D1
D2
D3
D4
C11
1000uF/25V
C12
1000uF/25V
C13
1000uF/25V
C14
1000uF/25V
R13
4.7
R14
4.7
A
C
B
GND
C15
100uF/25V
C16
100uF/25V
(+)15V
(-)15V
C17
100nF
C18
100nF
4 x BYV27 / BYW29
1
2
3
4
8
U1A
LM4562
5
6
7
U1B
R2
47k
R3
2k
R4
1k
R5
47
C1
4
7
p
F
C2
100pF
C4
4.7uF
(+)15V
(-)15V
C3
100uF
GND
R6
100k
GND
GND
GND
in_A
out_A
R8
47k
R9
2k
R10
1k
R11
47
C5
4
7
p
F
C6
100pF
C8
4.7uF
C7
100uF
GND
R12
100k
GND
GND
GND
in_B
out_B
C9
4.7uF
C10
4.7uF
(+)15V
(-)15V
GND
R1
1k
R7
1k
gnd
GND
gnd
GND
IN
GND
OUT
U2
LM2937ET-15
IN
GND
OUT
U3
LM2990T-15
dual op-amp preamplifier
damian@unisonus.com