Rockford Fosgate 250.1 manual Balanced Line Inputs, NOMAD NOn-MultiplyingAdvanced Decision

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◆ Balanced Line Inputs (250.2)

◆ Balanced Line Inputs (250.2)

Using the 250.2 with the BLT (Balanced Line Transmitter)

 

Figure 2

RCA Input

Differential

 

 

provides the last word in achievable rejection of noise

 

Center

 

Input

 

induced in the cable between the source and the amplifier.

 

Conductor

 

 

 

 

 

 

 

 

The differential input circuitry (Figure 2) used in the bal-

 

Outer

 

 

 

anced input system rejects whatever signals are common

 

 

 

 

 

Shield

 

 

 

to both of the shielded, twisted-pair conductors. Balanced

 

Differential inputs only amplify the difference between two con-

 

line is universal in concert installations where the stage and

 

ductors. Note: the noise spikes appear on both the center conduc-

 

 

tor and the outer shield and therefore are not amplified.

 

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 device voltages to precisely control the awesome levels of current available in the output MOSFETs to safe values

–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, MOSFET and vacuum tubes share many important operating characteristics. 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 is highly desirable to minimize the amount of heat generated in the first place. The “250 series” Power amplifiers employ a new toroidal power transformer design in which the high current input leads are carried directly to the 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.

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Contents 250.1 powerpower powerPRACTICE SAFE SOUND G E T T I N G S T A R T E D TA B L E O F CO N T E N T SINTRODUCTION TO 250 SERIES Punch PowerPunch Power trans nova circuitry TECHNICAL DESIGN FEATURESDIABLO Dynamically Invariant A-BLinear Operation TOPAZ Tracking Operation Pre-AmplifierZoneDSM Discrete Surface Mount Technology Stereo Pass-ThruXCard Internal Crossover NOMAD NOn-MultiplyingAdvanced Decision Balanced Line InputsITS Increased Thermal Stability 250.2 DE S I G N FE AT U R E S PLIFIER 250.1 DE S I G N FE AT U R E S 1AMPLIFIER Tools Needed INSTALLATION CONSIDERATIONSEngine Compartment Mounting BATTERY AND CHARGINGTrunk Mounting Passenger Compartment MountingW I R I N G T H E S Y S T E M USING PASSIVE CROSSOVERS Freq TABLE OF CROSSOVER COMPONENT VALUES6 dB/Octave High-Pass 6 dB/Octave Low-PassLow-Pass US I N G T H E XCARDCU S T O M I Z I N G T H E XCA R D High-PassButterworth Alignment Q = XCA R D RESISTOR CHARTButterworth Alignment Q = 1% resistors used with 0.047∝ F capacitors250.2 Power Connections Option #1 250.2 INSTALLATION250.2 Power Connections Option #2 Right Phase Switch set to Stereo OperationStereo/Mono Operation Left Phase Switch set toRight Phase Switch set to Bridged OperationEZ-BridgedOperation Left Phase Switch set toPage XCard not required Pass-Thru uses output from XCard 250.2 uses output from XCardPage Pass-Thru Configurea12dBperConfigurea24dBperoctave and“AudiophileBypass”the filterforConnecting the BLT USING THE 250.2 BALANCED LINE INPUTSDisconnect Speakers from the Level Setting the BLT8.0 VAC Performance Characteristics250.1 Power Connections Option #1 250.1 INSTALLATION250.1 Power Connections Option #2 Phase Switch set to Mono Operationminimum orFullRange AmplifiersPowerImpedanceforeachstereochannelshouldbe2Ω minimum Stereo/Mono OperationImpedanceforbridgedchannelshouldbe4Ω minimum Pass,-High -LoworPass RangeFull Bridged Mono Operationminimum Impedanceforbridgedchannelshouldbe4ΩS W I T C H I N G N E T W O R K U S I N G T H E 250.1 SIGNAL“Audiophile Bypass” the TUNE Configure a 12dB per octave filter for theXCard LOUDConfigure a 24dB per octave filter for the 250 Watt System rated @ 4 ohms SY S T E M DI A G R A M STotal Power Delivery RMS Total Power Delivery RMS 500 Watt System rated @ 4 ohms450 Watts 750 Watt System rated @ 4 ohmsTotal Power Delivery RMS TweetersWatts 1000 Watt System rated @ 4 ohmsTotal Power Delivery RMS TweetersNOISE ROCKFORD FOSGATE ACCESSORIESBalanced Line Transmitter FG-BLT Channel B monitors right channel Punch Status Display FG-PSDPunch Status Display connected to one Channel A monitors left channel1.0cap punchEnergy Storage Capacitors XCard CrossoversRemedy SymptomTR O U B L E S H O O T I N G DiagnosisSpeaker Output Low SymptomDiagnosis RemedyLow or distorted output from SymptomDiagnosis RemedyNoise Overview QUICK CHECK FOR TROUBLESHOOTING CAR AUDIO SYSTEMSAUTOSOUND 2000s PrefaceSummation Time for ProcessorsMusic DY N A M I C PO W E R ME A S U R E M E N T SAbout the Dynamic Power Measurements What is an Amplifier?450 Watts 250.2 SP E C I F I C AT I O N SSpecifications subject to change without notice 180Watts 310Watts 620Watts 125Watts 225Watts1000 Watts 250.1 SP E C I F I C AT I O N SSpecifications subject to change without notice 420Watts 710Watts 1420 Watts 250Watts 500 WattsWhat is Not Covered LIMITED WA R R A N T Y IN F O R M AT I O NLength of Warranty What is CoveredN F O R M A T I O N Habitáculo INTRODUCCIÓNUBICACIÓN DE LOS AMPLIFICADORES MaleteroOperación mono/estéreo Montage dans le coffre InstallationINTRODUCTION MONTAGEPage Im Fahrzeugkofferraum EINLEITUNGEINBAUORT DEUTSCHStereo/Mono Betrieb Linken Phasen Schalter auf 0 stellenITALIANO InstallazioneINTRODUZIONE DOVE POSIZIONARLOFase sinistra dellinterruttore posizionata su Stereo/Mono OperationMADE IN THE USA
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