Rockford Fosgate 250 sERIES Guide

®®

The “250 Series” Power amplifiers represent the best Rockford Fosgate has to offer! Our
engineers devised technical features which would be considered overkill by other audio
manufacturers, but not at Rockford Fosgate! Trans•nova, DIABLO, and TOPAZ, exclusively
designed by Rockford, are just a few of these features which are described in the Technical
Design Features section of this manual.
The 250x2 is a two-channel amplifier which is optimized to drive 2Ωstereo and 4Ωbridged
loads. The 250m is a single channel amplifier optimized to drive a 2Ω(single amp) or a 4Ω
bridged load (pair of amps bridged to a single load.)
The 250x2 and 250m utilize Rockford's innovative technologies for awesome sound quality,
reliable performance ad tremendous amounts of output power. The “250 Series” represent
exactly what Rockford Fosgate designs: Car Audio for Fanatics!
INTRODUCTION

Dear Customer,
Congratulations on your purchase of the world's finest brand of car audio amplifiers. At Rockford Fosgate we
are fanatics about musical reproduction at its best, and we are pleased you chose our product. Through years
of engineering expertise, hand craftsmanship and critical testing procedures, we have created a wide range of
products that reproduce music with all the clarity and richness you deserve.
For maximum performance we recommend you have your new Rockford Fosgate product installed by an
Authorized Rockford Fosgate Dealer, as we provide specialized training through Rockford Technical Training
Institute(RTTI). Pleasereadyourwarrantyandretainyourreceiptandoriginalcartonforpossiblefutureuse.
Great product and competent installations are only a piece of the puzzle when it comes to your system. Make
sure that your installer is using 100% authentic installation accessories from Connecting Punch in your
installation. Connecting Punch has everything from RCA cables and speaker wire to Power line and battery
connectors. Insist on it! After all, your new system deserves nothing but the best.
To add the finishing touch to your new fanatic image order your Rockford Fosgate wearables, which include
everything from T-shirts and jackets to hats and sunglasses.
TogetafreebrochureonRockfordFosgateproductsandRockfordwearables,pleasecall602-967-3565orFAX
602-967-8132. For International orders, FAX [phone] or call +001-1-602-967-3565.
The serial number can be found on the outside of the box. Please record it in the space provided below as your
permanentrecord. Thiswillserveasverificationofyourfactorywarrantyandmaybecomeusefulinrecovering
your amplifier if it is ever stolen.
Serial Number: __________________________________________
Model Number:__________________________________________
If,after readingyour manual,you stillhave questionsregarding thisproduct, werecommend thatyou seeyour
RockfordFosgatedealer. Ifyouneedfurther assistance,youcan callusdirectat 1-800-795-2385.Besureto have
your serial number, model number and date of purchase available when you call.
PRACTICE SAFE SOUND™
CONTINUOUS EXPOSURE TO SOUND PRESSURE LEVELS OVER 100dB MAY CAUSE PERMANENT
HEARING LOSS. HIGH POWERED AUTOSOUND SYSTEMS MAY PRODUCE SOUND PRESSURE LEVELS
WELL OVER 130dB. USE COMMON SENSE AND PRACTICE SAFE SOUND.

