+15V
0.1µF
1kΩ
1kΩ
Audio
In
1/2
OPA2227
200Ω
200Ω
To
Headphone
1/2
OPA2227
This application uses two op amps
in parallel for higher output current drive.
0.1µF
–15V
FIGURE 17. Headphone Amplifier.
Bass Tone Control
R2
50kΩ
CW
R1
7.5kΩ
R3
7.5kΩ
3
1
2
R10
100kΩ
Midrange Tone Control
C1
940pF
R5
50kΩ
CW
R4
2.7kΩ
R6
2.7kΩ
3
1
VIN
2
C2
0.0047µF
Treble Tone Control
R8
50kΩ
CW
R7
7.5kΩ
R9
7.5kΩ
R11
100kΩ
3
1
2
C3
680pF
2
6
VOUT
OPA227
3
FIGURE 18. Three-Band ActiveTone Control (bass, midrange and treble).
OPA227, 2227, 4227
OPA228, 2228, 4228
17
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SBOS110A