The 86 usually takes speaker-level inputs and after that converts them to preamp outs. Because you already have preamp outs, you don't need it; you're already past that stage. The TWK 88 (a processor) will get Those people preamp channels and do most just about anything you need with them. https://www.youtube.com/channel/UCP9Gw00CldPUmiu43y7fdWw