50 watt Mosfet amplifier

The first stage of the 50 watt Mosfet amplifier is a differential amplifier based on transistors Q1 and Q2. Capacitor C8 is the DC input decoupling, C1 R1 limits input current and a capacitor bypasses undesirable high frequencies. The second stage is composed of the pilot phase transistors Q3 and Q4. The output stage is a complementary push-pull stage based on MOSFET  IRF9530 and IRF530.

50 watt Mosfet amplifier circuit Output is connected to a speaker using inductor L1. Combination network of C5 and R15 are intended for noise reduction. Capacitors C6 and C7 are power supply filter. R6 is set to adjust the quiescent current.

50 watt Mosfet amplifier Parts list :
R1, R12 : 4.7K
R2 : 47K
R3 : 15 K
R4 : 1.2K
R5 : 47K
R6 : 1K var
R7 : 820 ohm
R8 : 10K
R9 : 680 ohm
R10, R11 : 2.7K
R13 : 560 ohm
R14 : 2.2K
R15 : 10 ohm 2W
C1 : 220pF
C2, C3 : 47uF
C4, C6, C7 : 100uF
C5 : 68nF
D1 : 1N4002
Q1, Q2 : BC556
Q3, Q4 : BC546
Q5 : IRF530
Q6 : IRF9530
K1 : 8 ohm

Note:
Assemble the circuit on a good quality PCB.
Use the + /-35V DC dual power supply to power the circuit.
To make the L1 12turns enamelled copper wire on a diameter of 1 cm
C6 and C7 should be 50V; other electrolytes can be 10 or 15V.
Heat sink is required for the MOSFET. A 8x4x4 inch finned heatsink.