Rockford RF 4.6x Owner's Manual

® ®

car audio

for

fanatics

100 Watt Amplifier

.3

Installation Installation

Installation

Installation Installation

2-channel

.6

.6

150 Watt Amplifier

2-channel w/crossover

300 Watt Amplifier

4-channel w/crossover

and and

and

and and

OperationOperation

Operation

OperationOperation

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). Please read your
warranty and retain your receipt and original carton for possible future use.

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 Rockford Fosgate image order your Rockford
wearables, which include everything from T-shirts and jackets to hats and sunglasses.

To get a free brochure on Rockford Fosgate products and Rockford accessories, in the
U.S. call 602-967-3565 or FAX [phone]. For all other countries, call +001-602­967-3565 or FAX [phone].

PRACTICE SAFE SOUND™

CONTINUOUS EXPOSURE TO SOUND PRESSURE LEVELS OVER

100dB MAY CAUSE PERMANENT HEARING LOSS. HIGH

POWERED
PRESSURE
AND

If, after reading your manual, you still have questions regarding this product,
we recommend that you see your Rockford Fosgate dealer. If you need further
assistance, you can call us direct at 1-800-795-2385. Be sure to have your serial
number, model number and date of purchase available when you call.

The serial number can be found on the outside of the box. Please record it in
the space provided below as your permanent record. This will serve as
verification of your factory warranty and may become useful in recovering your
amplifier if it is ever stolen.

Serial Number: ________________________________
Model Number:________________________________

AUTOSOUND SYSTEMS MAY PRODUCE SOUND

LEVELS WELL OVER 130dB. USE COMMON SENSE

PRACTICE SAFE SOUND.

TABLE OF CONTENTS

Introduction ............................................................................................. 1

Accessory Pack ........................................................................................ 1

Technical Design Features .......................................................................1

2.3, 2.6x, 4.6x Design Features ................................................................5

Installation Considerations ....................................................................... 7

Mounting Location................................................................................... 8

Battery and Charging................................................................................9

Wiring the System ....................................................................................9

Using Passive Crossovers .......................................................................11

Table of Crossover Component Values................................................... 12

Using the XCard..................................................................................... 13

Customizing the XCard ..........................................................................13

Resistor Chart......................................................................................... 14

XCard Access .........................................................................................15

2.3 & 2.6x Installation............................................................................ 16

4.6x Installation .....................................................................................19

System Diagrams....................................................................................24

Troubleshooting .....................................................................................28

Dynamic Power Measurements.............................................................. 31

Specifications......................................................................................... 33

Warranty Information............................................................................. 35

International Information........................................................................36

G

ETTING STARTED

Welcome to Rockford Fosgate! This manual is designed to provide
information for the owner, salesperson and installer. For those of you
who want quick information on how to install this product, please turn
to the

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, as we are constantly finding
new ways to improve our product, this information is subject to change
without notice.

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Sections marked

ADVANCED OPERATION

include in-depth

technical information

include “slam dunk”

® ®

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Sections marked

INSTALLATION

wiring connections

TROUBLE-

Sections marked

TROUBLESHOOTING

include recommendations

for curing

installation problems

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INTRODUCTION

This manual provides information on the features, installation and opera­tion of the Rockford Fosgate 2.3, 2.6x and 4.6x Amplifiers. We suggest you
save this manual for future reference.

We strongly recommend you have your Authorized Rockford Fosgate
Dealer install your new Rockford Fosgate amplifier. If you do choose to
install your amplifier yourself, please be sure to read the entire manual
before beginning.

ACCESSORY PACK

Installation & Operation Manual
(1) Fuseholder
(1) ATC 10 Amp Fuse (2.3)
(1) ATC 20 Amp Fuse (2.6x)
(1) ATC 30 Amp Fuse (4.6x)
(1) 3/32" Allen Wrench

TECHNICAL DESIGN FEATURES

◆ TRANS•ANA

(TRANSconductance Active Nodal Amplifier)

The

TRANS•ANA

circuit that allows the audio signal to pass through the amplifier at low
voltage. The signal is directly level-shifted to the fixed high voltage
rails via a pair of driver transistors. Signal linearity is assured by an
active node formed by the drive transistors at ultrasonic frequencies.
This allows amplifier performance similar to trans•
highly stable and linear while utilizing the advantages of a non­floating power supply.

