Inspired by the popular channel and 207D preamps. The DUAL RPA 500 features the Aphex patented Mic-Limiter technology from the 207D and 1788A that works before the preamp. With the limiter on, it is nearly impossible to clip the input of the preamp. Front panel 10megaohms, 1/4-inch inputs for the connection of instruments like guitar and bass. These inputs override the inputs on the rear of the receiving frame when connected.