We all need an audio amplifier to drive our loudspeakers so we are going to discuss the different types available. This is a music site so we will keep this focused on the needs of a project studio. For a typical home studio I recommend an amplifier with around 150W per channel into 4 or 8 Ohms (speaker impedance) 150 Watts per channel will be able to drive most 6.5 inch driver near field monitor systems.When you check out an amplifier try and avoid fan cooled ones as they will add to the ambient noise floor of your studio and this is not desireable. Amplifiers up to 150 watts are typically using passive heatsink cooling without cooling fans.