QSC ISA750 450W @ 8 Ohms Power Amplifier

Designed as a cost-effective solution specifically for sound contractors, the ISA Series features seven models including four low impedance models (ISA 280, ISA 450, ISA 750) rated for 2-ohm operation, and three "Ti" versions with isolated 25, 70 and 100 volt outputs for distributed audio systems (ISA 300Ti, ISA 500Ti, ISA 800Ti). Versatile loading options and a comprehensive feature set make the ISA Series a rugged, cost-effective power solution for any permanently installed sound system.

Unique among distributed sound power amplifiers, the "Ti" versions will drive 8- or 4-ohm loads and a distributed system on the same channel simultaneously. This enables a contractor to reduce the number of required amplifier channels by allowing a limited number of distributed speakers to be attached to the same amp as is powering the main sound system.

Housed in a rugged 3-U chassis, all seven models feature rear panel gain controls for tamper resistant operation with 2 dB detents for quick and repeatable settings. Inputs include both XLR and detachable Euro-style connectors. Outputs feature covered barrier strip connectors for safety agency compliance, and for added versatility, a DataPort V2 (Version 2) terminated with an HD-15 connector is provided for use with DPV2-compatible signal processing accessories such as the XC-3 Crossover, SF-3 Subwoofer Filter, LF-3 Low Frequency Filter and the DSP-3 with external power supply.

Selectable high-pass filters are included to protect speakers and prevent speaker transformer saturation with minimal effect on program material. The ISA Series provide additional protection circuitry including DC, infrasonic, thermal overload, RF and short circuit protection.

On the ISA 750 and ISA 800Ti, class H complementary bipolar output circuitry increases system efficiency by reducing AC power draw and waste heat by 40%. Cooling is accomplished via an automatic variable speed fan, which pulls air from back to front.

Features:

• Four models for low-impedance applications
• Three "Ti" versions include low-impedance and isolated 25, 70, and 100 volt outputs for distributed audio systems
• Rear panel gain controls for tamper resistant operation with 2 dB detents for quick and repeatable settings
• XLR and detachable Euro style input connectors
• DataPort V2 for use with DPV2-compatible signal processing accessories (XC-3, SF-3, LF-3) and DSP-3/DSP-4 (with external power supply)
• Independent defeatable clip limiters for reduced distortion
• Selectable high-pass filters protect speakers and prevent speaker transformer saturation with minimal effect on program material (30 Hz or 70 Hz on non-"Ti" models, 50 Hz or 75 Hz on "Ti" models)
• Front panel indicators include power, signal, and clip
• Covered barrier strip output connectors for safety agency compliance
• Automatic variable-speed fan for quiet normal operation with maximum cooling on demand
• Rear-to-front air flow keeps equipment racks cool
• Stereo, Bridge, or Parallel operating modes
• Comprehensive protection circuitry including DC, infrasonic, thermal overload and short circuit protection
• 3-year warranty plus optional 3-year extended service contract

Specifications:

• 8 ohms 20Hz-20kHz 0.1% THD: 450W
• 4 ohms 20Hz-20kHz 0.1% THD: 650W
• 2 ohms 1kHz 1% THD: 1200W
• Bridged Mono 8 ohms 1kHz 0.1% THD: 1500W
• Bridged Mono 4 ohms 1kHz 1% THD: 2400W
• 140V or 200V 50 Hz-16kHz 0.5% THD: 1600W
• Signal to Noise (20Hz-20kHz): 100 dB
• Distortion (SMPTE-IM): < 0.02%
• Input Sensitivity @ 8 ohms: 1.07v (+2.8 dBu)
• Voltage Gain @ 8 ohms: 56.2x (35 dB)
• Output Circuitry: Class H
• Distortion (Typical):
      * 20 Hz-20 kHz: 10 dB below rated power: Less than 0.03% THD, 4 ohms and 8 ohms
      * 1.0 kHz and below: full rated power: Less than 0.03% THD, 4 ohms and 8 ohms
• Frequency Response, 10dB below rated output power: 20Hz-20kHz, +0/-1dB, -3 dB points: 5 Hz + 50 Hz
• Damping Factor (Direct Outputs): > 250 @ 8 ohms
• Output Regulation: < 1.5 dB
• Input Impedance: 10 k ohms unbalanced, 20 k ohms balanced
• Input Clipping: 10 Vrms (+22 dBu)
• Cooling: Continuously variable speed fan, back-to-front air flow
• Connectors, each channel:
      * Input: Active balanced; 3-pin Euro-style detachable terminal block and XLR (pin 2+)
      * Output: Covered barrier strips
      * DataPort V2: HD-15 connector
• Controls:
      * Front: AC switch
      * Rear: Ch. 1 and Ch. 2 gain knobs, 10-position DIP switch
• Indicators: PWR-ON Green LED, SIGNAL Green LED (1 per channel), CLIP Red LED (1 per channel)
• Amplifier Protection: Full short circuit, open circuit, thermal, ultrasonic, and RF protection; Stable into reactive or mismatched loads
• Power Requirements: 120, 230, VAC, 50-60 Hz
• Load Protection: On/off muting; Triac crowbar: ISA 750
• Rack-mount size: 3 RU
• Dimensions: 19" x 5.25" x 15.9" (48.3 x 13.3 x 40 cm)
• Weight: 47 lbs. (21.3 kg)