THE RESULT: An extended frequency bandwidth accurately supplied
to the output stages of the amplifier.

(TRANSconductance Active Nodal Amplifier) is a

nova

which is

– 1 –

◆ TOP AZ (Tracking Operation Pre-Amplifier Zone)

The

TOPAZ

ground loop noise problems common to automotive amplifier design.
This innovative new development allows vastly improved isolation of
the input signal grounds from the power supply ground of the
amplifier. This is accomplished by allowing the source unit 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 30-100 times better than amplifiers
without TOPAZ.

THE RESULT: Elimination of troublesome ground loop noise between
source and amplifier.

(Tracking Operation Pre-Amplifier Zone) circuitry solves

◆ MOSFET Devices

Rockford Fosgate is one of the few manufacturers in the sound
community to utilize MOSFET devices in both the
the

output stages. MOSFET

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, MOSFETs operate
very similarly to vacuum tubes in that they are more linear than bi­polar transistors. However, MOSFETs can deliver the midrange clarity
without the limitations of transient response and high frequency
phase shifting normally associated with tube operation.

(Metal Oxide Semiconductor Field Effect

power supply

and

THE RESULT: Operational characteristics similar to vacuum tubes

without the performance limitations of tube design.

– 2 –

◆ DSM (Discrete Surface Mount) Technology

The

DSM

(Discrete Surface Mount) manufacturing process combines
the advantages of both discrete components and integrated circuitry.
Rockford Fosgate is the only American amplifier manufacturer to have
invested millions 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 allows the advantages associated
with discrete circuitry to be retained while also providing room for
both highly advanced processing features and generous PC board
copper paths where needed. Their short lead-out structures 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

PC

Board

Thru-Hole Surface Mount

THE RESULT: Fewer connections, improved reliability, shorter signal
paths, superior signal-to-noise ratio and awesome sonic performance.

Solder

Component

Solder

PC

Board

◆ NOMAD (NOn-Multiplying Advanced Decision)

All Rockford Fosgate amplifiers use an
maximize safe output power under all operating conditions. The
innovative
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 device voltages to precisely control the
awesome levels of current available in the output MOSFETs to safe
values – but only when absolutely needed.

NOMAD

(NOn-Multiplying Advanced Decision) system

analog computer process

to

THE RESULT: Extremely fast protection system that always protects
the amplifier and never degrades the sound.

– 3 –

◆ High Level Inputs

The high level inputs on the Rockford Fosgate amplifiers convert the
speaker line outputs (high level) to preamp line inputs (low level).
This allows amplifier compatibility with a variety of source units as
well as the ability to integrate into factory systems without the need
for external adapters.

THE RESULT: Allows compatibility with factory and aftermarket
source units.

◆ XCard Crossover (2.6x & 4.6x)

The 2.6x and 4.6x 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.

– 4 –

2.3, 2.6X, 4.6X DESIGN FEATURES

1

Bias

Gain
L&R

5 3

6

Bias

CAUTION!

Do Not Adjust

8

L R L R

+– +–

High In

Input

1

Bias

Do Not Adjust

LED

GND

4 7

CAUTION!

Speaker Speaker

L+ L-

R+ R-

Bias

.3

2

&

B+

.6

REM GND

CAUTION!

Any adjustment to

the Bias controls may damage

your amplifier and will void

your warranty.

Bias

Do Not Adjust

CAUTION!

Bias

.6

Gain
L&R

6

L R

5 3

Input

8

High In

LR

+– +–

GND

4

Speaker Speaker

LED

LF+ LF-

7

RF+ RF-

B+

REM GND

2

– 5 –

Speaker

LR– LR+

Speaker

RR– RR+

8

Gain

L&R

5 3

Input

L R

High In

LR

+– +–

GND

4

6

1. Extruded Heatsink

The extruded aluminum heatsink of the RF amplifier dissipates
heat generated by the amplifier's circuitry.

2. Power/Speaker Barrier Strip

The barrier strip uses screw terminals that will accept #10 spade
lugs or bare speaker and power wire sizes from 10-18 AWG.
These gold-plated connectors are immune to corrosion that will
cause signal degradation.

