This is circuit of 15W BTL stereo channel audio power amplifier based 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.
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.
Skema rangkaian Car Audio Amplifier
15W BTL Stereo
R1 with R2 forms a voltage divider that attenuates the input signal by 24dB. Considering the chip's 50dB gain, that still leaves 26dB overall gain, slightly more than enough to fully saturate the amplifier when the sound card works at maximal output. C1 blocks DC at the preamplifier input. C2 is the ground return of the feedback circuit. These two capacitors need to be in the ratio shown, in order to suppress switching clicks when powering the circuit on and off. The output pins 15 and 16 are connected directly to the speaker, while C7, R6, C8 and R7 provide the proper load phase shifting to avoid high frequency instability.
The power supply is decoupled with a rather small 100uF capacitor. That's enough for higher frequency decoupling, and at lower frequencies anyway the large capacitors in the PC power supply are fine. Pins 10 and 17 supply the power amplifiers, while pin 9 provides power to the pre stages. This power is filtered by C3. The power control pin 4 allows to shut down the amplifier, an option not used here, so it's tied to 12V. Pin 1 is a muting input, also not used, and left open.