the interface is DC-coupled (all of the Expert Sleepers modules are) so that it can send/return subsonic data. This method is also cheaper than an E.S. module in that audio pros consider early digital interfaces to be "obsolete", so they're dumping these for dimes on the dollar.