# 65W Power Amplifier using HEXFET circuit diagram

A D V E R T I S E M E N T

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 ;  20VAT2 = 2 x 25VAC ; 3A ; 160VABR1-3 = 200V 35A Bridge RectifierBR2 = 4 X 1N4002IC1 = 7812 RegulatorC5-8 = 1000uF/25VC6-9 = 100nF C7-10 = 10uF/25VC15 = 33nF/630V Class X2C1,C2,C3,C4,C11,C12,C13,C14 = 10000uF/63VIC2 = 7912 RegulatorF1 = FUSE 2A slow blockS1 = 2X2 switch 10AJF1 = 3 pole male plug