18W Audio Amplifier


High Quality very simple unit

No need for a preamplifier


Circuit diagram:

18 Watt Amplifier

Amplifier parts:

P1_____________22K  Log. Potentiometer (Dual-gang for stereo)

R1______________1K  1/4W Resistor
R2______________4K7 1/4W Resistor
R3____________100R  1/4W Resistor
R4______________4K7 1/4W Resistor
R5_____________82K  1/4W Resistor
R6_____________10R  1/2W Resistor
R7_______________R22  4W Resistor (wirewound)
R8______________1K  1/2W Trimmer Cermet (optional)

C1____________470nF  63V Polyester Capacitor
C2,C5_________100µF   3V Tantalum bead Capacitors
C3,C4_________470µF  25V Electrolytic Capacitors
C6____________100nF  63V Polyester Capacitor

D1___________1N4148  75V 150mA Diode

IC1________TLE2141C  Low noise, high voltage, high slew-rate Op-amp

Q1____________BC182  50V 100mA NPN Transistor
Q2____________BC212  50V 100mA PNP Transistor
Q3___________TIP42A  60V 6A    PNP Transistor
Q4___________TIP41A  60V 6A    NPN Transistor

J1______________RCA  audio input socket

Power supply parts:

R9______________2K2 1/4W Resistor

C7,C8________4700µF 25V Electrolytic Capacitors

D2_____________100V 4A Diode bridge
D3_____________5mm. Red LED

T1_____________220V Primary, 15 + 15V Secondary, 50VA Mains transformer

PL1____________Male Mains plug

SW1____________SPST Mains switch

Notes:


Technical data:

Output power:
18 Watt RMS into 8 Ohm (1KHz sine wave)
Sensitivity:
150mV input for 18W output
Frequency response:
30Hz to 20KHz -1dB
Total harmonic distortion @ 1KHz:
0.1W 0.02% 1W 0.01% 5W 0.01% 10W 0.03%
Total harmonic distortion @10KHz:
0.1W 0.04% 1W 0.05% 5W 0.06% 10W 0.15%
Unconditionally stable on capacitive loads