Here is a diagram of how to separate the preamp and the main amplifires from two Marantz Receivers. That way a person is getting a lot more watts and less chances on frying your amplifires. Also you can have two equalizers one goes to your front speakers and the other equalizer goes to your rear speakers which makes an incredible sound difference. One tip I will give you would to make sure that all you speakers have crossover networks so that all you speakers will last longer