3. RCA Input Jacks

The industry standard RCA jack provides an easy connection for
signal level input. They are gold-plated to resist the signal
degradation caused by corrosion.

4. High Level Inputs

The high level input connectors accept 1/8" spade lugs for the
connection of a source unit that has only speaker line (high level)
outputs.

5. 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
output levels from a variety of source units.

6. Internal Crossover

The built-in crossover card is configurable for a multitude of
operating frequencies. The orientation of the card in its socket
determines its function of high-pass, low-pass or full range
operation.

7. LED Power Indicator

The LED gives a visual indication of the status of the amplifier,
lighting when the unit is turned on.

8. Bias Controls

The Bias controls are preset at the factory and are not user
adjustable. CAUTION! ANY ADJUSTMENT TO THE BIAS

CONTROLS WILL VOID YOUR WARRANTY!

– 6 –

INSTALLATION CONSIDERATIONS

The following is a list of tools you will need for installing the amplifier:
Wire Cutters #2 Phillips Screwdriver

Wire Strippers Assorted wire connectors
Wire Crimpers Battery Post Wrench
Voltmeter Electric Hand Drill with assorted bits

This section focuses on some of the vehicle considerations for
installing your new 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. Be sure to 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 connectors 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 the best protection.

8. Avoid running wires over or through sharp edges. Use rubber or
plastic grommets to protect any wires routed through metal,
especially the firewall.

9. ALWAYS protect the battery and electrical system from damage
with proper fusing. Install a fuseholder and appropriate fuse on
the +12V power wire within 18” (45.7 cm) 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.

– 7 –

MOUNTING LOCATION

The mounting location and position of your amplifier will have a
great effect on its ability to dissipate the heat generated during normal
operation. The design of our aluminum heatsink serves to easily
dissipate the heat generated over a wide range of operating condi­tions. However, to maximize the performance of your 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

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.

not

recommended.

Mounting the amplifier with less than 1" (2.54cm) of air gap around
the amplifier's 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
compartment. Not only will this void your warranty but could create
an embarrassing situation caused by the ridicule from your friends.

– 8 –

never

be mounted in the engine

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 reduced slightly. To
maximize the performance of your Rockford Fosgate amplifier, we
suggest the use of a heavy duty battery, high output alternator and an
energy storage capacitor.

WIRING THE SYSTEM

CAUTION:

cables, antenna, power leads, sensitive equipment or harnesses. The
power wires carry substantial current and could induce noise into
the audio system.

• For safety, disconnect the negative lead from the battery prior to
beginning the installation.

1. Remove the cover and configure the internal XCard crossovers
prior to installation. Refer to “Using the XCard” (page 13) 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. This is done to prevent coupling the noise from
radiated electrical fields into the audio signal. When feeding 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. Prepare the Power cable for attachment to the amplifier by
stripping 1/2" of insulation from the end of the wire. Insert the
bared wire into the B+ terminal and tighten the set screw to secure
the cable in place.

NOTE: The B+ cable MUST be fused 18" or less from the vehicle's
battery. Install the fuseholder under the hood and prepare the
cable ends as stated above. Connections should be water tight.

Avoid running power wires near the low level input

– 9 –

Trim the power cable within 18" of the battery and
strip 1/2" of insulation from the end of the wire.

Cut the wire loop that is attached to the fuseholder
in half and splice the fuse into the power line
using appropriate inline connectors. Use the

section of cable that was trimmed earlier and
connect it to the other end of the fuseholder.

4. Strip 1/2" 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 the Ground cable for attachment to the amplifier by
stripping 1/2" of insulation from the end of the wire. Insert the bared
wire into the GND terminal and tighten the set screw to secure the
cable in place. Prepare the chassis ground by scraping any paint
from the metal surface and thoroughly clean the area of all dirt and
grease. Strip the other end of the wire and attach a ring connector.
Fasten the cable to the chassis using a non-anodized screw and a
star washer.

6. Prepare the REM turn-on wire for connection to the amplifier by

stripping 1/2" of insulation from the wire end. Insert the bared
wire into the REM terminal and tighten the set screw to secure the
cable into place. Connect the other end of the REM wire to a
switched 12 volt positive source. The switched voltage 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.

