Headphone Amp with 3D Sound
Sound reinforcement for iPod & Co.
Published in issue 371, November 2007
Some audio amplifier designs incorporate ‘loudness compensation’ which boosts the bass and treble frequencies at low volume settings so that the tonal characteristics of the amplifier are perceived as being more linear with respect to the volume setting. The headphone amplifier described here combines a high-spec amplifier IC with a discrete transistor front-end giving additional bass and treble lift together with an audio 3D effect.
Resistors (SMD 1206 case) R1,R21 = 33 R2,R22 = see text R3,R23 = 15k R4, R24 = 560 R5,R25,R43,R44 = 33k R6,R12,R26,R32 = 100k R7,R11,R27,R31 = 1k R8,R28 = 1kΩ5 R9,R29,R41,R42,R45,R46,R47 = 10k R10,R30 = 330k R13,R33 = 2kΩ7 R14,R50,R122,R222 = 0 Capacitors (SMD 1206 case unless otherwise indicated C1,C21 = 22nF C2,C22 = see text C3,C4,C5,C7,C23,C24,C25 = 470nF C6,C26 = 470pF C41,C42,C43 = 4µF7 (SMD 1812) C44,C45 = 1µF C50 = 100µF 16V radial (can-style electrolytic) Semiconductors T1-T4 = BC847 (SOT-23) IC1 = MAX4409EUD+ (14-pin TSSOP; Maxim)Miscellaneous 3.5-mm stereo socket, PCB mount with collet nut PCB, order code 070393-1 from www.thepcbshop.com Enclosure
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Click below to download a PDF copy of this article from Elektor magazine.
Please note. In view of the complexity of international markets, Elektor cannot guarantee the availability of components for this project.
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