GOD CITY INSTRUMENTS Baracus V1.5 User manual

God$City$Instruments–$Baracus$V1.5$Build$guide$
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GOD$CITY$INSTRUMENTS$–$Baracus$V1.5$Build$guide$
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The$God$City$Instruments$(GCI)$Baracus$is$a$medium>gain$silicon/germanium$hybrid$fuzz$loosely$based$on$an$
NPN$interpretation$of$the$Baldwin$Burns$Buzzaround$circuit.$The$first$two$transistors$have$been$replaced$with$
common$silicon$bipolar$junction$transistors,$however,$Q3,$the$transistor$most$responsible$for$the$
characteristic$Buzzaround$tone$remains$a$germanium.$$$
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Transistor$selection$and$biasing$has$a$huge$influence$on$the$tone$of$this$pedal.$$Depending$on$transistor$choice$
and$bias,$this$circuit$can$produce$anything$from$a$loud$clean$boost,$to$squishy,$zipper,$gated$fuzz,$to$heavy,$
thick$saturation.$$Adjustments$to$resistor$values$may$be$required$for$proper$bias$of$Q1$and$Q2.$$Because$a$
wide$range$of$useable$tones$can$be$found$when$adjusting$the$voltage$feeding$Q3,$it’s$bias$pot$has$been$
configured$as$an$external$control.$$While$not$necessary,$a$VC$bias$pad$and$extra$ground$pad$are$provided$in$
case$external$bias$points$or$a$meter$is$desired.$$$
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This$pedal$is$an$easy$build,$but$this$guide$is$intended$for$people$who$have$some$experience$building$pedals.$$
Component$sourcing,$component$identification,$assembly$techniques,$wiring$stomp$switches,$etc.$is$not$
covered.$$The$GCI$Brutalist$Jr.$assembly$guide$has$helpful$information$for$less$experienced$builders.$$That$guide$
can$be$found$here:$
http://www.kurtballou.com/brutalistjr/$
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For$your$convenience,$complete$parts$kits$including$everything$you$need$except$the$PCB$can$be$purchased$
through$Small$Bear$Electronics.$$Be$wary$that$they$may$need$to$make$substitutions$for$work>alike$components$
which$may$or$may$not$influence$the$tone$of$the$pedal.$$Be$aware$that$transistors$may$have$been$substituted$
for$work>alikes$with$different$pinouts.$
http://smallbear>electronics.mybigcommerce.com/kit>baracus>pcb>not>included/$
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Available$separately$is$the$GCI$3PDT$utility$PCB$for$PCB$pin$3PDT$footswitches.$$This$PCB$makes$footswitch$
wiring$quick$and$easy.$$Not$compatible$with$solder$lug$style$switches.$$$
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Don’t$forget$to$connect$the$ground$pad$of$the$PCB$to$the$ground$lug$of$the$input,$output,$and$DC$power$jacks!$
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Due$to$the$scope$of$this$project,$technical$support$is$not$available.$$However,$consider$joining$the$GCI$DIY$PCB$
Builders$group$on$Facebook$to$get$advice$from$and$share$your$work$with$other$builders.$$We$require$that$all$
group$members$agree$to$the$rules$before$being$accepted$into$the$group.$$$
https://www.facebook.com/groups/2454786551255317/$
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Component$values$for$the$PCB$as$well$as$some$alternate$values$are$listed$below.$$This$is$a$BOM$for$the$PCB$
only.$$Resistors$and$diodes$are$6.3mm$leg$spacing,$film$and$ceramic$capacitors$are$5.08mm$leg$spacing,$and$
electrolytic$capacitors$are$2.54mm$leg$spacing.$$I/O$jacks,$DC$jack,$switch,$enclosure,$and$knobs$are$not$listed.$$
The$schematic$and$a$drill$template$for$a$125B$(1590N1)$sized$enclosure$are$also$attached.$
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God$City$Instruments–$Baracus$V1.5$Build$guide$
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Part
Value
Description
Substite
Substitution Notes
C1
47n
film cap
10n - 0.1u
Input cap
C2
470p
ceramic cap
100p-2.2n
Input LPF
C3
4.7u
electolytic cap
2.2u-47u
Bypass cap for Si transistor stage. Bigger for more gain
C4
1u
film cap
C5
0.1u
1000pF - 0.47uF
C6
1u
film cap
C7
47u
electolytic cap
22u-220u
Power filter cap
D1
1n5817
Schottky diode
1n4001, BAT41, 1n5818, etc
Any suitable polarity protection diode for 9v
D2
1n34a
Germanium diode
1n270, 1n949
LED
L1
3mm LED
R1
1M
1/4 watt resistor
2.2M
Pull down resistor
R2
470k
1/4 watt resistor
R3
100k
1/4 watt resistor
R4
10k
1/4 watt resistor
R5
3.3k
1/4 watt resistor
R6
100R
1/4 watt resistor
0R-1k
Affects gain of Si transistor stage
R7
10k
1/4 watt resistor
R8
10k
1/4 watt resistor
R9
10k
1/4 watt resistor
R10
10k
1/4 watt resistor
CLR
4.7k
1/4 watt resistor
1k-10k
Current limiting resistor for LED
Q1
BC108
NPN Si Transistor
2n3904, 2n2222a, BC550, etc
Any medium to high gain BJT should sound good. Double check pinouts.
Q2
BC108
NPN Si Transistor
2n3904, 2n2222a, BC550, etc
Any medium to high gain BJT should sound good. Double check pinouts.
Q3
2n1306
NPN Ge Transistor
MP38A, AC176, 2n1289, etc
BIAS
B50k
16mm potentiometer
VOL
A100K
16mm potentiometer
FUZ
Z
A100K
16mm potentiometer
S
PAD
Send to PCB
L+
PAD
LED+
L-
PAD
LED-
R
PAD
Return from PCB
V
PAD
9v in
G
PAD
Ground
VC
PAD
Q3 bias point
bias probe
Check bias voltage here. Wire to extermal probes or meters if you're interested.
G1
PAD
Ground
bias probe
Check bias voltage here. Wire to extermal probes or meters if you're interested.
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God$City$Instruments–$Baracus$V1.5$Build$guide$
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0.500
0.313
0.125
0 0.559 1.309 2.059 2.618
0
0.829
1.379
1.929
3.828
4.803
0.500
0.375
0 0.772 1.309 1.847 2.618
0
0.454
0.914
1.398