TABLE OF CONTENTS
Introduction ..............................................................................................................................................................1
Punch Accessory Pack ..............................................................................................................................................1
Technical Design Features ........................................................................................................................................2
250x2Design Features ..............................................................................................................................................5
250m Design Features...............................................................................................................................................7
Installation Considerations ........................................................................................................................................9
Mounting Locations ................................................................................................................................................10
Battery and Charging...............................................................................................................................................10
Wiring the System ...................................................................................................................................................11
Using the XCard......................................................................................................................................................13
Customizing the XCard ...........................................................................................................................................13
XCard Resistor Chart ...............................................................................................................................................14
250x2Installation....................................................................................................................................................15
Using the 250x2Internal Switching Network...........................................................................................................18
Using the 250x2Balanced Line Inputs.....................................................................................................................23
250m Installation ....................................................................................................................................................25
Using the 250m Internal Switching Network ...........................................................................................................30
System Diagrams.....................................................................................................................................................33
Rockford Fosgate Accessories..................................................................................................................................37
Troubleshooting ......................................................................................................................................................42
Autosound 2000’s Quick Check for Troubleshooting ..............................................................................................45
250x2Specifications................................................................................................................................................47
250m Specifications................................................................................................................................................48
Warranty Information..............................................................................................................................................49
International Information.........................................................................................................................................50
GETTING STARTED
Welcome to Rockford Fosgate! This manual is designed to provide information for the owner, salesperson and
installer.Forthoseofyouwhowantquickinformationonhowtoinstallthisproductpleaseturntothe Installation
section of this manual or refer to the icons listed below. Other information can be located by using the Table of
Contents. We, at Rockford Fosgate, have worked very hard to make sure all the information in this manual is
current.But, aswe areconstantly findingnew waysto improveour product,this information issubject tochange
without notice.
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Sections marked
ADVANCED
OPERATION
include in-depth
technical information
Sections marked
INSTALLATION
include “slam dunk”
wiring connections
Sections marked
TROUBLESHOOTING
include recommendations
for curing installation
problems
TROUBLE-S
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– 1 –
PUNCH AMPLIFIER ACCESSORY PACK
The accessory pack shipped with the “250 series” Power amplifiers include the mounting hardware necessary
to secure it to the vehicle as well as attaching the end caps.
Installation & Operation Manual
Punch Verification Certificate
(8) Allen Head screws for speaker and power connectors (250x2)
(6) Allen Head screws for speaker and power connectors (250m)
(4) Mounting screws for end caps
(4) Mounting screws for amplifier
(1) Allen wrench 7/64"
(1) Allen wrench 3/32"
The “250 Series” Power amplifiers represent the best Rock-
ford Fosgate has to offer! Our engineers devised technical
featureswhichwould beconsideredoverkill byotheraudio
manufacturers, but not at Rockford Fosgate! Trans•
nova
,
DIABLOandTOPAZ,exclusivelydesignedbyRockford,are
just a few of these features which are described in the
Technical Design Features section of this manual.
The
250x
2
is atwo-channel amplifier
whichis optimizedto
drive 2Ωstereo and 4Ωbridged loads. The
250m is a single
channel amplifier
optimized to drive a 2Ω(single amp) or a
4Ωbridged load (pair of amps bridged to a single load).
The 250x
2
and 250m utilize Rockford's innovative tech-
nologies for awesome sound quality, reliable performance
andtremendousamountsofoutputpower.The“250Series”
representexactlywhatRockfordFosgatedesigns:
CarAudio
for Fanatics!
Our Dream

– 2 –
TECHNICAL DESIGN FEATURES
Many of the solutions to common design problems encountered by Rockford Fosgate engineers created entire
newcircuitdesignsaswellasnewwaystoconstructthePunch250x2and250mPowerAmplifiers.Inourflagship
amplifiers, no expense was spared in design and construction from the unique circuitry design to the
manufacturingprocessthathasproventobetheindustryreferenceformanyyears.Describedbelowarejustsome
of the accomplishments achieved by our engineering and manufacturing staff.
◆trans• nova (TRANSconductance NOdal Voltage Amplifier)
Thetrans• nova (TRANSconductanceNOdalVoltageAmplifier)isapatentedcircuit(U.S.Patent4,467,288)that
allowstheaudiosignaltopassthroughtheamplifierat lowvoltage .Eachamplifierchannelutilizesitsown“fully
floating”power supply and is configured to increase power gain. The increase in power gain allows the drive
stage to operate at a lower voltage. A low voltage drive stage is the same principle used in high quality
preamplifiers to produce high linearity and wide bandwidth.
E-I I-E
trans•nova circuitry
The resulting design utilizes an output stage with a simpler gain structure and a shorter total signal path than
conventional high voltage (bi-polar) designs. The number of stages is reduced from five or more to three. The
outputstage isfurther refinedinto a trans-impedancestage (currentto voltageconverter) toachieve ashort loop
(fast)negativefeedback.Theoutputstageisdrivencooperativelybyatransconductancestage(voltagetocurrent
converter).
THE RESULT: Superior sound quality, greater efficiency and higher reliability.
◆DIABLO (Dynamically Invariant A-B Linear Operation)
DIABLO (Dynamically Invariant A-BLinear Operation - patent application in process) is an important advance
in circuit design which reduces high frequency distortion. Amplifiers which utilize a large array of output
MOSFETscauseahighcapacitiveloadonthedriverstage.Thisloadcanmakethehighfrequenciessoundharsh.
The DIABLO circuit eliminates high frequency distortion by allowing the driver to operate with 20dB or more
of current headroom, whereas traditional drives have only 6dB of current headroom.
THE RESULT: Lower distortion and greater inherent stability.
◆TOPAZ (Tracking Operation Pre-Amplifier Zone)
The TOPAZ (Tracking Operation Pre-Amplifier Zone) circuitry solves ground loop noise problems common to
automotive amplifier design. This innovative new development allows vastly improved isolation of the input
signalgrounds from thepower supply groundof theamplifier. This isaccomplished byallowing the sourceunit
to control the potential “environment”of the entire input structure or “zone”of the amplifier. This process
improves the noise rejection of the amplifier by 30-40dB –an astounding 20-100 times better than amplifiers
without TOPAZ.
THE RESULT: Elimination of troublesome ground loop noise between source and amplifier.

