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WHAT ELSE DISTINGUISHES THESE AMPLIFIERS?

Constant power into varying impedances. It takes twice as much current to develop a given wattage into 2

as it does into

8

—but only half the voltage. Many amplifiers quote a high output current at 2

but have an unpublished operating time

measured in a handful of seconds—before thermal shutdown (hopefully) precludes thermal meltdown.

Our solution for this is selectable rail voltages for optimizing the amplifier to the load. This is impractical for conventional
line-frequency supplies—and it comes at a cost for switching supplies. A full PWM design is needed, adding a coupled out-
put inductor, a current-sense transformer and a current-mode controller IC. An  impedance selector switch is also needed
for each channel, simultaneously altering the rail voltage and the current limit. Each channel of the amplifier can be inde-
pendently optimized for 2

, 4

, and 8

, useful in bi-amping and tri-amping, etc. Both 70 and 100 volt constant voltage

line operation are possible. Instructions on the back of the amplifier explain the various options.

UNIVERSAL LINE VOLTAGE INPUT

Voltage selection is provided in two bands: 100-140 volts and 200-265 volts, (both 50-60 Hz) via two quick-connect termi-
nals located on the EMI filter board, accessed by removing the top cover. The current-mode control system automatically
corrects for the bulk of power line variation with each band. This allows most of the PWM action to be reserved for pro-
gramming and regulation of output voltages. A flyback topology provides the numerous housekeeping low voltages required
by various circuits.

PROTECTION CIRCUITS

Fan control circuit - Each amplifier channel has a fan control circuit that measures the temperature of the heatsink, and
adjusts the fan speed accordingly. This thermally-tracking fan speed circuit keeps fan noise to a minimum when power
demands are low. Typically the fans will be turning slowly even at idle conditions - although abnormally low room temper-
atures may allow the fans to turn off completely. The fan control circuit also has a turn-on blast feature that runs the fans at
full speed for a few seconds every time the amplifier is turned on. This serves the dual function of cleaning out the air tun-
nel, and providing a simple means to check the fans for proper operation. If you suspect that the fans are not operating cor-
rectly, try turning the amplifier off, then listening or feeling for the turn-on blast when the amplifier is turned back on.

Thermal Standby - If excessive heatsink temperature is detected, the individual amplifier channel will go into thermal stand-
by mode. The amplifier will be turned off, and the THERMAL LED illuminates until heatsink temperatures return to normal.
At that time the amplifier automatically turns back on, and continues operating normally.

NOMAD protection - The amplifier output MOSFETs are protected from excessive power dissipation by NOMAD protec-
tion circuitry. NOMAD (Non-Multiplying Advance Decision) limits the power when it measures signal voltage and current
conditions that will exceed the pre-determined power limit of the MOSFETs. This instantaneous power calculation is per-
formed on each output MOSFET, causing the amplifier to automatically limit power when needed. In this way, a speaker
load with an impedance “dip” over a particular frequency range will only activate the NOMAD protection when sufficient
audio is present at that same frequency range, but continue operating normally otherwise.

Short protection - The NOMAD protection circuit also protects against shorts, and will instantly limit the output power if
speaker wires are shorted together. Normal operation will continue immediately after the short is removed.

Power Supply Current Limiting protection- The switching power supply will protect itself from excessive power dissipation
by continuously monitoring currents in the switching MOSFETs. The Current Limiting circuit measures the currents in the
switching MOSFETs and will instantly limit them to a safe level.

Soft turn-on/fast turn-off - Speaker loads are protected from turn-on/turn-off transients by a circuit that monitors the power
supply, and controls the amplifier when power on/off events are detected. At turn-on, this circuit waits for power supply
voltages to settle, then sends a turn-on ramp signal to slowly turn the amplifier on. At turn-off, this circuit acts quickly to
turn off the amplifier before power supply capacitors discharge, and voltages collapse into the output signal - causing
speaker “pops”.

Summary of Contents for SR2300

Page 1: ...Owner s Manual Owner s Manual SR2300 SR2600 SR2300 SR2600...

Page 2: ......

Page 3: ...Output 13 Power Switch 13 OPERATION 14 Input 14 Daisy Chain Output 14 Earth Grounded Equipment 14 Floated Equipment 15 Level Controls 15 Biamp Stereo Switch 16 Stereo Mono 70V 100V Switch 16 Protect 1...

Page 4: ...y Manufacturer s Name Hafler Manufacturer s Address 546 South Rockford Drive Tempe Arizona 85281 Importer s Name Importer s Address Type of Equipment 2 channel Audio Power Amplifier Model No SR2300CE...

Page 5: ...receptacle Never remove the round grounding pin on the plug in an attempt to mate to a two wire ungrounded receptacle use a grounding adapter with the grounding tab or wire suitably connected to eart...

Page 6: ...esto no ocurra como podr a suceder debajo de una alfombra o al pasar el cable por una esquina aguda etc 10 ATERRAMIENTO DEL CABLE DE CORRIENTE El cable de corriente es del tipo aterrado de tres hilos...

Page 7: ...e Verl ngerungskable 11 ZEITR UME IN DENE DAS GER T NICHT GENUTZT WIRD Wird das Ger t ber einen l ngeren Zeitraum nicht genutzt z B Urlaub ziehen Sie bitten den Netzstecker aus der Steckdose 12 REINIG...

