|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|
Can be directly connected to CD players, tuners and tape recorders.
Don't exceed 23 + 23V supply.
Q3 and Q4 must be mounted on heatsink.
D1 must be in thermal contact with Q1.
Quiescent current (best measured with an Avo-meter in series with Q3 Emitter) is not critical.
Adjust R3 to read a current between 20 to 30 mA with no input signal.
To facilitate current setting add R8 (optional).
A correct grounding is very important to eliminate hum and ground loops. Connect in the same point the ground sides of J1, P1, C2, C3&C4. Connect C6 at the output ground.
Then connect separately the input and output grounds at the power supply ground.
Output power: 18 Watt RMS @ 8 Ohm (1KHz sinewave)
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