– 3 –
◆DSM (Discrete Surface Mount Technology)
The DSM (DiscreteSurfaceMount)manufacturingprocesscombinestheadvantagesofbothdiscretecomponents
andintegratedcircuitry.RockfordFosgateistheonlyAmericanamplifiermanufacturertohaveinvestedmillions
into this process. DSM components differ from conventional discrete components in different ways. They are
more compact, more rugged, and they efficiently dissipate generated heat. Using them wherever appropriate
allowstheadvantages associatedwith discretecircuitrytobe retainedwhilealsoproviding roomforbothhighly
advancedprocessingfeaturesandgenerousPCboardcopperpathswhereneeded.Theirshortlead-outstructures
allow maximum audio performance and highest signal-to-noise ratios to be obtained in amplifiers of desirable
package size without resorting to “amplifier-on-a-chip”shortcuts. These advantages are shown below in Figure 1.
Figure 1
Thru-Hole Surface Mount
Component
Solder Solder
PC Board PC Board
THE RESULT: Less connections, improved reliability, shorter signal paths, superior signal-to-noise ratio and
awesome sonic performance.
◆XCard (Internal Crossover)
The Power amplifiers utilize internal active crossovers. These crossovers have many performance advantages
such as using discrete components for exact frequency adjustments which are far superior to potentiometers.
Additionally, the XCard can be configured for high-pass, low-pass and full range operation. With slight
modification, many crossover frequencies and slope configurations can be achieved.
THE RESULT: Increased system design flexibility with a precise electronic crossover without the limitations of
conventional potentiometer designs.
◆Stereo Pass-Thru
The Pass-Thru output provides a convenient source for daisy-chaining an additional amplifier without the need
forextraRCAcablesor“Y”adapters.The250mPass-ThruprovidesconstantFullRangestereooutput.The250x2
has the ability to provide constant Full Range stereo output as well as distribute one of its internal XCards to the
Pass-Thru for a dedicated High-Pass or Low-Pass output.
THE RESULT: Convenient signal level output for adding extra amplifiers.

– 4 –
Differential inputs only amplify the difference between two con-
ductors.Note: thenoisespikes appearon boththe centerconduc-
tor and the outer shield and therefore are not amplified.
Center
Conductor
Outer
Shield
RCA Input Differential
Input
Figure 2
◆Balanced Line Inputs (250x2)
Using the 250x2with the BLT (Balanced Line Transmitter)
provides the last word in achievable rejection of noise
inducedinthecablebetweenthesourceandtheamplifier.
The differential input circuitry (Figure 2) used in the bal-
anced input system rejects whatever signals are common
to both of the shielded, twisted-pair conductors. Balanced
lineisuniversalinconcertinstallationswherethestageand
mixing consoles are hundreds of feet apart. Long signal
cables and electrically-noisy environments make signal
integrity and noise rejection an extremely difficult challenge.
THE RESULT: Quiet transmission of audio from source to amplifier.
◆NOMAD (NOn-Multiplying Advanced Decision)
The Power amplifiers use an analog computer process to absolutely maximize safe output power under all
operating conditions. The innovative
NOMAD (NOn-Multiplying Advanced Decision) system is the most
sophisticated version of this technique ever used, bringing previously unavailable levels of accuracy, stability,
temperature immunity and reliability to this critical process. NOMAD makes advanced decisions based on
devicevoltagestopreciselycontroltheawesomelevelsofcurrentavailableintheoutputMOSFETstosafevalues
–but only when absolutely needed.
THE RESULT: Extremely fast protection system that always protects the amplifier and never degrades the sound.
◆MOSFET Devices (Metal Oxide Semiconductor Field Effect Transistor)
Rockford Fosgate is one of the few manufacturers in any of the sound communities to utilize MOSFET devices
in both the power supply and the output stages . MOSFET (Metal Oxide Semiconductor Field Effect Transistor)
devices offer several important inherent advantages over the 30 year old technology of bi-polar design. These
advantages include: thermal stability, switching speed, ultra low output impedance and wider bandwidth
linearity.In addition,MOSFETand vacuumtubes sharemany importantoperatingcharacteristics. However,the
MOSFET device is much faster, wider in bandwidth, measurably lower in distortion and far more linear than
vacuum tubes.
THE RESULT: Operational characteristics of vacuum tubes without the performance limitations of tube design.
◆ITS (Increased Thermal Stability)
The ITS (Increased Thermal Stability) Power Supply design is new in Rockford Fosgate amplifiers. A major
problem associated with any amplifier design is how to get rid of the heat generated by its circuitry. Clearly, it
ishighlydesirable tominimizethe amountofheat generatedinthe firstplace.The “250series”Poweramplifiers
employa new toroidalpower transformer designin which thehigh currentinput leads arecarried directly tothe
switching power MOSFETs. This both minimizes PC board heating and takes advantage of natural air cooling of
these leads.
THE RESULT: Maximizes power supply efficiency by eliminating unnecessary heat generation.

