Re: I need an EMG's wiring expert advise.
To tell you the truth, it's best if you swap out the 5-way switch on your 7620 with a 3-way. Unless you take apart your pickup or unless EMG makes a 7 string version of the EMG 89, a 5 way switch with give only give you 3 working sounds. Neck, Brige and both together. There probably is a way to get more sounds using some fancy electronics but then it's just a pain in the @$$ to work with.