An integrated amplifier has a preamplifier and a power amplifier in a single box. So an AV receiver is an integrated amplifier because you can connect input devices, alter the volume, and power your speakers in a single unit. Some more advanced audio systems will use two separate components – a dedicated preamplifier and a power amp. The preamplifier accepts multiple devices and has a volume control to vary the audio level. Then, the signal is fed to a power amp, which amplifies the audio even more and sends it to connected speakers.