250X2DESIGN FEATURES
1. Cast Aluminum Heatsink – The cast aluminum heatsink of the Punch Power amplifier dissipates heat
generated by the amplifier's circuitry. The inherent advantage of casting provides a 30% improvement of
cooling over conventional extrusion heatsink designs.
2. End Caps – Interchangeable end caps conceal the wiring and input cables, giving the amplifier a clean
“stealth”look.
– 5 –
Speaker
+ L –
R
Unbal.
Pass
Thru
R
L (Mono)
Speaker
–R +
Bal.
Input
L
0°-180
°
EZ-180°-0 °
Bridged
REM Dual GNDDual B+
Power
GainGain
Bal.
16 5 4 4 17
3 13 8
10
6
9
7
10
312
Punch Status
Display
3. Speaker Terminals – The heavy duty, gold-plated terminal block connectors (+ and –) will accept wire
sizesfrom8AWGto18AWG.Thesegold-platedconnectorsareimmunetocorrosionthatcancausesignal
deterioration.
4. Power Terminals – Thedual powerandground connectorsonthePunch Poweramplifierare gold-plated
and will accommodate up to two 8 AWG wires maximizing the input current capability of the amplifier.
5. REM Terminal – This gold-plated spade terminal is used for the AP (auto power) or remote turn on of the
Punch 250x2Power amplifier.
6. RCAInputJacks–TheindustrystandardRCAjackprovidesaneasyconnectionforsignallevelinput.They
are gold-plated to resist the signal degradation caused by corrosion.
7. Balanced Line Input– Thisinput willallow thebalanced inputs tobe usedin conjunctionwith thePunch
250x2Power amplifier to provide better noise rejection.
8. Signal Input Switch – This switch allows selection of either the RCA or Balanced Line inputs.
9. RCA Pass-Thru Jacks – The Pass-Thru provides a convenient source for daisychaining an additional
amplifier. This eliminates the need for additional RCA cables or “Y”adapters. One of the internal
crossoverscanbedesignatedtothePassThruoutputcreatingadedicatedlow-pass,high-pass,orfullrange
output.

10. Input Sensitivity Controls – The input level controls are preset for 500mV which will match the output
of most source units. They can be adjusted to match input levels ranging from 300mV to 5V.
11. Internal Crossovers – These built-in crossover cards are configurable for a multitude of operating
frequencies.The orientation ofthe card inits socketdetermines its functionof high-pass, low-passor full
range operation.
12. E-Z Bridge Switch / 0°-180°Phase Switch – This dual purpose switch enables you to E-Z bridge the
amplifier or invert the signal phase of the right channel.
13. Phase Switch – This switch enables you to easily invert the phase of the left channel without having to
disconnect the speaker wires.
14. Crossover Switching – These internal switches allow the crossover to be distributed to the amplifier and
Pass-Thru in many different configurations.
15. Audiophile Bypass – One of the crossover switching configurations allows the internal crossover circuit
to be bypassed, maintaining Audiophile sound quality due to a shorter signal path.
16. LED Power Indicator – The LED gives a visual indication of the status of the amplifier, lighting when the
unit is turned on.
17. PunchStatusDisplay– TheRJ11interfaceallowsconnection ofanLED displayusedtomonitor amplifier
performance.
– 6 –
Low-Pass Full RangeHigh-Pass
ROCKFORD CORPORATION
MADE IN THE USA
®
®
AMPLIFIER
XCard 1 XCard 2
Audiophile Bypass
Not Used
XCard 1 XCard 2
Pass Thru
XCard Options
XCard 1 XCard 2
11
14 & 15
XCard 1 XCard 2
Amplifier
XCard 1 XCard 2
XCard Options
Not Used
Audiophile Bypass
Not Used
Amp Only
Pass Thru
Amplifier Amplifier
HP
➝
➝
LP
HP
➝
➝
LP FULL
↕
POWER
250
®
*Bridging Note: The Punch 250x
2
can be
bridged in many configurations. Refer to your
owner's manual to determine which mode will
work best in your system.
125 Watts X 2 into 4 Ohms
with less than 0.05% THD + N from 20-20kHz
225 Watts X 2 into 2 Ohms
with less than 0.10% THD + N from 20-20kHz

