QSC RMX850A Power Amplifier

The 300 watts per channel 4Ω QSC RMX850a Power Amplifier is a 2RU rack mountable amplifier designed for live sound reinforcement applications. The amplifier features two Class AB output channels that can operate in either stereo or mono bridge mode. The unit operates on a standard 15 amp plug and utilizes high-current toroidal transformers for less noise and better performance when pushing a 2 ohm load. To reduce distortion, the amplifier utilizes independent user-defeatable clip limiters and includes LED indicator lights to show the presence of the signal and when the signal is clipping. 

The chassis of the amplifier is designed with front to rear cooling vents and includes selectable low-frequency filters at 30 Hz and 50 Hz to protect speakers from bottoming out and improve headroom when driving mid and high frequencies. The front panel of the unit features two gain control knobs for easy access and each channel is protected by a dedicated DC and thermal overload protection circuit. For inputs, the back of the unit accepts both balanced 1/4" and XLR inputs. For outputs, the unit features both Neutrik Speakon and touch-proof binding post connections.

• Power Rating: Stereo mode (both channels driven) 
• 8 Ω FTC 20 to 20,000 Hz at 0.1% THD: 185 W 
• 8 Ω EIA 1,000 Hz at 0.1% THD: 200 W 
• 4 Ω FTC 20 to 20,000 Hz at 0.1% THD: 280 W 
• 4 Ω EIA 1,000 Hz at 0.1% THD: 300 W 
• 2 Ω EIA 1,000 Hz at 0.1% THD: 430 W 
• Bridge-mono mode 8 Ω FTC 20 to 20,000 Hz at 0.1% THD: 530 W
• Bridge-mono mode 8 Ω EIA 1,000 Hz at 0.1% THD: 600 W 
• Bridge-mono mode 4 Ω EIA 1,000 Hz at 0.1% THD: 830 W
• Signal-to-Noise Ratio: > -100 dB
• Distortion:
  • SMPTE-IM: < 0.01% 
  • For 8 and 4 Ω load 
• THD for 20 to 20,000 Hz at 10 dB below rated power: less than 0.03% 
• THD for 1,000 Hz at full rated power: less than 0.03%
• Input Sensitivity: 1.15 V (+3.4 dBU) at 8 Ω
• Voltage Gain: 31.6x (30 dB)
• Circuit Type: Class AB
• Power Consumption: 4.5 A 
• 1/8 power pink noise at 4: Ω 6.6 A
• Damping Factor: > 300 at 8Ω
• Input Impedance:
  • 10 kΩ balanced 
  • 20 kΩ unbalanced
• Frequency Response:
  • 20 to 20,000 Hz +0/-1 dB -3 dB points 
  • 5 Hz to 50,000 Hz (LF filter bypassed/8 Ω)
• Input Connections:
  • Active balanced 3-pin Euro-style detachable terminal block 
  • 2 x 3-pin XLR 
  • 2 x 1/4" TRS
• Cooling: Continuously variable speed fan, back-to-front airflow
• Output Connectors: Touch-proof binding posts 
• 2 x Neutrik Speakon
• Controls Front Panel:
  • C switch 
  • Channel 1 gain knob 
  • Channel 2 gain knob
• Controls Rear Panel: 10-position DIP switch
• Indicators: Power-on: green LED 
• Signal: yellow LED (1 per channel) 
• Clip: red LED (1 per channel) 
• Protect: red LED (1 per channel)
• Power Requirements: 100, 120, 230 VAC at 50 to 60 Hz (factory configured)

Protection 

• Amplifier: Full short circuit, open circuit, thermal, ultrasonic, RF protection. Stable into reactive or mismatched loads 
• Load: Turn-on/off muting/AC coupling (850, 1450)/ Triac Crowbar (1050HD, 2450, 4050HD, 5050) on each channel
• Rack Spaces2
• Plug Type:
• 100/120V: NEMA 5-15 
• 230V: CEE7/7

• Dimensions: (H x W x D)3.5 x 19.0 x 15.9" (89.0 x 482 x 404 mm)
• Weight: 35.0 lb (15.9 kg)