I have the preamp from a Peavey Fury VI going into a Brownsville with two J-style pickups. Knobs are volume/blend/low/mid/high. Each pickup has three leads coming off of it; a red, a white and a shield. I have a hot from one and a neutral from the other going to the blend knob. The remaining four (both shields and the other respective wire from each) are all joined at the jack. Is this correct? Where do I ground the battery? Sorry, I'm a newbie at this.