Addaz,
The wiring from the switch to the power supply is correct. From the power supply to the pre-amp there are two wires that need to be switched. They are the ones coming from the +15V / gnd terminals of the power supply.
I have a .pdf file with all the wiring instructions plus pics if you are interested.
Just send an email to jcg0324@aol.com and I will get it to you.
Thanks,
Jack