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25 Watt MosFet Audio Amplifier

High Quality simple unit
No need for a preamplifier

Circuit diagram:

25 Watt Amplifier

R1,R4_________47K  1/4W Resistors
R2____________4K7  1/4W Resistor
R3____________1K5  1/4W Resistor
R5__________390R   1/4W Resistor
R6__________470R   1/4W Resistor
R7___________33K   1/4W Resistor
R8__________150K   1/4W Resistor
R9___________15K   1/4W Resistor
R10__________27R   1/4W Resistor
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   45V 100mA 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:

Power supply

R1____________3K3  1/2W Resistor

C1___________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


Technical data:

Output power: well in excess of 25Watt RMS @ 8 Ohm (1KHz sinewave)

Sensitivity: 200mV input for 25W output

Frequency response: 30Hz to 20KHz -1dB

Total harmonic distortion @ 1KHz: 0.1W 0.014%  1W 0.006%  10W 0.006%  20W 0.007%  25W 0.01%
Total harmonic distortion @10KHz: 0.1W  0.024% 1W 0.016% 10W 0.02%  20W 0.045%  25W 0.07%

Unconditionally stable on capacitive loads

fahd 2010-09-20 22:34:54
please do you have the description of this amplifier ? how it's works ?

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