4×15 watt power amplifier consists of four channels of amplifiers. The core part of the circuit is 15W BTL X 2 channel audio power amplifier IC TA 8215 developed by Toshiba. In this power amplifier circuit, two TA 8215 ICs are used. This is for obtaining four channels that is two channels from each IC. TA 8215 is an IC with power amplifier stages and preamplifier integrated inside it. Pins 7 and 19 are Vcc and pins 13 and 14 are ground of power amplifier stage. Vcc and ground pins should be connected to positive supply and ground respectively. Pin 9 is the Vcc of internal pre-amplifier and Pin 5 is its ground. Vcc is connected to positive supply and ground pin to ground through a 10 ohm resistor which separates input ground from common ground and this improves noise rejection.
In this circuit power supply decoupling is accomplished by 100 uF (C6 and C20) capacitor. High frequency stability in this circuit is achieved by the resistor network connected to the output line of each of the amplifier. Volume controller in each channel is the variable resistors of 10k (R3, R4, R12 and R13). The power supply required for this amplifier is single 12 V DC supply. The maximum output power delivered from each channel of this amplifier is 15 W to a 4 ohm speaker and hence the name 4×15 W power amplifier.
- For obtaining optimum sound quality assemble above circuit on a good quality PCB
- The applications of this circuit have a wide range such as car audio systems, home theater systems, personal audio systems, public address systems etc.