PB-1838GX PB-738GX
USER'S MANUAL
PB-238GX
PB-1038GX
www.pyramidcaraudio.com
PB-638GX
congratulations...
on your purchase of a Pyramid Royal Blue Series
amplifier. This amplifier extends the Pyramid
tradition into a totally new series of amps, designed
from the ground up to deliver the power,
performance and flexibility the modern car audio
enthusiast demands.
When you check the list of features offered by the
PB-238GX, PB-638GX, PB-738GX, PB-1038GX, PB-
1838GX, you’ll know you made the right choice
with a Pyramid Power amplifier.
table of contents
general features
features and specifications
PB-238GX
PB-738GX
PB-1838GX
PB-638GX/PB-1038GX
electrical connections
PB-238GX
PB-638GX/PB-738GX
PB-1038GX/PB-1838GX
stereo input connections
PB-738GX/PB-1838GX
mono input connections
PB-738GX/PB-1838GX
2/4 channel input connections
PB-238GX
2-3
4-5
6-7
8-9
10-11
12
13
14-15
high level input connections
PB-638GX/PB-1038GX
mono input connections
PB-638GX/PB-1038GX
high level mono input connections
PB-638GX/PB-1038GX
speaker connections
PB-738GX/PB-1838GX
speaker connections
PB-238GX/PB-638GX/PB-1038GX
mounting and installation
protection circuitry and troubleshooting
precautions
16-17
18
19
1
20
21-22
23
24
25
general features
PB
High Performance 400 Watt 4 Channel Amplifier
· 100 Watts x 4 Output
· Variable Input Level (Gain) Control
· Remote Turn On/Off
· Gold Plated RCA Inputs
· High Level MOLEX Inputs
· Power ON LED Indicator
· S/N Ratio: > 95 dB
· THD: <0.04%
· Overload Protection
· Short Circuit Protection
· Anti-Thump Turn-On
-238G
X
PB
High Performance 1600 Watt 4 Channel
Bridgeable MOSFET Amplifier
· 400 Watts x 4 Output
· 800W x 2 Bridged Output (400W x 2 + 800W x 1)
· Dual Variable Hi/Lo Electronic Crossover Network
· Dual Variable Bass Boost (0 - +18 dB @ 60Hz)
· Variable Input Level (Gain) Control
· Remote Turn On/Off
· Gold Plated RCA Inputs
· High Level MOLEX Inputs
· Power ON LED Indicator
· LED Protection Indicator
· Remote Bass Boost
· S/N Ratio: > 95 dB
· THD: <0.04%
· Thermal Protection
· Overload Protection
· Short Circuit Protection
· Anti-Thump Turn-On
· Tri-Mode Configurable
-638G
X
PB
High Performance 1000 Watt 2 Channel
Bridgeable MOSFET Amplifier
· 500 Watts x 2 Output
· 1000W x 1 Bridged Output
· Variable Hi/Lo Electronic Crossover Network
· Variable Bass Boost (0 - +18 dB @ 60Hz)
· Variable Input Level (Gain) Control
· Remote Turn On/Off
· Gold Plated RCA Inputs
· High Level MOLEX Inputs
· Power ON LED Indicator
· LED Protection Indicator
· Remote Bass Boost
· S/N Ratio: > 95 dB
· THD: <0.04%
· Thermal Protection
· Overload Protection
· Short Circuit Protection
· Anti-Thump Turn-On
-738G
X
2
general features
PB
High Performance 40
Bridgeable MOSFET Amplifier
· 1000 Watts x 4 Output
· 2000 Watts x 2 Bridged Output(1000Wx2+2000Wx1)
· Dual Variable Hi/Lo Electronic Crossover Network
· Dual Variable Bass Boost (0 - +18 dB @ 60Hz)
· Variable Input Level (Gain) Control
· Remote Turn On/Off
· Gold Plated RCA Inputs
· High Level MOLEX Inputs
· Power ON LED Indicator
· LED Protection Indicator
· Remote Bass Boost
· S/N Ratio: > 95 dB
· THD: <0.04%
· Thermal Protection
· Overload Protection
· Short Circuit Protection
· Anti-Thump Turn-On
· Tri-Mode Configurable
-
1038G
00 Watt 4 Channel
X
PB-1836GX
High Performance 3000 Watt 2 Channel
