The ISA300ti Installed System Amplifier are designed to meet the needs of sound system designers and contractors worldwide. Three models feature isolated 25, 70, and 100 volt outputs for distributed sound systems, while four low impedance models are rated for 2 ohm operation. .

ISA300TI Features

  • Low-impedance outputs plus isolated 25, 70, and 100 volt outputs for distributed audio systems
  • Rear panel gain controls for tamper resistance; 2-dB detents allow 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 (50 Hz or 75 Hz) protect speakers and prevent speaker transformer saturation, with minimal effect on program material
  • Front panel indicators include power, signal, and clip
  • Covered barrier strip output connectors for safety agency compliance
  • Automatic on-demand variable-speed fan: quiet normal operation, with maximum cooling when needed
  • Rear-to-front air flow helps keep 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 ISA280 ISA450 ISA750 ISA1350 ISA300Ti ISA500Ti ISA800Ti
  OUTPUT POWER PER CHANNEL, STEREO MODE, both channels driven
8Ω, 20 Hz–20 kHz 0.1% THD 4Ω, 20 Hz–20 kHz 0.1% THD 2Ω 1 kHz 1% THD 185 W 280 W 430 W 260 W 425 W 700 W 450 W 650 W 1200 W 800 W 1300 W 2000 W 185 W 280 W 430 W 260 W 425 W 700 W 450 W 650 W 1200 W
  DIRECT POWER PER CHANNEL, STEREO MODE
70V, 20 Hz–20 kHz +0/-0.3 dB 0.5% THD - - - 1500 W - - -
  TRANSFORMER-ISOLATED OUTPUT POWER PER CHANNEL, STEREO MODE
70V or 100V, 50 Hz–16 kHz 0.5% THD 25V, 50 Hz–16 kHz 0.5% THD - - - - - - - - 300 W 200 W 500 W 300 W 800 W 500 W
  OUTPUT POWER, BRIDGED MONO MODE
8Ω, 1 kHz 0.1% THD 4Ω 1 kHz 1% THD 600 W 830 W 900 W 1400 W 1500 W 2400 W 2800 W 4000 W 600 W 830 W 900 W 1400 W 1500 W 2400 W
  TRANSFORMER-ISOLATED OUTPUT POWER, BRIDGED MONO MODE
140V or 200V, 50 Hz-16 kHz 0.5% THD - - - - 600 W 1000 W 1600 W
Signal to Noise (20 Hz-20 kHz) 100 dB
Distortion (SMPTE-IM) Less than 0.01% Less than 0.01% Less than 0.02% Less than 0.01% Less than 0.01% Less than 0.01% Less than 0.02%
Input Sensitivity @ 8 ohms 1.15 V (+3.4 dBu) 1.07 V (+2.8 dBu) 1.07 V (+2.8 dBu) 1.24 V (+4.1 dBu) 1.15 V (+3.4 dBu) 1.07 V (+2.8 dBu) 1.07 V (+2.8 dBu)
Maximum Voltage Gain 33.4× (30.5 dB) 44.7× (33 dB) 56.2× (35 dB) 64.0× (36.1 dB) 33.4× (30.5 dB) 44.7× (33 dB) 56.2× (35 dB)
Output Circuitry Class AB Class AB Class H, 2 tier Class H, 3 tier Class AB Class AB Class H, 2 tier
THX Approved - Yes Yes - - - -
Weight - Net 36 lb (16.3 kg) 42 lb (19 kg) 47 lb (21.3 kg) 68 lb (30.8 kg) 44 lb (20.0 kg) 49 lb (22.3 kg) 57 lb (26 kg)
Weight - Shipping 42 lb (19.1 kg) 48 lb (22 kg) 53 lb (24.0 kg) 77 lb (34.4 kg) 50 lb (22.7 kg) 55 lb (25 kg) 63 lb (28.6 kg)
  ALL MODELS
Distortion (Typical) 20 Hz–20 kHz: 10 dB below rated power 1.0 kHz and below: full rated power Less than 0.03% THD, 4 ohms and 8 ohms Less than 0.03% THD, 4 ohms and 8 ohms
Frequency Response 10 dB below rated output power ISA 280, 450, 750 and 1350: 20 Hz–20 kHz, +0/-1 dB; -3 dB points: 5 Hz and 50 kHz ISA 300Ti, 500Ti and 800Ti: Direct outputs: -3 dB @ 50 Hz, -0.5 dB @ 20 kHz; XF outputs: 50 Hz–16 kHz, +1/-3 dB
Damping Factor with 8Ω Load (direct outputs) Greater than 200; ISA 1350 greater than 250
Output Regulation (isolated outputs) Less than 1.5 dB
Input Impedance 10 kΩ unbalanced, 20 kΩ balanced
Input Clipping 10 V rms (+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)
Dimensions (HWD) inches 5.25 x 19 x 15.9 / 3RU
Dimensions (HWD) mm 133 x 483 x 400 / 3RU
Amplifier Protection Full short circuit, open circuit, thermal, ultrasonic, and RF protection; Stable into reactive or mismatched loads
Power Requirements 120 or 230 VAC, 50–60 Hz
Load Protection On/off muting; Triac crowbar: ISA 750, 1350, and 800Ti; AC coupling: ISA 280, 300Ti, 450, and 500Ti
List price: $1,085.00
Price: $1,085.00
SKU: ISA300TI
Catalog: 
Commercial Amplifiers
Brand: 
QSC Audio
Dimensions: 24 in × 22 in × 9 in
Weight: 52 lb