250m DESIGN FEATURES
1. Cast Aluminum Heatsink – The cast aluminum heatsink of the Punch Power amplifier dissipates heat
generated by the amplifier's circuitry. The inherent advantage of casting provides a 30% improvement of
cooling over conventional extrusion heatsink designs.
2. End Caps – Interchangeable end caps conceal the wiring and input cables, giving the amplifier a clean
“stealth” look.
– 7 –
R Pass ThruL Pass Thru
RL (Mono)
REM Dual GNDDual B+
Power
Gain
5 4 4
3
6
8
13 1112
Punch
Status
Display
X-Over
24dB/12dB/0dB
L + R / L
(Mono)
14
9 7
0°–180°
Speaker
– +
3. Speaker Terminals – The heavy duty, gold-plated terminal block connectors (+ and –) will accept wire
sizesfrom8AWGto18AWG.Thesegold-platedconnectorsareimmunetocorrosionthatcancausesignal
deterioration.
4. Power Terminals – Thedual powerandground connectorsonthe PunchPoweramplifier are gold-plated
and will accommodate up to two 8 AWG wires maximizing the input current capability of the amplifier.
5. REM Terminal – This gold-plated spade terminal is used for the AP (auto power) or remote turn on of the
Punch 250m Power amplifier.
6. RCAInput Jacks–TheindustrystandardRCAjackprovidesaneasyconnectionforsignallevelinput.They
are gold-plated to resist the signal degradation caused by corrosion.
7. Summed Stereo / Mono Switch – This switch is used to select whether 1 or 2 signal inputs will be used
to drive the amplifier.
8. Pass-Thru RCA Jacks – The Pass-Thru provides a convenient source for daisychaining an additional
amplifier.Thiseliminates theneed foradditional RCAcables or“Y” adapters.The Pass-Thru outputis Full
Range only.
9. InputSensitivityControl–Theinputlevelcontrolispresetfor500mVwhichwillmatchtheoutputofmost
source units. It can be adjusted to match input levels ranging from 300mV to 5V.

10. Internal Crossover – Thisbuilt-in crossovercard isconfigurablefor amultitudeof operatingfrequencies.
The orientation of the card in its socket determines the function of high-pass, low-pass or full range
operation.
11. Phase Switch – This switch enables you to easily invert the phase without having to disconnect the
speaker wires.
12. Crossover Switch – Thismulti-function switchenablesyou toselect a12dBper octaveslope or24dBper
octave slope of the internal crossover. When switched to 0dB, the internal crossover circuit can be
bypassed, maintaining Audiophile sound quality due to a shorter signal path.
13. LED Power Indicator – The LED illuminates when the unit is turned on.
14. PunchStatus Display – TheRJ11 interfaceallowsconnection ofanLEDdisplay usedtomonitoramplifier
performance.
– 8 –
Low Pass Full RangeHigh Pass
FULL
↕
ROCKFORD CORPORATION
MADE IN THE USA
®
XCard 1
10
+–
Do Not Chassis
Ground Any
Speaker Wire.
+–
HP
➝
➝
LP
HP
➝
➝
LP
250 Watts X 1 into 4 Ohms
with less than 0.10% THD + N from 20-20kHz
500 Watts X 1 into 2 Ohms
with less than 0.15% THD + N from 20-20kHz
®
250
POWER
®
AMPLIFIER

– 9 –
INSTALLATION CONSIDERATIONS
Tools Needed
The following is a list of tools you will need for installing the Punch 250x2and 250m Power amplifiers:
Allen wrenches 7/64" & 3/32" (included) Wire Cutters
Wire strippers Voltmeter
Battery post wrench Wire crimpers
Electric hand drill and assorted bits Assorted connectors
This section focuses on some of the vehicle considerations for installing your new Punch amplifier. Checking
your battery and present sound system, as well as pre-planning your system layout and best wiring routes will
save installation time. When deciding on the layout of your new system, be sure that each component will be
easily accessible for making adjustments.
Before beginning any installation, be sure to follow these simple rules:
1. Carefully read and understand the instructions before attempting to install the amplifier.
2. For safety, disconnect the negative lead from the battery prior to beginning the installation.
3. For easier assembly, we suggest you run all wires prior to mounting your amplifier in place.
4. Route all of the RCA cables close together and away from any high current wires.
5. Use high quality Connecting Punch accessories for a reliable installation and to minimize signal or
power loss.
6. Think before you drill! Be careful not to cut or drill into gas tanks, fuel lines, brake or hydraulic lines,
vacuum lines or electrical wiring when working on any vehicle.
7. Never run wires underneath the vehicle. Running the wires inside the vehicle provides for best
protection.
8. Avoidrunning wires overor throughsharp edges. Userubber or plasticgrommets toprotect any wires
routed through metal, especially the firewall.
9. ALWAYSprotectthebatteryandelectricalsystemfromdamagewithproperfusing.Installafuseholder
and fuse on the +12V power wire within 18" (45.7cm) of the battery terminal.
10. When grounding to the chassis of the vehicle, scrape all paint from the metal to ensure a good, clean
ground connection. Grounding connections should be as short as possible and always be connected
to metal that is welded to the main body, or chassis, of the vehicle.

