God City Instruments – Murdock V1.1 Build guide
2
Part
Value
Description
substitute
substitution notes
C1
47n
film cap
10n-100n
input cap
C2
270p
ceramic cap
100p-1n
LPF for entire circuit. Higher values will be darker but less prone to oscillation
C3
1u
film cap
C4
1.5u
film cap
C5
0.15u
film cap
C6
6.8n
film cap
C7
68n
film cap
C8
0.1u
ceramic cap
C9
4.7n
film cap
C10
0.1u
film cap
C11
470p
ceramic cap
100p-1n
LPF for EQ. Higher values will be darker but less prone to oscillation
C12
100u
electrolytic cap
47u
C13
100u
electrolytic cap
47u
D1
1N5818
schottky diode
1n4001, bat41, etc
any protection diode suitable for 9v supply
LED
3mm LED
status LED
IC1
TL072P
OP AMP
TLE2072
more expensive, more headroom
IC2
TLE2074
OP AMP
TL074, TLC2272
less expensive, less headroom
CLR
4.7k
1/4 watt resistor
2k-10k
current limiting resistor for LED
R1
1M
1/4 watt resistor
2.2M
pull down resistor
R2
10k
1/4 watt resistor
bigger
if more headroom is required
R3
1M
1/4 watt resistor
smaller
if more headroom is required
R4
33k
1/4 watt resistor
bigger
if more output is required
R5
10k
1/4 watt resistor
bigger
for less headroom
R6
4.7k
1/4 watt resistor
bigger
for more headroom
R7
330R
1/4 watt resistor
R8
330R
1/4 watt resistor
270R
when also substituting R10 for 120k, produces a wider low mid cut
R9
82k
1/4 watt resistor
100K
for Digitech DPS1550 style. Lowers center frequency of mid band
R10
100k
1/4 watt resistor
120k
when also substituting R18 for 270R, produces a wider low mid cut
R11
10k
1/4 watt resistor
R12
100k
1/4 watt resistor
R13
10K
1/4 watt resistor
R14
10k
1/4 watt resistor
R15
330R
1/4 watt resistor
R16
100k
1/4 watt resistor
R17
10k
1/4 watt resistor
EQ
A5K
16mm pot
S
pad
send to PCB
L+
pad
LED+
L-
pad
LED-
R
pad
return from PCB
V
pad
9v input
G
pad
ground
