Thank you very much for posting these instructions greenmachine. My question for you is if this homeade battery module will work with the Sound Professionals SP-BMC-2 microphones, seen here: http://www.soundprofessionals.com/cgi-bin/gold/item/SP-BMC-2 I was hoping to use them, the DIY battery box, and then plug into the line in on my Sharp MD MT-90. Also, I noticed my MD recorder has an optical in, is there any way or benefit to do an optical out on the battery module? Thank you in advance for any responses.