This active DI, designed by Bo Hansen in the 1975, has recently enjoyed a second life as an active project with PCBs being produced and a good amount of discussion on the GroupDIY forum. PCBs, self-etching papers, and a bill of materials are currently available from numerous sources (see below).

Notable Features:

• Active design with transformer output
• Phantom powered
• Accepts Lundahl, Haufe, and OEP transformers directly

Price: 16€ for a set of two PCBs

More information:

• Bo Hansen’s personal website
• The GroupDIY thread.
• PCBs available from PCB Grinder.