Car Booster Amplifier Adaptor Circuit Diagram

Introduction

Judging by the cacophony emanating from an increasing number of cars on the road, car radio boosters unfortunately remain popular with young people. Unfortunately, due to the fact deafness amongst those younger human beings is turning into pretty common. Get the most out of your car audio system with a car booster amplifier adaptor. Learn more about how to choose the right one for your car and get the best sound quality.

From a technical point of view, the setup with a booster is often very efficient, because these powerful monsters are normally connected simply to the loud-speaker terminals of the existing car radio installation via an attenuator. This puts the two output amplifiers in series, which is, as said, quite inefficient.

Circuit Diagram

of Car Booster Amplifier Adaptor

More Circuit Layouts

Working Explanation

of Car Booster Amplifier Adaptor

It is much better to take the signal from the wiper of the volume control in the car radio and use this as the input to the booster. This is typically now no longer plenty of a job. The signal so obtained must, however, be buffered and sometimes also amplified.

The adaptor provides both these functions in a simple manner. The stereo signals are applied via K1‚and K2‚‚ and buffered and amplified by an op-amp in each channel. The amplification may be set between x1.5 and x22 with P1‚ and P2 respectively. These levels should be more than adequate for most situations. The peak output voltage is 2 VRMS.

The output in each channel is split into a front and a rear branch (left-hand front, LF, and left-hand back, LB, and RF and RB respectively). The volume of the rear audio system is about P3.

A stable 9V supply line is also provided by regulator IC1, for the op-amps. The circuit doesn’t draw a current of more than 7 mA.

The adaptor is best built on the printed circuit shown, which is, however, not commercially available, but may be made with the aid of the relevant track layout.

There are two input and output terminals are given as audio sockets for board mounting.

The battery voltage is applied to the circuit via two car-type connectors mounted on the board. When the adaptor is fitted in a small case, care must be taken so that P3 remains accessible.

Components List

of Car Booster Amplifier Adaptor

• Resistors:
• R1‚, R2‚‚, R6, R7 = 1 M
• R3, R8= 470 ohms
• R4, R9 = 10 k
• R5, R10 = 100 ohms
• P1, P2 = 25 k preset
• P3 = 10 k log stereo pot
  
  Capacitors:
• C1 = 100 uF, 35 V, radial
• C2 = 0.001 uF, high stability
• C3, C6, C7 = 10 uF, 16 V, radial
• C4, C5 = 0.022 uF
• C8, C9 = 47 uF, 16 V, radial
  
  Inductors:
• L1 = 100 uH
• Integrated circuits:
• IC1 = 7809
• IC2, IC3 = TL071CP
  
  Miscellaneous:
• K1-K6 = audio socket for board mounting
• 2 off car-type connectors for board mounting