Bridgeable MOSFET Amplifier
· 1500 Watts x 2 Output
· 3000W x 1 Bridged Output
· Variable Hi/Lo Electronic Crossover Network
· Variable Bass Boost (0 - +18 dB @ 60Hz)
· Variable Input Level (Gain) Control
· Remote Turn On/Off
· Gold Plated RCA Inputs
· High Level MOLEX Inputs
· Power ON LED Indicator
· LED Protection Indicator
· Remote Bass Boost
· S/N Ratio: > 95 dB
· THD: <0.04%
· Thermal Protection
· Overload Protection
· Short Circuit Protection
· Anti-Thump Turn-On
3
features and controls
4 ch amp PB-238GX
high level inputs
low level inputs
input level control
speaker connections
HI IN
CH4 CH3
4 CHANNEL POWER AMPLIFIER
LOW IN
CH 4
+ - - +
CH 3
LEVEL
POWER
MIN MAX
MIN MAX
LEVEL
LOW IN
CH 1
CH 2
HI IN
CH2 CH1
+ - - +
power LED
4
high level inputs
low level inputs
input level control
GROUND
REM
+12V BATT
power terminals
power fuse
CH1
CH2
+
+
-
CH3
CH4
+
+
-
--
FUSE
features and specifications
4 ch amp PB-238GX
input level control
low level inputs
high level inputs
power LED
power fuse
power terminals
speaker connections
use this control to match the outputs of your head unit to the amplifier.
Starting with your head unit set at about the 2 o’clock position, increase
the amp level control until distortion begins to occur, and reduce slightly
from this point.
this amp features gold-plated RCA input jacks for high impedance input.
Use these with car stereo output which uses RCA-type connector cables.
if your car stereo lacks RCA-type output jacks, you may connect speaker
output leads to these input connectors.
this indicator is illuminated when power is applied.
the fuse protects the amplifier and your car’s electrical system from short
circuit conditions.
use these connectors to deliver power, ground and remote turn-on control
to the amplifier.
these terminals are 14K gold plated to guarantee high conductivity and
minimum signal loss.
output power @ 14.4v DC, 1KHz
RMS Power @ 4 Ohms
Maximum Power Output
frequency response
input impedance
low level inputs
high level inputs
input sensitivity
low level inputs
high level inputs
power supply voltage
matching speaker impedance
stereo mode
bridged mode
maximum current draw
dimensions (W x H x L)
mm
inches
30 Watts x 4
100 Watts x 4
15 Hz-30 KHz
10K Ohms
100 Ohms
250mV
2.5V
14.4V DC Neg. Ground (10.5-16V)
2-4 Ohms
4-8 Ohms
10A
274 x 61 x 235
10.8 x 2.4 x 9.25
5
features and controls
2 ch amp PB-738GX • PB-1238GX
power LED
protection LED
Remote Bass Boost
high pass frequency control
low pass frequency control
bass boost level
crossover mode selector
speaker connections
REMOTE
BASS BOOST
2 CHANNEL MOSFET AMPLIFIER
POWERPROTECT
L
+
+
-
BRIDGED
+
HPF
80 2.5k
Hz
R
LOW IN
L
HI IN
R L
+ - - +
R
high level inputs
6
BASS
LPF
BOOST
35
400
0
+18db
Hz
LEVEL
FREQ.
HPF
MIN MAX
LPF
FULL
low level inputs
input level control
GROUND
REM
+12V BATT
-
FUSE
power terminals
-
power fuse
crossover mode selectors
input level controls
low pass frequency controls
high pass frequency controls
Remote Bass Boost Plug in the Remote Bass Boost Control wire in here.
bass boost level controls
low level inputs
high level inputs
power LED
protection LED
power fuse
power terminals
speaker connections
features and specifications
when used with normal, full range systems, set these switches to “FULL.”
