Some bassists use separate preamplifier/power amplifier setups, where one or more preamplifiers drive one or more power amplifiers. In the latter example, a bass player can use a bass-specific power amplifier or use a sound reinforcement system power amp.
Bass players often employ separate preamplifiers and power amplifiers; in some configurations, a player might opt for a dedicated bass-specific power amplifier or utilize a sound reinforcement system's power amp.