So far we’ve been talking about “integrated” or all-in-one amplifiers.

Another design possibility is to have the amplifier split over two boxes. The smaller box is the part you connect all your source devices to, and it has all the controls (volume, input select, tone, etc). This part is the pre-amp (short for pre-amplifier) which is small and light and doesn’t throw off much heat.

Then there is a larger heavier unit, called the Power Amplifier, which doesn’t have any controls (except a power button) that drives the speakers. This can be placed on the floor, closer to the speakers, away from the rest of the equipment.

In some totally over-the-top installations, there are TWO Power Amps, one for each speaker.