If you wish to use the internal crossovers to power a driver of specific
frequency range, use the “LOWPASS” or “HIGHPASS” settings.
use these controls to match the outputs of your head unit to the amplifier.
Starting with your head unit set at about the 2 o’clock position, increase
the amp level controls until distortion begins to occur, and reduce slightly
from this point.
when one or both of the crossover selector switches is in “low pass”
mode, one can set the upper frequency limit for audio program sent to
the speakers.
when the one or both of crossover selector switch is in “high pass” mode,
one can set the lower frequency limit for audio program sent to the
speakers.
this control permits adjustment of the bass level up to an increase of
approximately 18 dB in either or both pairs of channels.
this amp features gold-plated RCA input jacks for high impedance input.
Use these with car stereo output which uses RCA-type connector cables.
if your car stereo lacks RCA-type output jacks, you may connect speaker
output leads to these input connectors.
this indicator is illuminated when power is applied.
this indicator is illuminated when built-in protection circuitry is activated.
the fuse protects the amplifier and your car’s electrical system from short
circuit conditions.
use these connectors to deliver power, ground and remote turn-on control
to the amplifier.
these terminals are 14K gold plated to guarantee high conductivity and
minimum signal loss.
2 ch amp PB-738GX • PB-1838GX
250mV
2.5V
PB
-1838GX
150 Watts x 2
250 Watts x 2
1500 Watts x 2
274 x 61 x 432
10.8 x 2.4 x 12
7
output power @ 14.4v DC, 1KHz
RMS Power @ 4 Ohms
RMS Power @ 2 Ohms
Maximum Power Output
frequency response
input impedance
low level inputs
high level inputs
input sensitivity
low level inputs
high level inputs
power supply voltage
matching speaker impedance
stereo mode
bridged mode
maximum current draw
dimensions (W x H x L)
mm
inches
PB
-738GX
75 Watts x 2
125 Watts x 2
500 Watts x 2
15 Hz-30 KHz
10K Ohms
100 Ohms
14.4V DC Neg. Ground (10.5-16V)
2-4 Ohms
4-8 Ohms
20 A 40 A
274 x 61x 305
10.8 x 2.4 x 12
features and controls
4 ch amp PB-638GX • PB-1038GX
ch 3/4 input level control
ch 3/4 high level inputs
ch 3/4 low level inputs
ch 3/4 crossover mode selector switch
ch 3/4 bass boost level control
ch 3/4 low pass frequency control
ch 3/4 high pass frequency control
protection LED
power LED
speaker connections
+ - - +
CH4 CH3
HI IN
LOW IN
LEVEL
CH 4
MIN MAX
CH 3
CH1
+
-
BASS
BOOST
HPF
LPF
FREQ.
HPF
LPF
35
80
400
0
+18db
FULL
CH2
+
-
2.5k
Hz
Hz
REMOTE
BASS BOOST(CH3/4)
4 CHANNEL MOSFET AMPLIFIER
CH3
CH4
+
+
BASS
BOOST
LPF
HPF
35
80
400
2.5k
0
Hz
Hz
CHANNEL 1/2CHANNEL 3/4
POWERPROTECT
--
FUSE
LEVEL
FREQ.
HPF
LPF
+18db
FULL
GROUND
MIN MAX
CH 2
+ - - +
CH2 CH1
HI IN
CH 1
LOW IN
REM
+12V BATT
ch 1/2 input level control
ch 1/2 high level inputs
ch 1/2 low level inputs
ch 1/2 crossover mode selector switch
ch 1/2 bass boost level control
ch 1/2 low pass frequency control
ch 1/2 high pass frequency control
8
power terminals
BRIDGED
+
BRIDGED
+
-
-
power fuse
features and specifications
dual crossover mode selectors
dual input level controls
dual low pass frequency controls
dual high pass frequency controls
CH 3/4 Remote Bass Boost Plug in the Remote Bass Boost Control wire in here.
dual bass boost level controls
low level inputs
high level inputs
power LED
protection LED
power fuse
power terminals
speaker connections
when used with normal, full range systems, set these switches to “FULL.”
