I finally figured out how to power the Sennheiser MKH-104, 404, and 804 from 48 V phantom power (P48) which is very common on professional and many prosumer mixers and recorders. The MKH-X04 series requires -8V for operation. Please note that some portable recorders do not generate P48 even on their XLR connectors. This will not work with P12 or P24 inputs. It works like a charm on P48 inputs (at least from Mackie, Yamaha, and Sound Devices). Thanks to everyone for their input and assistance.