MOUNTING LOCATIONS
The mounting location and position of your amplifier will have a great effect on its ability to dissipate the heat
generatedunder normal operation.The designof our castaluminum heatsinkserves to easily dissipate theheat
generatedoverawiderangeofoperatingconditions.However, tomaximizethe performanceofyour amplifier,
care should be taken to ensure adequate ventilation.
Trunk Mounting
Mounting the amplifier vertically on a surface with the fin grooves running up and down will provide the best
cooling of the amplifier.
Mounting the amplifier on the floor of the trunk will work but provides less cooling capability than
vertical mounting.
Mounting the amplifier upside down to the rear deck of the trunk will not provide proper cooling and will
severely affect the performance of the amplifier and is strongly
not recommended.
Passenger Compartment Mounting
Mounting the amplifier in the passenger compartment will work as long as you provide a sufficient amount of
air for the amplifier to cool itself. If you are going to mount the amplifier under the seat of the vehicle, you must
have at least 1" (2.54cm) of air gap around the amplifier's heatsink.
Mounting the amplifier with less than 1" (2.54cm) of air gap around the heatsink in the passenger compartment
will not provide proper cooling and will severely affect the performance of the amplifier and is strongly
not recommended.
Engine Compartment Mounting
Rockford Fosgate amplifiers should never be mounted in the engine compartment. Not only will this void your
warranty but could create an embarrassing situation caused by the ridicule from your friends.
– 10 –
BATTERY AND CHARGING
Amplifiers will put an increased load on the vehicle's battery and charging system. We recommend checking
your alternator and battery condition to ensure that the electrical system has enough capacity to handle the
increased load of your stereo system. Stock electrical systems which are in good condition should be able to
handle the extra load of any Rockford amplifier without problems, although battery and alternator life can be
reducedslightly.TomaximizetheperformanceofyourRockfordFosgateamplifier,wesuggesttheuseofaheavy
duty battery, high output alternator and an energy storage capacitor.

WIRING THE SYSTEM
CAUTION: Avoid running power wires near the low level input cables, antenna, power leads, sensitive
equipmentorharnesses.Thepowerwirescarrysubstantialcurrentandcouldinducenoiseintotheaudiosystem.
1. Configure the internal XCard crossovers prior to installation. Refer to the “Using the Internal Switching
Network” (page 18 for the 250x2and page 30 for 250m) for further information.
2. Plan the wire routing. Take care when running signal level RCA cables to keep them close together but
isolated from the amplifier's power cables and any high power auto accessories, especially electric motors.
Thisisdone topreventcouplingthenoise fromradiatedelectricalfields intotheaudiosignal. Whenfeeding
the wires through the firewall or any metal barrier, protect them with plastic or rubber grommets to prevent
short circuits. Leave the wires long at this point to adjust for a precise fit at a later time.
3. PreparethePowercableforattachmenttotheamplifierbystripping
5/8"ofinsulationfromtheendofthewire.Theuseof8gaugepower
cablecaninterferewiththeinstallationoftheendcaps.Properwire
dress can prevent this from occurring. To prevent the wire from
fraying,strip theinsulation ata 45°angle.Insert thebared wireinto
theB+terminalwiththelong sideof theinsulation onthe top.Bend
the cable down at a 90°angle. Tighten the set screw to secure the
cable in place. We recommend using (2) 8 gauge cables for power
and for ground. This will give you the best performance possible.
4. Strip 3/8" from the battery end of the power cable and crimp a large ring terminal to the cable. Use the ring
terminal to connect to the battery positive terminal. Do not install the fuse at this time.
5. Prepare a length of cable to be used for the ground connection. Strip 5/8" of insulation from the end of the
cableasdescribedaboveandconnecttotheappropriateterminaloftheamplifier.Preparethechassisground
by scraping any paint from the metal surface and thoroughly clean the area of all dirt and grease. Strip the
otherendofthewireandattacharingconnector.Fastenthecabletothechassisusinganon-anodizedscrew
and a star washer.
6. Prepare the REM turn-on wire for connection to the amplifier by stripping 5/8" of insulation from the wire
end and crimping an insulated spade connector in place. Slide the connector over the REM terminal on the
amplifier. Connect the other end of the REM wire to a switched 12 volt positive source. The switched signal
is usually taken from the source unit's auto antenna or the accessory lead. If the source unit does not have
these outputs available, the recommended solution is to wire a mechanical switch in line with a 12 volt
source to activate the amplifier.
7. Securely mount the amplifier (with supplied screws) to the vehicle or amp rack. Be careful not to mount the
amplifier on cardboard or plastic panels. Doing so may enable the screws to pull out from the panel due
to road vibrations or sudden vehicle stops.
8. Connect the source signal to the amplifier by plugging the RCA cables into the input jack(s) at the amplifier.
If using Balanced Line Inputs, refer to page 23.
9. Connect the speakers. Strip the speaker wires 5/8" and insert into the appropriate terminal on the amplifier.
Insert the bared wire into the speaker terminal and tighten the set screw to secure into place. Be sure to
maintain proper speaker polarity. DO NOT chassis ground any of the speaker leads as unstable operation
may result.
– 11 –
><
5/8"
INSULATION
STRIP WIRE
>
>
AMP
>

