The amplifier is designed for independent in a small speaker box. Can support to Walkman, Mini-Disc and CD players, computers, and similar devices with line or headphone output. Of course, in many cases, you will need to create two units for stereo.
The circuit is intentionally designed using old type transistor, it is to get the harmonic distortion and to avoid the difficulty of finding good components. This 2 watt Amplifier (s) can be easily supplied by plug-in wall transformer 12V. Closing SW1 bass boost is provided but, at the same time, volume control must be increased to compensate for the loss of power at higher frequencies.
In use, R9 should be carefully adjusted to provide minimum signal for audible distortion consistent cross-over with minimal quiescent current consumption measurement, a good compromise is to set the quiescent current at about 10-15 mA.
2 Watt amplifier circuit Parts list :
P1 = 10K Log. Potentiometer
R1, R2 = 33K Resistors 1/4W
R3 = 33R Resistor 1/4W
R4 = 15K Resistor 1/4W
R5, R6 = 1K Resistors 1/4W
R7 = 680R Resistor 1/4W
R8 = 120R Resistor 1/2W
R9 = 100R 1/2W Trimmer Cermet
C1, C2 = 10μF/63V electrolytic capacitors
C3 = 100UF Electrolytic Capacitor 25V
C4, C7 = CAP 470UF/25V electrolytic capacitors
C5 = 47pF Ceramic Capacitor 63V
C6 = 220nF/63V Capacitor Polyester
C8 = CAP 1000UF Electrolytic Capacitor 25V
D1 = 1N4148 Diode 75V 150mA
Q1 = BC560C 45V 100mA PNP Transistor low-noise, high-gain
Q2 = BC337 45V 800mA NPN Transistor
Q3 = TIP31A Transistor NPN 60V 4A
Q4 = TIP32A Transistor PNP 60V 4A
SW1 SPST switch
SPKR 05/03 Watt speaker, 8, 4 or 2 ohm impedance