X

Cut
here

7. Securely mount the amplifier 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 vibration or sudden vehicle stops.

8. Connect the source signal to the amplifier by plugging the RCA

cables into the input jacks at the amplifier.

9. Connect the speakers. Strip the speaker wires 1/2" and insert 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.

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.

– 10 –

USING PASSIVE CROSSOVERS

A passive crossover is a circuit that uses capacitors and/or coils and is
placed on speaker leads between the amplifier and speaker. The
crossover delegates a specific range of frequencies to the speaker for
optimum driver performance. A crossover network can perform one of
three functions: High-Pass (capacitors), Low-Pass (inductors or coils)
and Bandpass (combination of capacitor and coil).

The most commonly used passive crossover networks are 6dB/octave
systems. These are easy to construct and require one component per
filter. Placing this filter in series with the circuit will reduce power to
the speaker by 6dB/octave above or below the crossover point
depending on whether it is a high-pass or low-pass filter. More
complex systems such as 12dB/octave or 18dB/octave can cause
impedance problems if not professionally designed.

Passive crossovers are directly dependent upon the speaker's imped­ance and component value for accuracy. When passive crossover
components are used in multiple speaker systems, the crossover's
effect on the overall impedance should be taken into consideration
along with the speaker's impedance when determining amplifier
loads.

CAUTION: The Rockford Fosgate amplifiers are not recom-

mended for impedance loads below 2Ω stereo and 4Ω bridged
(mono) loads.

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TABLE OF CROSSOVER COMPONENT VALUES

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L

6 dB/Octave Low-Pass

Freq.
Hertz

2 OHMS

L

6 dB/Octave High-Pass

Speaker Impedance

4 OHMS

C L

C

C

8 OHMS

L C

80 4.1mH 1000µF 8.2mH 500µF 16mH 250µF
100 3.1mH 800µF 6.2mH 400µF 12mH 200µF
130 2.4mH 600µF 4.7mH 300µF 10mH 150µF

200 1.6mH 400µF 3.3mH 200µF 6.8mH 100µF
260 1.2mH 300µF 2.4mH 150µF 4.7mH 75µF
400 .8mH 200µF 1.6mH 100µF 3.3mH 50µF

600 .5mH 136µF 1.0mH 68µF 2.0mH 33µF
800 .41mH 100µF .82mH 50µF 1.6mH 26µF

1000 .31mH 78µF .62mH 39µF 1.2mH 20µF

1200 .25mH 66µF .51mH 33µF 1.0mH 16µF
1800 .16mH 44µF .33mH 22µF .68mH 10µF
4000 .08mH 20µF .16mH 10µF .33mH 5µF

6000 51µH14µF .10mH 6.8µF .20mH 3.3µF
9000 34µH 9.5µF68µH 4.7µF .15mH 2.2µF

12000 25µH 6.6µF51µH 3.3µF 100µH 1.6µF

6 dB/Octave High-Pass and Low-Pass Filters

L = Low-Pass (Inductor)
C = High-Pass (Capacitor)

For more information, see your Authorized Rockford Fosgate Dealer.

– 12 –

USING THE XCARD

The crossover functions are controlled through the use of an XCard
and can be set for high-pass, low-pass or full range operation. The
100Hz XCard shipped with your amplifier is set for Full Range. Each
crossover card has two faces: one face operates Full Range, the other
has arrows to indicate the edge for selecting HP (high-pass) or LP (low­pass) operation. Orient the card with the desired operating edge,
indicated by the arrow, toward the socket terminals inside the ampli-

fier. Firmly, but carefully, plug the card into the socket.

Low-Pass Full RangeHigh-Pass

➝

LP

➝

HP

➝

HP

LP

CUSTOMIZING THE XCARD

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.

3386

7234

The actual formula is:

R =

= R (in kΩ) for .047µf cap

f

o

= R (in kΩ) for .022µf cap

f

o

1

2πfoc

C1

➝

R1

C2

FULL

Crossover Card

High Pass

C1

R2

Low Pass
Full Range

R1

C2

FULL

↕

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R2

Where: R = Ω

fo = desired crossover frequency
c = capacitor in farads
ex: .047 x 10-6 for .047mf cap

– 13 –