Check the listing for details. Heritage Audio i73 Pro Edge USB Audio Interface. Condition: Very Good - Refurbished. Listed at 989.10 USD. Vintage Sonics, Cutting-edge DSP, and ADAT Lightpipe Heritage Audio’s i73 Pro Edge is a USB-C audio interface with two classic 73-style preamps, line and instrument inputs, and eight channels of ADAT Lightpipe I/O. Taking inspiration from the legendary British “73” console module that wrote the book on characterful mic preamplification, the i73 Pro Edge leverages old-school transformer-balanced, pure Class A circuit topologies to deliver the assertive vintage-flavored sonics that made the originals sought after by discerning audio pros for over half a century. Painstakingly developed over the course of two years by a talented team of musicians, producers, and engineers, the i73 Pro Edge is packed with sophisticated features aimed at the modern DAW-based studio.