Page 8: ...tionement sans risque de tout mat riel reli 11 P RIODES DE NON UTILISATON Durant les p riodes de non utilisation la prise de courant ne devrait pas tre branch e une source d energie 12 NETTOYAGE Le ma...

Page 9: ...arati connessi E alters importante che vengano sempre impiegate prolunghe con la configurazaione a tre fili con terra 11 PERIODI DI NON UTILIZZO Durante lunghi periodi di non utilizzo staccare il cavo...

Page 10: ...ANCE 47k per phase balanced 47k per phase balanced DAMPING FACTOR 500 500 POWER THERMAL REQUIREMENTS Idle Condition 55W 70W U version 860mA 115VAC 1 0A 115VAC CE version 430mA 230VAC 500mA 230VAC Ther...

Page 11: ...g an amplifier of outstanding audio qualities high effi ciency and unprecedented value TRANS nova Class G is that answer The most common high efficiency Class H methods raise the rail voltages going t...

Page 12: ...plifier is turned on This serves the dual function of cleaning out the air tun nel and providing a simple means to check the fans for proper operation If you suspect that the fans are not operating co...

Page 13: ...spade lugs or dual banana plugs to be connected to the amplifier 11 Internal Fans internal fans keep the amplifier circuitry cool Allow a minimum of 3 clearance on the front and back of the amplifier...

Page 14: ...ve included AC mains current draw and thermal dissipation values in the Specifications Sheet The specifications listed are for idle no sig nal 1 8th power normal operating conditions for continuous vo...

Page 15: ...ted to the Chassis and AC mains earth ground This connection is made through a 0 resistor R350 located on the input board The resistor serves as a fuselink in the case of severe system faults To check...

Page 16: ...output ground connected to the earth grounded chassis This can be verified with an ohmmeter by disconnecting the mains power cord from the AC outlet and checking for continuity between the earth groun...

Page 17: ...through of all 3 pins of the input jack LEVEL CONTROLS The gain for each channel can be controlled individually using the front panel level control The controls have 32 detented positions that are cal...

Page 18: ...o mode also use the CH B input connector and level control only The 70V or 100V speaker array load should be connected across the red terminals of the output connectors Set both load switches to the a...

Page 19: ...level control all the way OFF If the clipping continues then the signal is clipping at the amplifier input Input clipping occurs at 3Vrms sine and can be eliminated by attenuating the signal before it...

Page 20: ...input Load across RED terminals Set load switches to one half load impedance A Division of Rockford Corp Tempe AZ 85281 Made in the U S A S R 2 3 0 0 300 W Stereo 2 8 600W Mono 70V 100V Mono 250W 100...

Page 21: ...0 Volt Transformer 70 Volt Transformer Parallel Array etc 100V 70V 100V 70V SR2300 SR2600 1 Connect signal from source to CH B input 2 Biamp Stereo switch not active Stereo Mono switch overrides this...

Page 22: ...d rating of fuse 4 16 100 Volt Transformer 100 Volt Transformer Parallel Array etc 100V 70V 100V 70V SR2300 SR2600 Power 70V 4 Load 2 100V 8 70V 4 2 100V 8 BIAMP STEREO CH A IN 300W 2 8 Mono 70V 100V...

Page 23: ...roduct purchased outside the United States please contact your local dealer 4 Shipping charges to get the unit to Hafler 5 Any product which has had the serial number defaced altered or removed Limit...

Page 24: ...R150 R160 R147 R146 R145 R142 R139 R138 R137 R119 R135 R131 R129 R120 R118 R132 R121 CR53 CR52 CR29 CR24 C60 C59 C58 C57 JW6A1 16 1 C124 C133 U14 U13 SW3 SW2 R295 R293 R290 R283 R294 R288 C128 C130 R...

Page 25: ...23 J9 J10 J16 J3 J5 J1 C5 C3 C2 R2 L2 L1 L3 C6 C1 C4 R3 C7 R1 J12 J11 R4 J8 J15 J13 J7 J6 J14 DANGER HIGH VOLTAGE 230V 230V 120V 120V ORG ORG WHT WHT BLACK BLACK KS4R PC 2460 E HAFLER J4 J2 EMI FILTER...

Page 26: ...24 Schematic Diagrams PC 2460 e sch 1 EMI FILTER...

Page 27: ...25 C600_maualB sch 4 BRIDGE RECTIFIER...

Page 28: ...26 AMPLIFIER...

Page 29: ...27 C600_maualB sch 1...

Page 30: ...28 PROTECTION...

Page 31: ...C600_maualB sch 2 29...

Page 32: ...30 HIGH VOLTAGE CONTROL...

Page 33: ...31 C600_maualB sch 3...

Page 34: ...32 HOUSEKEEPING CONTROL...

Page 35: ...33 C600_maualB sch 6...

Page 36: ...34 INPUT...

Page 37: ...35 C600_maualB sch 8...

Page 38: ...36 POWER...

Page 39: ...37 C600_maualB sch 5...

Page 40: ...IVISION OF ROCKFORD CORPORATION 546 SOUTH ROCKFORD DRIVE TEMPE ARIZONA 85281 U S A IN U S A 480 967 3565 IN CANADA 604 942 1001 IN EUROPE FAX 8503 9340 14 IN JAPAN FAX 81 559 79 01265 MAN 2568C 5 00 M...

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