This is a simple power amplifier with bass treble tone control circuit which you can build by yourself. It uses common – cheap components which are not hard or difficult to obtain.
Briefly about the Circuit
The circuit has three (3) stages; Preamplifier stage, Bass Treble Control stage, and the output power amplifier driver stage.
The preamplifier stage which is base on the Op Amp chip LM741 amplifies the input audio signal which is applied to the system. Hence, this signal is powerful compared to the input signal when it reaches to the tone control stage. Meanwhile you can use any of the 741 Chips apart from the one used in this project, that is “LM” product.
Bass Treble Control Stage
Here, the bass treble tone control stage is used to tone between low (bass) frequencies and treble (MID and HIGH) audio frequencies.
In this design, VR1 is a potentiometer which you can use to vary the input signal. Therefore, VR1 is the volume controller component. VR2 controls the low (bass) audio frequencies by moving it up or down. When you move the VR2 up it allows more low frequencies pass by cutting the high frequencies from the input and also, moving it down cuts the low (bass) frequencies thereby allowing more treble to the output. VR3 and VR4 control the MID frequencies and High frequencies respectively by moving the potentiometer up or down.
Output Power Driver Stage
This stage which is the final stage amplifies the low power input signal to a very powerful level. The heart of this stage is the TDA7377 amplifier circuit.This circuit can output only a maximum 60W of power. TDA7377 is a quadruplet (4 inputs and 4 outputs channels) audio amplifier chip where each channel can deliver 15W output power. However, this design bridges the chip so that you achieve two channels where you can expect only 30W maximum at each bridged channel. Make sure you mount the IC on a sufficient heatsink to minimize heat while the amplifier operates. Also, you can incorporate any means of heat cooling system to the circuit.
Parts of the Amplifier with Bass Treble Control
These are the values of the components which are on the circuit
C1, C10, and C11 = 1µF (Electrolytic Polarized Capacitors)
C2 and C3 = 10µF (Electrolytic)
C4 and C7 = 33nF
C5 = 330nF
C6 and C9 = 3.3nF
C8 = 0.33nF
C12 = 10µF (Electrolytic)
C13 = 47µF
C14 = 1000µF (Electrolytic)
C15 = 100nF
VR1 = 50KΩ
VR1, VR2, VR3, and VR4 = 100KΩ
R1 = 1KΩ
R2 and R3 = 22KΩ
R4 = 220KΩ
R5 and R7 = 10KΩ
R6 = 1.5KΩ
R8 and R9 = 330Ω
R10 and R11 = 100Ω