If you wish to use the internal crossovers to power a driver of specific
frequency range, use the “LOWPASS” or “HIGHPASS” settings.
use these controls to match the outputs of your head unit to the amplifier.
Starting with your head unit set at about the 2 o’clock position, increase
the amp level controls until distortion begins to occur, and reduce slightly
from this point.
when one or both of the crossover selector switches is in “low pass”
mode, one can set the upper frequency limit for audio program sent to
the speakers.
when the one or both of crossover selector switch is in “high pass” mode,
one can set the lower frequency limit for audio program sent to the
speakers.
this control permits adjustment of the bass level up to an increase of
approximately 18 dB in either or both pairs of channels.
this amp features gold-plated RCA input jacks for high impedance input.
Use these with car stereo output which uses RCA-type connector cables.
if your car stereo lacks RCA-type output jacks, you may connect speaker
output leads to these input connectors.
this indicator is illuminated when power is applied.
this indicator is illuminated when built-in protection circuitry is activated.
the fuse protects the amplifier and your car’s electrical system from short
circuit conditions.
use these connectors to deliver power, ground and remote turn-on control
to the amplifier.
these terminals are 14K gold plated to guarantee high conductivity and
minimum signal loss.
4 ch amp PB-638GX • PB-1038GX
250mV
2.5V
PB
-1038GX
75 Watts x 4
125 Watts x 4
1000 Watts x 4
274 x 61 x 432
10.5 x 2.4 x 17
9
output power @ 14.4v DC, 1KHz
RMS Power @ 4 Ohms
RMS Power @ 2 Ohms
Maximum Power Output
frequency response
input impedance
low level inputs
high level inputs
input sensitivity
low level inputs
high level inputs
power supply voltage
matching speaker impedance
stereo mode
bridged mode
maximum current draw
dimensions (W x H x L)
mm
inches
PB
-638GX
35 Watts x 4
65 Watts x 4
400 Watts x 4
15 Hz-30 KHz
10K Ohms
100 Ohms
14.4V DC Neg. Ground (10.5-16V)
2-4 Ohms
4-8 Ohms
20 A 40 A
274 x 61 x 305
10.5 x 2.4 x 12
electrical connections
2 ch amp PB-738GX • PB-1838GX
+
+
L
-
BRIDGED
GROUND
REM
+12V BATT
R
+
-
FUSE
10
-
12V battery
head unit
to remote turn-on
+12V
electrical connections
4 ch amp PB-238GX • PB-638GX • PB-1038GX
GROUND
REM
+12V BATT
CH1
CH2
+
+
-
BRIDGED
+
CH3
CH4
+
+
-
BRIDGED
+
-
--
-
FUSE
11
12V battery
GROUND
REM
+12V BATT
CH1
CH2
+
+
-
CH3
CH4
+
+
-
--
FUSE
to remote turn-on
BRIDGED
+
BRIDGED
+
-
-
12V battery
head unit
+12V
to remote turn-on
+12V
head unit
using low level inputs
stereo input connections
2 ch amp PB-738GX • PB-1838GX
REMOTE
BASS BOOST
using high level inputs
head unit
L L RR
from speaker terminals
2 CHANNEL MOSFET AMPLIFIER
LPF
HPF
POWERPROTECT
35
400
80 2.5k
Hz
Hz
LOW IN
L
HI IN
R L
+ - - +
R
BASS
BOOST
0
+18db
LEVEL
FREQ.
HPF
MIN MAX
LPF
FULL
head unit
L/R Audio
Outputs
12
Y Adaptors
PLEASE NOTE! If using high level
inputs, do not use the low level RCA
inputs at the same time!
REMOTE
BASS BOOST
2 CHANNEL MOSFET AMPLIFIER
LPF
HPF
POWERPROTECT
35
400
80 2.5k
Hz
Hz
BASS
BOOST
0
+18db
LEVEL
FREQ.
