How to build Power amplifier 60W/8Ω

August 6, 2010 - category: Audio amplifier


This circuit was designed and manufactured the '80's. From then it works without problem. It does not present any particular constructional problem, beyond known: the attention in the provided force of power supply - choice suitable heatsink and good matching of drivers transistor. Diodes D3…5 should be placed above in heatsink of the power transistors, so that they have thermic coupling with the output transistors. With the trimmer R15, we regulate the continuous voltage, in the exit of amplifier [that works few time and is stabilised thermic ]. With the trimmer TR1, we regulate the bias current of amplifier in the 50 until 100 mΑ. The bias current we can him measure if we measure the fall of voltage in utmost resistances R36 and R37, for the voltage that are given in the circuit the current are roughly 75 mΑ. The voltage that are reported in the drawing are original, but they can they have a tolerance of order ± 10%.

Circuit diagram

Circuit diagram

Parts list

  • R1=1.8Kohm
  • R2=220Kohm
  • R3=27Kohm
  • R4-10-11-17=3.3Kohm
  • R5-9-12-16=100ohm
  • R6=18Kohm
  • R7-13=3.9Kohm
  • R14=10Kohm
  • R15=22Kohm Trimmer
  • R18-23=330ohm
  • R19-21-22=15Kohm
  • R20=12Kohm
  • R24-30=82ohm
  • R25=8.2Kohm
  • R26=27Kohm
  • R27=820ohm
  • R28=3.3Kohm
  • R29=100ohm
  • R31-39=180ohm
  • R32-38=6.8Kohm
  • R33-34=1.2Kohm
  • R35=82ohm /1W
  • R36-37=0.33ohm / 5W
  • R40-41=10ohm / 2W
  • R42=180ohm/5W
  • TR1=4.7Kohm Trimmer
  • D1-2=24V/1W Zener
  • D3....9=1N4002
  • T1-2=BC550C
  • T3-4=BC560C
  • T5-13=BD530
  • T6-8=BC414C
  • Τ9=BC416C
  • T7-10=BD529
  • T11=BD591
  • T14=BD592
  • T12=2N5630
  • T15=2N6030
  • C1=4.7uF/25V
  • C2=470pF
  • C3-4=100uF/63V
  • C5=68pF
  • C6-10=330pF
  • C7=22pF
  • C8=220uF/16V
  • C9=100nF 100V
  • C11-12=10pF
  • C13-15=47uF/63V
  • C16-17=100nF/100V
  • C18-19=100nF/100V

circuit from http://users.otenet.gr/~athsam/power_amplifier_60w.htm

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