The LaChapell Audio Model 583s was the world’s first vacuum tube mic preamp with D.I. designed for the 500 series format. It is the only 500 series module to properly power the tube with 250V of TrueTube™ technology. Cinemag and Jensen transformers. Unlike some other 500 series format vacuum tube mic preamps, we do not starve the tube of voltages in any way. And since this all occurs within the 583 module, there is no worry of harming your 500 series power supply. With dual drive knobs to separately drive the input and output, the 583S provides total flexibility to explore a broad sonic pallet enhancing its versatility for all of your recordings.