HPF
MIN MAX
LPF
FULL
LOW IN
L
HI IN
R L
+ - - +
R
using low level inputs
mono input connections
2 ch amp PB-738GX • PB-1838GX
To a second amplifier
REMOTE
BASS BOOST
To a second amplifier
using high level inputs
head unit
RRLL
from speaker terminals
2 CHANNEL MOSFET AMPLIFIER
LPF
HPF
POWERPROTECT
35
400
80
2.5k
Hz
Hz
LOW IN
L
HI IN
R L
+ - - +
R
BASS
BOOST
0
+18db
LEVEL
FREQ.
HPF
MIN MAX
LPF
FULL
head unit
13
Y Adaptors
PLEASE NOTE! If using high level
inputs, do not use the low level RCA
inputs at the same time!
REMOTE
BASS BOOST
2 CHANNEL MOSFET AMPLIFIER
LPF
HPF
POWERPROTECT
35
400
80 2.5k
Hz
Hz
BASS
BOOST
0
+18db
LEVEL
FREQ.
HPF
MIN MAX
LPF
FULL
LOW IN
L
HI IN
R L
+ - - +
R
wiring harnesswiring harness
2/4 channel input connections
4 CH input connections using low level inputs
4 ch amp PB-238GX
4 CHANNEL POWER AMPLIFIER
LOW IN
CH 3
HI IN
CH4 CH3
+ - - +
L/R REAR
Audio Outputs
CH 4
LEVEL
MIN MAX
2 CH input connections using low level inputs
4 CHANNEL POWER AMPLIFIER
LOW IN
CH 3
HI IN
CH4 CH3
+ - - +
CH 4
LEVEL
MIN MAX
POWER
POWER
LEVEL
MIN MAX
LEVEL
MIN MAX
LOW IN
CH 1
CH 2
HI IN
CH2 CH1
+ - - +
L/R FRONT
Audio Outputs
head unit
14
LOW IN
CH 1
CH 2
HI IN
CH2 CH1
+ - - +
Y adaptors
L
R
high level
4 CH floating ground connections
input connections
4 ch amp PB-238GX
HI IN
CH4 CH3
ORANGE
BLACK
BLACK
ORANGE
PLEASE NOTE! If using high level inputs,
do not use the low level RCA inputs at
the same time!
4 CHANNEL POWER AMPLIFIER
LOW IN
CH 3
CH 4
+ - - +
L R FRONTL RREAR
from speaker terminals
LEVEL
MIN MAX
POWER
LEVEL
MIN MAX
LOW IN
CH 2
ORANGE
BLACK
BLACK
ORANGE
CH 1
HI IN
CH2 CH1
+ - - +
15
4 CH harness wiring for common ground connections
CH 3/4
L R FRONTRLREAR
ORANGE
BLACK
BLACK
ORANGE
from speaker terminals
CH 1/2
ORANGE
BLACK
BLACK
ORANGE
Stereo
4 ch amp PB-638GX • PB-1038GX
4 CH Stereo input connections using low level inputs
input connections
BASS
BOOST
FREQ.
LPF
HPF
HPF
35
80
400
2.5k
0
+18db
Hz
Hz
CHANNEL 1/2CHANNEL 3/4
POWERPROTECT
+ - - +
CH4 CH3
HI IN
L/R REAR
Audio Outputs
LOW IN
LEVEL
CH 4
MIN MAX
CH 3
BASS
BOOST
HPF
LPF
FREQ.
HPF
LPF
35
80
400
0
FULL
2.5k
+18db
Hz
Hz
REMOTE
BASS BOOST(CH3/4)
4 CHANNEL MOSFET AMPLIFIER
2 CH Stereo input connections using low level inputs
BASS
BOOST
FREQ.
LPF
HPF
HPF
35
80
400
2.5k
0
+18db
Hz
Hz
CHANNEL 1/2CHANNEL 3/4
POWERPROTECT
+ - - +
CH4 CH3
HI IN
LOW IN
LEVEL
CH 4
MIN MAX
CH 3
BASS
BOOST
HPF
LPF
FREQ.
