Audio Amplifier ICs (integrated circuits) is a type of audio amplifier that is built into the chassis of the main product. More generally, audio amplifiers are devices that increase, control and amplify the audio signal strength, or amplitude, of audio signals, to make the sound louder and premium quality.IC Audio amplifiers are useful because they can vastly decrease the size of amplification devices, making it possible to create sophisticated amplification within a small package. Unlike power amplifiers, they are not standalone devices.What are the IC audio amplifiers used for?Audio amplifier ICs are used in a range of commercial products. They are found in car stereos, televisions, electronic keyboards, and many other devices in which amplification capacity is in-built.Types of audio amp ICsAudio amplifier ICs can be differentiated by several traits: amplifier type, such as digital, operational, or headphone amps maximum power, in watts, depending on the size and scope of amplification you need input and output signal type, depending on whether you want stereo or mono sound
Obviously there are huge number of audio ICs available in market. Some have obsolete now and many new technogies have arrived. Class D, G, H amplifiers are now common in market with very good efficiency. the list is endless.
You can have a list of common class AB audio amplifiers in the PDF below.
Now there available BJT based audio amplifiers too.Below are some popular transistors. Popular transistors are 5200/1943 pair, 3055/2955 pair, etc. also popular are 2n3773. They can dissipate large power and are easily replacable. professional class G/H amplifier uses such transistors and mosfets to provide high power.
Some points to keep in mind while designing audio amplifiers
Always read Datasheet before using a particular IC or transistor and don't blindly copy other's design.
Use large capacitor banks and always prefer good transformers with sufficient high current rating (depend on your amplifier)
Design Star Grounding and avoid long power tracks on PCB.
Use Zobel,Theile Networks and Boucherout Cell
Use audio rated capacitors,metal film resistors and log potentiometer
Use thick wires and heatsinks with heatpaste
Large capacitor to be used at power supply and should be placed as close to the amplifier as possible
An Active crossover made using Opamps and testing it using LA4225 amplifier with different types of speakers(Woofer and tweeters) Audio IC amplifiers