General description:
Can be directly connected to CD players, tuners and tape recorders. Simply add a 10K Log potentiometer (dual gang for stereo) and a switch to cope with the various sources you need. Q6 & Q7 must have a small U-shaped heatsink. Q8 & Q9 must be mounted on heatsink. Adjust R11 to set quiescent current at 100mA (best measured with an Avo-meter in series with Q8 Drain) with no input signal. A correct grounding is very important to eliminate hum and ground loops. Connect in the same point the ground sides of R1, R4, R9, C3 to C8. Connect C11 at output ground. Then connect separately the input and output grounds at power supply ground.
Amplifier circuit diagram:
Part list:
| R1,R4 = 47K 1/4W Resistors R2 = 4K7 1/4W Resistors R3 = 1K5 1/4W Resistors R5 = 390R 1/4W Resistors R6 = 470R 1/4W Resistors R7 = 33K 1/4W Resistors R8 = 150K 1/4W Resistors R9 = 15K 1/4W Resistors R10 = 27R 1/4W Resistors R11 = 500R 1/2W Trimmer Cermet R12,R13,R16 = 10R 1/4W Resistors R14,R15 = 220R 1/4W Resistors R17 = 8R2 2W Resistor R18 = R22 4W Resistor (wirewound) | C1 = 470nF 63V Polyester Capacitor C2 = 330pF 63V Polystyrene Capacitor C3,C5 = 470µF 63V Electrolytic Capacitors C4,C6,C8,C11 = 100nF 63V Polyester Capacitors C7 = 100µF 25V Electrolytic Capacitor C9 = 10pF 63V Polystyrene Capacitor C10 = 1µF 63V Polyester Capacitor | Q1-Q5 = BC560C 45V100mA Low noise High gain PNP Transistors Q6 = BD140 80V 1.5A PNP Transistor Q7 = BD139 80V 1.5A NPN Transistor Q8 = IRF532 100V 12A N-Channel Hexfet Transistor Q9 = IRF9532 100V 10A P-Channel Hexfet Transistor |
Power supply circuit diagram:
Part list:
R1 = 3K3 1/2W ResistorC1 = 10nF 1000V Polyester Capacitor
C2,C3 = 4700µF 50V Electrolytic Capacitors
C4,C5 = 100nF 63V Polyester Capacitors
D1 200V 8A Diode bridge
D2 5mm. Red LED
F1,F2 3.15A Fuses with sockets
T1 220V Primary, 25 + 25V Secondary 120VA Mains transformer
PL1 Male Mains plug
SW1 SPST Mains switch