HPF
LPF
35
80
400
0
FULL
2.5k
+18db
Hz
Hz
REMOTE
BASS BOOST(CH3/4)
4 CHANNEL MOSFET AMPLIFIER
LEVEL
CH 2
+ - - +
LOW IN
CH2 CH1
HI IN
CH 1
L/R FRONT
Audio Outputs
head unit
LPF
MIN MAX
FULL
16
LEVEL
CH 2
+ - - +
LOW IN
CH2 CH1
HI IN
CH 1
R
Y adaptors
L
LPF
MIN MAX
FULL
high level
4 CH floating ground connections
Stereo
4 ch amp PB-638GX • PB-1038GX
input connections
CH 4
+ - - +
CH4 CH3
HI IN
CH 3
LOW IN
ORANGE
BLACK
BLACK
ORANGE
PLEASE NOTE! If using high level inputs,
do not use the low level RCA inputs at
the same time!
LEVEL
FREQ.
HPF
LPF
MIN MAX
FULL
L R FRONTL RREAR
from speaker terminals
BOOST
0
BASS
HPF
LPF
35
80
400
+18db
2.5k
Hz
Hz
REMOTE
BASS BOOST(CH3/4)
4 CHANNEL MOSFET AMPLIFIER
BASS
BOOST
LPF
HPF
35
80
400
2.5k
0
Hz
Hz
CHANNEL 1/2CHANNEL 3/4
POWERPROTECT
LEVEL
FREQ.
HPF
+18db
CH 2
+ - - +
LOW IN
CH2 CH1
HI IN
CH 1
LPF
MIN MAX
FULL
17
4 CH harness wiring for common ground connections
CH 1/2
ORANGE
BLACK
BLACK
ORANGE
ORANGE
BLACK
BLACK
ORANGE
CH 3/4
L R FRONTRLREAR
ORANGE
BLACK
BLACK
ORANGE
from speaker terminals
mono
4 ch amp PB-638GX • PB-1038GX
4 CH mono input connections using low level inputs
input connections
BASS
BOOST
LPF
HPF
35
80
400
2.5k
0
+18db
Hz
Hz
CHANNEL 1/2CHANNEL 3/4
POWERPROTECT
+ - - +
CH4 CH3
HI IN
LOW IN
LEVEL
CH 4
MIN MAX
CH 3
BASS
BOOST
HPF
LPF
FREQ.
HPF
LPF
35
80
400
0
FULL
2.5k
+18db
Hz
Hz
REMOTE
BASS BOOST(CH3/4)
4 CHANNEL MOSFET AMPLIFIER
RIGHT FRONT Audio Outputs
RIGHT REAR Audio Outputs
2 CH mono input connections using low level inputs
BASS
BOOST
LPF
HPF
35
80
400
2.5k
0
+18db
Hz
Hz
CHANNEL 1/2CHANNEL 3/4
POWERPROTECT
+ - - +
CH4 CH3
HI IN
LOW IN
LEVEL
CH 4
MIN MAX
CH 3
BASS
BOOST
HPF
LPF
FREQ.
HPF
LPF
35
80
400
0
FULL
2.5k
+18db
Hz
Hz
REMOTE
BASS BOOST(CH3/4)
4 CHANNEL MOSFET AMPLIFIER
LEVEL
FREQ.
HPF
LPF
CH 2
+ - - +
LOW IN
CH2 CH1
HI IN
CH 1
MIN MAX
FULL
head unit
LEFT FRONT Audio Outputs
LEFT REAR Audio Outputs
LEVEL
FREQ.
HPF
LPF
CH 2
+ - - +
LOW IN
CH2 CH1
HI IN
CH 1
MIN MAX
FULL
18
L
Y adaptors
R
high level mono
4 ch amp PB-638GX • PB-1038GX
4 CH Common ground connections
input connections
LEVEL
CH 4
+ - - +
CH4 CH3
HI IN
LOW IN
MIN MAX
CH 3
ORANGE
BLACK
BLACK
ORANGE
PLEASE NOTE! If using high level inputs,
do not use the low level RCA inputs at
the same time!
BASS
BOOST
LPF
FREQ.
HPF
LPF
35
400
0
+18db
FULL
Hz
R L
from speaker terminals
HPF
80
2.5k
Hz
REMOTE
BASS BOOST(CH3/4)
4 CHANNEL MOSFET AMPLIFIER
BASS
BOOST
LPF
HPF
35
80
400
2.5k
0
Hz
Hz
CHANNEL 1/2CHANNEL 3/4
POWERPROTECT
LEVEL
FREQ.