10. Perform a final check of the completed system wiring to ensure that all connections are accurate. Check all
power and ground connections for frayed wires and loose connections which could cause problems from
road vibrations.
11. After the final inspection is complete, install the power fuse and enjoy listening. During the initial listening
period, you may need to “fine tune” any phasing and level settings within your particular vehicle. To aid in
this procedure, play a track with high musical content and cruise around your neighborhood. After fully
evaluatingthetransientresponseofyoursystemandmakinganyfinaladjustments,allyourneighborswithin
a1mile radiuswillassumethatyou havejustsuccessfullycompleted anotherupgradetoyour audiosystem
for which they will probably spill thumbtacks on your driveway.
– 12 –
NOTICE!
Amplifiers using the trans• nova topology improve in sound quality after
warming up. We recommend operating the 250x2and 250m for approxi-
mately15minutespriortoevaluationunderjudgingcriteriaortune-upsto
establish its normal operating temperature.
* Your friends will call it MAGIC, you can call it Rockford technology! *

USING THE XCARD
Thecrossover functions arecontrolled through theuse of anXCard and canbe set forhigh-pass, low-pass orfull
rangeoperation.The100HzXCardshippedwithyouramplifierissetforFullRange.Eachcrossovercardhastwo
faces: one face operates Full Range, the other has arrows to indicate the edge for selecting HP (high-pass) or LP
(low-pass)operation. Orientthe cardwith thedesired operatingedge, indicatedby thearrow, towardthe socket
terminals inside the amplifier. Firmly, but carefully, plug the card into the socket.
– 13 –
CUSTOMIZING THE XCARD
7234
fo
3386
fo= R (in kΩ) for .047µf cap
= R (in kΩ) for .022µf cap
Crossover Card
High Pass
Low Pass
Full Range
R1 R2 R1 R2
FULL
1
2πfoc
The crossover point can be altered by changing the resistor value. Use the following formula to select the
appropriate resistor value to be placed on the XCard.
Low-Pass Full RangeHigh-Pass
FULL
↕
HP
➝
➝
LP
HP
➝
➝
LP
The actual formula is: R =
Where: R = Ω
fo= desired crossover frequency
c = capacitor in farads
ex: .047 x 10-6 for .047mf cap
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XCARD RESISTOR CHART
– 14 –
Frequency R1 R2
20Hz 169kΩ169kΩ
25Hz 133kΩ133kΩ
30Hz 110kΩ110kΩ
35Hz 95.3kΩ95.3Ω
40Hz 84.5kΩ84.5kΩ
45Hz 75kΩ75kΩ
50Hz 68.1kΩ68.1kΩ
55Hz 61.9kΩ61.9kΩ
60Hz 56.2kΩ56.2kΩ
65Hz 52.3kΩ52.3kΩ
70Hz 48.7kΩ48.7kΩ
75Hz 45.3kΩ45.3kΩ
80Hz 42.2kΩ42.2kΩ
84Hz 40.2kΩ40.2kΩ
90Hz 37.4kΩ37.4kΩ
200Hz 16.9kΩ16.9kΩ
300Hz 11.3kΩ11.3kΩ
400Hz 8.45kΩ8.45kΩ
500Hz 6.65kΩ6.65kΩ
600Hz 5.62kΩ5.62kΩ
700Hz 4.75kΩ4.75kΩ
800Hz 4.22kΩ4.22kΩ
900Hz 3.74kΩ3.74kΩ
1kHz 3.40kΩ3.40kΩ
1.2kHz 2.80kΩ2.80kΩ
2kHz 1.69kΩ1.69kΩ
3kHz 1.10kΩ1.10kΩ
4kHz 845Ω845Ω
