60W Bass Amplifier

Low-cut and Bass controls

Output power: 40W into 8 Ohm and 60W into 4 Ohm loads

Amplifier circuit diagram:

Amplifier parts:

R1__________________6K8    1W Resistor

R2,R4_____________470R   1/4W Resistors

R3__________________2K   1/2W Trimmer Cermet

R5,R6_______________4K7  1/2W Resistors

R7________________220R   1/2W Resistor

R8__________________2K2  1/2W Resistor

R9_________________50K   1/2W Trimmer Cermet

R10________________68K   1/4W Resistor

R11,R12______________R47   4W Wirewound Resistors

C1,C2,C4,C5________47µF   63V Electrolytic Capacitors

C3________________100µF   25V Electrolytic Capacitor

C6_________________33pF   63V Ceramic Capacitor

C7_______________1000µF   50V Electrolytic Capacitor

C8_______________2200µF   63V Electrolytic Capacitor (See Notes)

D1_________________LED    Any type and color

D2________Diode bridge   200V 6A

Q1,Q2____________BD139    80V 1.5A NPN Transistors

Q3_____________MJ11016   120V 30A NPN Darlington Transistor (See Notes)

Q4_____________MJ11015   120V 30A PNP Darlington Transistor (See Notes)

SW1_______________SPST Mains switch

F1__________________4A Fuse with socket

T1________________220V Primary, 48-50V Secondary 75 to 150VA

                  Mains transformer (See Notes)

PL1_______________Male Mains plug

SPKR______________One or more speakers wired in series or in parallel

                  Total resulting impedance: 8 or 4 Ohm

                  Minimum power handling: 75W

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Preamplifier circuit diagram:

Preamplifier parts:

P1_________________10K   Linear Potentiometer

P2_________________10K   Log. Potentiometer

R1,R2______________68K   1/4W Resistors

R3________________680K   1/4W Resistor

R4________________220K   1/4W Resistor

R5_________________33K   1/4W Resistor

R6__________________2K2  1/4W Resistor

R7__________________5K6  1/4W Resistor

R8,R18____________330R   1/4W Resistors

R9_________________47K   1/4W Resistor

R10________________18K   1/4W Resistor

R11_________________4K7  1/4W Resistor

R12_________________1K   1/4W Resistor

R13_________________1K5  1/4W Resistor

R14,R15,R16_______100K   1/4W Resistors

R17________________10K   1/4W Resistor

C1,C4,C8,C9,C10____10µF   63V Electrolytic Capacitors

C2_________________47µF   63V Electrolytic Capacitor

C3_________________47pF   63V Ceramic Capacitor

C5________________220nF   63V Polyester Capacitor

C6________________470nF   63V Polyester Capacitor

C7________________100nF   63V Polyester Capacitor

C11_______________220µF   63V Electrolytic Capacitor

Q1,Q3____________BC546    65V 100mA NPN Transistors

Q2_______________BC556    65V 100mA PNP Transistor

J1,J2___________6.3mm. Mono Jack sockets

SW1_______________SPST Switch