HPF
LPF
+18db
CH 2
+ - - +
MIN MAX
FULL
CH2 CH1
HI IN
CH 1
4 CH harness wiring
LOW IN
for common ground connections
CH 3/4
19
CH 1/2
ORANGE
BLACK
BLACK
ORANGE
ORANGE
BLACK
BLACK
ORANGE
R L
ORANGE
BLACK
BLACK
ORANGE
from speaker terminals
Stereo Output Mode
speaker connections
2 ch amp • PB-738GX • PB-1838GX
+
+
L
-
BRIDGED
GROUND
REM
+12V BATT
R
+
-
-
FUSE
20
RIGHT speakerLEFT speaker
+
+
L
-
BRIDGED
R
+
-
-
FUSE
MINIMUM
SPEAKER
IMPEDANCE
4 OHMS!
speaker
GROUND
REM
+12V BATT
4 ch amp PB-238GX • PB-638GX • PB-1038GX
4 CH Output Mode
speaker connections
CH1
CH2
+
+
-
BRIDGED
+
CH3
CH4
+
+
-
BRIDGED
+
-
--
-
L R
FRONT speakers
R L
REAR speakers
Bridged Dual Mono Output Mode (PB-238GX WITHOUT)
CH1
CH2
+
+
-
BRIDGED
+
speakers
L R
CH3
CH4
+
+
-
BRIDGED
+
-
--
-
FUSE
FUSE
GROUND
GROUND
REM
+12V BATT
21
REM
+12V BATT
MINIMUM
SPEAKER
IMPEDANCE
4 OHMS!
speaker connections
4 ch amp PB-638GX • PB-1038GX
2 CH Bridged Output Mode with Subwoofer Output
CH1
+
BRIDGED
+
SUBWOOFER
GROUND
REM
+12V BATT
22
CH3
BRIDGED
CH4
+
--
-
CH2
+
-
+
-
+
-
FUSE
MINIMUM
SPEAKER
R
L
SPEAKERS
IMPEDANCE
4 OHMS!
mounting and installation
mounting
wiring tips
fuses
Your new Pyramid Royal Blue Series amplifier comes complete with all required mounting hardware. When determining a suitable location in your vehicle for the amp, please
remember that it is a high-power electronic device capable of generating high heat.
For this reason, always choose a location in your vehicle which has low vibration, adequate ventilation, a minimum of dust, and no moisture. Be sure to
mount the amp in such a manner as to allow reasonable airflow over the cooling fins.
Mark the location for the mounting screw holes by positioning the amp where you wish to install it and use a scribe (or one of the mounting screws) inserted in each
of the mounting holes to mark the mounting surface. If the mounting surface is carpeted, measure the hole centers and mark with a felt tip pen.
Before attempting to drill the mounting holes, take note of any wires, lines or other devices in your vehicle which may be located behind the mounting
surface! Then drill pilot holes in the mounting surface for the mounting screws and insert them. Tighten the screws securely.
When making electrical connections to your amplifier, please observe the
following:
Use at least 8 gauge wire for power and ground connections.
Wire the amplifier directly to the car battery.
For the ground connection, use the shortest possible wire to a good chassis ground point.
Wire the Remote connection to the auto start lead of your head unit, equalizer or power antenna.
About power fuses:
Pyramid Royal Blue Series amplifiers feature built-in fuse systems. These fuses protect both
the amplifier and the electrical system in your vehicle from fault conditions. If you ever need
to replace the fuse in your Pyramid Royal Blue Series amp, use a fuse of exactly the same type
and rating. A different type or rating of fuse may result in damage or fire.
23
protection
circuitry
The built-in protection circuitry in the Pyramid
Royal Blue Series amplifiers will disable the amplifier
if it senses an input overload, a speaker short circuit,
or extreme temperature conditions.
troubleshooting
No output.
Confirm that all terminal strip connections are secure and tight.