5kHz 665Ω665Ω
6kHz 562Ω562Ω
7kHz 487Ω487Ω
8kHz 422Ω422Ω
Butterworth Alignment Q = .707
1% resistors used with 0.047µµ
µµ
µF capacitors
Frequency R1 R2
21Hz 160kΩ160kΩ
26Hz 130kΩ130kΩ
30.8Hz 110kΩ110kΩ
37Hz 91kΩ91Ω
41Hz 82kΩ82kΩ
45Hz 75kΩ75kΩ
49.8Hz 68kΩ68kΩ
54.6Hz 62kΩ62kΩ
60.5Hz 56kΩ56kΩ
66.4Hz 51kΩ51kΩ
72Hz 47kΩ47kΩ
N/A N/A N/A
78.7Hz 43kΩ43kΩ
86.8Hz 39kΩ39kΩ
94Hz 36kΩ36kΩ
212Hz 16kΩ16kΩ
308Hz 11kΩ11kΩ
413Hz 8.2kΩ8.2kΩ
498Hz 6.8kΩ6.8kΩ
605Hz 5.6kΩ5.6kΩ
720Hz 4.7kΩ4.7kΩ
787Hz 4.3kΩ4.3kΩ
940Hz 3.6kΩ3.6kΩ
1kHz 3.3kΩ3.3kΩ
1.2kHz 2.7kΩ2.7kΩ
2.1kHz 1.6kΩ1.6kΩ
3kHz 1.1kΩ1.1kΩ
4.1kHz 820Ω820Ω
5kHz 680Ω680Ω
6kHz 560Ω560Ω
7.2kHz 470Ω470Ω
7.9kHz 430Ω430Ω
Butterworth Alignment Q = .707
5% resistors used with 0.047µµ
µµ
µF capacitors
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250X2INSTALLATION
– 15 –
*Keep ground connections as close to each other as possible.
*Keep ground connections as close to each other as possible.
I
N
S
T
A
L
L
A
T
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O
N
® ®
REM
Power
Connect to remote
turn-on lead of
source unit.
Connect to B+ of battery
with a 60 amp fuse.
Connect to chassis
ground of vehicle*
Connect to
optional
PSD
Punch Status
Display
Dual B+ Dual GND
Less than 18"
+ –
250x2Power Connections (Option #2)
250x2Power Connections (Option #1)
REM
Power
Connect to remote
turn-on lead of
source unit.
Connect to B+ of battery
with two 30 amp fuses.
Connect to chassis
ground of vehicle*
Connect to
optional
PSD
Punch Status
Display
Dual B+ Dual GND
Less than 18"
+ –

– 16 –
•RCA inputs are connected to both left and right channels
•Signal Input Switch selected to
Unbalanced for RCA input
•Left Phase Switch set to
0 °
• Right Phase Switch set to 180 ° for stereo/mono operation
•All speaker polarity on right channel is inverted to correct for signal phase
•Gain for left and right channels set
equally to balance the subwoofer
•Impedance for
each channel should be 2 Ω minimum
•Impedance for bridged channel should be 4 Ω minimum
•XCard is in Full Range position
Stereo/Mono Operation
Stereo Operation
I
N
S
T
A
L
L
A
T
I
O
N
® ®
R
Unbal.
Pass
Thru
Bal.
Input
L
0°-180
°
EZ-180°-0 °
Bridged
Gain
Bal.
Gain
–
+
RCA
Input
+
–
Speaker
+ L –
L (Mono)
Speaker
–R +
R
2ΩMin. 2ΩMin.
•RCA inputs are connected to both left and right channels
•Signal Input Switch selected to
Unbalanced for RCA input
•Left Phase Switch set to
0 °
•Right Phase Switch set to 0 °
•Gain for left and right channels operate independently
•Impedance for each channel should be 2 Ω minimum
•XCard can be High-Pass, Low-Pass or Full Range position
R
Unbal.
Pass
Thru
Bal.
Input
L
0°-180
°
EZ-180°-0 °
Bridged
Gain
Bal.
Gain
–
+
RCA
Input
+
–
4Ωmin.
+–
+
Speaker
Terminal
–
Speaker
Terminal
Speaker
+ L –Speaker –R +
L (Mono) R
2Ωmin. 2Ωmin.