Rockford Fosgate 250.1 Technical Design Features, TOPAZ Tracking Operation Pre-AmplifierZone

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TECHNICAL DESIGN FEATURES

TECHNICAL DESIGN FEATURES

Many of the solutions to common design problems encountered by Rockford Fosgate engineers created entire new circuit designs as well as new ways to construct the Punch 250.2 and 250.1 Power Amplifiers. In our flagship amplifiers, no expense was spared in design and construction from the unique circuitry design to the manufacturing process that has proven to be the industry reference for many years. Described below are just some of the accomplishments achieved by our engineering and manufacturing staff.

◆trans•nova (TRANSconductance NOdal Voltage Amplifier)

The trans•nova (TRANS conductance NOdal Voltage Amplifier) is a patented circuit (U.S. Patent 4,467,288) that allows the audio signal to pass through the amplifier at low voltage. Each amplifier channel utilizes its own “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.

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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 output stage is further refined into a trans-impedance stage (current to voltage converter) to achieve a short loop (fast) negative feedback. The output stage is driven cooperatively by a transconductance stage (voltage to current converter).

THE RESULT: Superior sound quality, greater efficiency and higher reliability.

◆DIABLO (Dynamically Invariant A-B Linear Operation)

DIABLO (Dynamically Invariant A-B Linear 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 MOSFETs cause a high capacitive load on the driver stage. This load can make the high frequencies sound harsh. 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 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 20-100 times better than amplifiers without TOPAZ.

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

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Contents power powerpower 250.1PRACTICE 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 SPunch Power Punch PowerINTRODUCTION TO 250 SERIES DIABLO Dynamically Invariant A-BLinear Operation TECHNICAL DESIGN FEATURESTOPAZ Tracking Operation Pre-AmplifierZone trans nova circuitryXCard Internal Crossover Stereo Pass-ThruDSM Discrete Surface Mount Technology ITS Increased Thermal Stability Balanced Line InputsNOMAD NOn-MultiplyingAdvanced Decision 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 CONSIDERATIONSTrunk Mounting BATTERY AND CHARGINGPassenger Compartment Mounting Engine Compartment MountingW I R I N G T H E S Y S T E M USING PASSIVE CROSSOVERS 6 dB/Octave High-Pass TABLE OF CROSSOVER COMPONENT VALUES6 dB/Octave Low-Pass FreqCU S T O M I Z I N G T H E XCA R D US I N G T H E XCARDHigh-Pass Low-PassButterworth Alignment Q = XCA R D RESISTOR CHART1% resistors used with 0.047∝ F capacitors Butterworth Alignment Q =250.2 Power Connections Option #2 250.2 INSTALLATION250.2 Power Connections Option #1 Stereo/Mono Operation Stereo OperationLeft Phase Switch set to Right Phase Switch set toEZ-BridgedOperation Bridged OperationLeft Phase Switch set to Right Phase Switch set toPage XCard not required Pass-Thru uses output from XCard 250.2 uses output from XCardPage Configurea24dBperoctave and“AudiophileBypass”the Configurea12dBperfilterfor Pass-ThruConnecting the BLT USING THE 250.2 BALANCED LINE INPUTS8.0 VAC Level Setting the BLTPerformance Characteristics Disconnect Speakers from the250.1 Power Connections Option #2 250.1 INSTALLATION250.1 Power Connections Option #1 minimum Mono OperationPhase Switch set to orFullRange AmplifiersPowerImpedanceforbridgedchannelshouldbe4Ω minimum Stereo/Mono OperationImpedanceforeachstereochannelshouldbe2Ω minimum minimum Bridged Mono OperationImpedanceforbridgedchannelshouldbe4Ω Pass,-High -LoworPass RangeFull“Audiophile Bypass” the U S I N G T H E 250.1 SIGNALS W I T C H I N G N E T W O R K XCard Configure a 12dB per octave filter for theLOUD TUNEConfigure a 24dB per octave filter for the Total Power Delivery RMS SY S T E M DI A G R A M S250 Watt System rated @ 4 ohms Total Power Delivery RMS 500 Watt System rated @ 4 ohmsTotal Power Delivery RMS 750 Watt System rated @ 4 ohmsTweeters 450 WattsTotal Power Delivery RMS 1000 Watt System rated @ 4 ohmsTweeters WattsBalanced Line Transmitter FG-BLT ROCKFORD FOSGATE ACCESSORIESNOISE Punch Status Display connected to one Punch Status Display FG-PSDChannel A monitors left channel Channel B monitors right channelEnergy Storage Capacitors punchXCard Crossovers 1.0capTR O U B L E S H O O T I N G SymptomDiagnosis RemedyDiagnosis SymptomRemedy Speaker Output LowDiagnosis SymptomRemedy Low or distorted output fromAUTOSOUND 2000s QUICK CHECK FOR TROUBLESHOOTING CAR AUDIO SYSTEMSPreface Noise OverviewSummation Time for ProcessorsAbout the Dynamic Power Measurements DY N A M I C PO W E R ME A S U R E M E N T SWhat is an Amplifier? MusicSpecifications subject to change without notice 250.2 SP E C I F I C AT I O N S180Watts 310Watts 620Watts 125Watts 225Watts 450 WattsSpecifications subject to change without notice 250.1 SP E C I F I C AT I O N S420Watts 710Watts 1420 Watts 250Watts 500 Watts 1000 WattsLength of Warranty LIMITED WA R R A N T Y IN F O R M AT I O NWhat is Covered What is Not CoveredN F O R M A T I O N UBICACIÓN DE LOS AMPLIFICADORES INTRODUCCIÓNMaletero HabitáculoOperación mono/estéreo INTRODUCTION InstallationMONTAGE Montage dans le coffrePage EINBAUORT EINLEITUNGDEUTSCH Im FahrzeugkofferraumStereo/Mono Betrieb Linken Phasen Schalter auf 0 stellenINTRODUZIONE InstallazioneDOVE POSIZIONARLO ITALIANOFase sinistra dellinterruttore posizionata su Stereo/Mono OperationMADE IN THE USA
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