Check both in-line and built-in fuses. Both the +12V and the Remote terminals must have +12v referenced to chassis
ground.
When the protection circuit is activated by any of
these conditions, the Protection LED will be
illuminated.
If this occurs, carefully inspect the system to
determine the source of the problem.
• If the shutdown was a result of a thermal overload
condition, allow the amplifier to cool down before
attempting to restart it.
• If the shutdown was a result of an input overload,
or speaker short circuit, be sure to correct the
condition before restarting.
The amplifier can be restarted by turning the remote
power OFF and then ON again.
Confirm that the audio signal source (car radio, equalizer, etc.) is connected and is supplying output signal. To
check if the amp is supplying signal, unplug the cables from the signal source (but leave them plugged into the
amp). Briefly tap the center pin of each of the disconnected RCA plugs with your finger. This should produce a noise
(feedback) in your speakers.
Only one channel works.
Confirm that all terminal strip connections are secure and tight.
Check the Balance control on the head unit (or other source) to verify that it is set to its midpoint.
If you are using the Low Level RCA input, reverse the input plugs at the amplifier (i.e., switch the L with the R). If
the channels which is silent switches to the other side, the problem is either in the head unit/other source or the
connecting cables.
Weak output.
Readjust the Input Level Control(s) to better suit the input signal.
Noise in the audio.
If the noise is a “whine” whose pitch follows the engine speed, confirm that the amplifier and any other signal
sources (head unit, etc.) are properly grounded.
If the noise is a “clicking” or “popping” noise whose rate follows the engine speed, this usually means that the
vehicle is equipped with resistor spark plugs and wires, or that the ignition is in need of service.
Check the rounting of the speaker and input wires to make sure they are not adjacent to wires which interconnect
lights and other accessories.
If the above steps fail to improve or clear noise interference, the system should be checked by a professional mobile
audio installer.
24
precautions notes
Do not operate the amplifier when it is unmounted.
Attach all audio system components securely within
the automobile to prevent damage, especially in an
accident.
Do not mount this amplifier so that the wire
connections are unprotected, or in a pinched
condition, or likely to be damaged by nearby objects.
Before making or breaking power connections in
your system, disconnect the vehicle battery. Confirm
that your head unit or other equipment is turned off
while connecting the input jacks and speaker
terminals.
If you need to replace the power fuse, do so only
with a fuse identical to that supplied with the amplifier.
Using a fuse of a different type or rating may result
in damage that isn’t covered in the manufacturer’s
warranty.
STOP
4 ohm
2 -c hannel Amplifier
(Operating in Stereo)
YES! NO!
Two 4-ohm speakers, wired in stereo,
will present a 4-ohm load to each
channel of the amplifier. Most twochannel amplifiers will work well in this
configuration.
sound around, Inc.
1600 63rd street. brooklyn. ny 11204
4 ohm
STOP
4 ohm
4 -c hannel Amplifier
(Operating in Stereo)
YES!
Four 4-ohm speakers, wired in stereo,
will present a 4-ohm load to each
channel of the amplifier. Most fourchannel amplifiers will work well in this
configuration.
sound around, Inc.
1600 63rd street. brooklyn. ny 11204
4 ohm
4 ohm
4 ohm
4 ohm
2 -c hannel Amplifier
(Operating in
Bridged Mono)
4 ohm
Two 4-ohm speakers, wired in parallel
to a bridged two-channel amplifier.
will present a 2-ohm mono load to the
amplifier. MOST TWO-CHANNEL
AMPLIFIERS DO NOT SUPPORT 2-OHM
MONO OPERATION! AMPLIFIER DAMAGE
COULD RESULT!
4 ohm
4 -c hannel Amplifier
(Operating in
Bridged Mono)
4 ohm
4 ohm
4 ohm
NO!
Four 4-ohm speakers, wired in parallel
to a bridged four-channel amplifier,
will present a 4-ohm mono load to the
amplifier. MOST FOUR-CHANNEL
AMPLIFIERS DO NOT SUPPORT 2-OHM
MONO OPERATION! AMPLIFIER DAMAGE
COULD RESULT!
25
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