Amplifier of Acoustic Frequencies with Preamplifier

Characteristics Input Voltage: 15V Output Power: 4,2Wrms @ 4Ohm Minimal input signal: 94mVp-p with preamplifier, 0,65Vp-p without the preamplifier Parts R1 2,2K R2 330K R3 4,7K - logarithmic potentiometer R4 330K R5 1K R6 1.5Ohm C1, C6 100nF polyester C2 100uF/25V electrolytic C3, C7 1uF/25V electrolytic C4 1000uF/25V electrolytic C5 10uF/25V electrolytic Q1 BC547 U1 TDA2002 LS1 speaker Notes Output power related to speaker impedance LS1 Output Power 2Ω 6,5 Wrms 4Ω 4,2 Wrms 6Ω 3 Wrms 8Ω 2,25 Wrms