This is a high quality 65W power amplifier circuit based HEXFET IRF9540 and IRF540. The circuit is quite simple for amplifier with good sound quality. The component parts is easy to find at electronic store around your place. It uses split power supply. Q8, Q10, Q11, Q12, Q13 should be mounted on heatsink for thermic stability.
Parts list:
| R1-15-16-21-22-17-18 = 1Kohm | R33 = 68ohm 5W | Q1-2 = BC550C |
| R2 = 47Kohm | R35-36 = 6.8ohm 1W | Q3-4 = BC560C |
| R3-4 = 10Mohm | TR1 = 1Kohm trimmer | Q5 = BC560C |
| R5-6-13-14 = 1.2Kohm | TR2 = 1Mohm trimmer | Q6 = BC550C |
| R7-12 = 47ohm | C1 = 2.2uF 63-100V MKT | Q7-11 = BD140 |
| R8-9-10-11 = 22ohm | C2 = 1nF 100V MKT | Q8-9-10 = BD139 |
| R19 = 82ohm | C3-4 = 2.7nF 100V MKT | Q12 = IRF9540 |
| R20 = 22Kohm | C5 = 330pF ceramic or mylar | Q13 = IRF540 |
| R23-26 = 56ohm | C6-7 = 100uF 16V | F1-2 = Fuse 2.5A Fast |
| R24 = 2.2Kohm | C8 = 1uF 100V MKT | L1 = see text [2] |
| R25 = 560ohm | C9-11-12 = 100nF 100V MKT | J1 = 2pin connector 2.54mm step |
| R27-30 = 150ohm | C10-13 = 470uF 63V | |
| R28-29-31-34 = 15ohm | C14 = 33nF 100V MKT | Q8-10-11-12-13 on Heatsink |
| R32 = 150ohm 5W | D1-2 = LED RED 3mm [see text] [1] | All the resistors is 1/4W 1% except quote differently |
Here the PCB design layout for this 65W power amplifier:
Power supply for 65W power amplifier circuit using HEXFET:
Power Supply output voltages:
+V1=+35V -V1=-35V
+V2=+12V -V2=-12V
+V3=+35V -V3=-35V
Power supply parts list:
| T1 = 2 x 25VAC ; 3A ; 160VA // 2X15VAC ; 1A ; 20VA T2 = 2 x 25VAC ; 3A ; 160VA BR1-3 = 200V 35A Bridge Rectifier BR2 = 4 X 1N4002 IC1 = 7812 Regulator C5-8 = 1000uF/25V C6-9 = 100nF |
C7-10 = 10uF/25V C15 = 33nF/630V Class X2 C1,C2,C3,C4,C11,C12,C13,C14 = 10000uF/63V IC2 = 7912 Regulator F1 = FUSE 2A slow block S1 = 2X2 switch 10A JF1 = 3 pole male plug |
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