I just bought a gallien-krueger 700rb-II and a hartke 4.5 xl series cab. I know that the head has a bi-amp mode but I don't know how to use it. Can I use the bi-amp mode with my hartke cab? All it says in the owners manual for the 700rb-II is that to use bi-amp mode you have to turn on the bi-amp switch on the rbh series cabs, but it doesn't show how to use it with other cabs. Thanks for your help.