500 Series Preamps:500 Series preamps come in the form of tube modules, solid-state modules, modules that duplicate the circuitry in vintage units, and units tuned for special applications. Whatever type of mic preamp you want, it’s probably available in a 500 Series module. Most of these preamps provide 48V phantom power and include a hi-Z instrument input. You can choose between transformer or transformerless designs, and tube or solid-state models. Some 500 Series preamps add EQ and dynamics processing, becoming true channel strips.