Parasound A21+

Product Highlights:

• Power Output:

  • 300 watts x 2 channels at 8 ohms (RMS, both channels driven)
  • 500 watts x 2 channels at 4 ohms (RMS, both channels driven)
  • 1000 watts x 1 channel at 8 ohms in bridged mode
  • Power is measured at 120 VAC with 0.1% THD, RMS continuous power across the full audio band (20 Hz - 20 kHz)

• Circuit Design:

  • Designed by legendary audio engineer John Curl for superior sound quality
  • High bias Class A/AB operation ensures optimal performance across a wide range of listening levels
  • Direct-coupled signal path with no capacitors or inductors for the cleanest audio output

• Current and Stability:

  • Delivers 60 amperes of peak current per channel, providing ample power for demanding speakers
  • Stable operation with speaker impedance dips as low as 1.5 ohms, making it compatible with a wide range of speakers

• Inputs and Connectivity:

  • Balanced inputs with discrete circuits for pristine signal transmission
  • Gold-plated RCA input and loop output jacks for high-quality connections
  • CHK Infinium custom 5-way speaker binding posts for secure and flexible speaker connections

• Power Supply and Components:

  • 1.3 kVA shielded toroid transformer with independent windings for each channel
  • Independent power supplies for input, driver, and output stages to minimize interference and ensure consistent power delivery
  • 108,000 µF filter capacitors for the output stages provide stable and clean power

• Advanced Protection and Convenience:

  • DC Servo and relay protection circuits safeguard your system from faults
  • AC turn-on inrush surge protection with relay bypass prevents power surges during startup
  • Harris hyper-fast soft-recovery bridge diode rectifiers for efficient and reliable power management
  • Automatic turn-on via 12V trigger or audio sensing for seamless integration into your home audio setup

• Build and Design:

  • Housed in a 4U rack space chassis with rear carry handles for easy installation and handling
  • Rack mount hardware is included, making it easy to integrate into professional setups

• Specifications:

  • Slew Rate: Greater than 130 volts per microsecond for quick response to audio signals
  • Frequency Response: 5 Hz - 100 kHz, +0/-3 dB; 20 Hz - 20 kHz, +0/-0.25 dB for detailed and accurate sound reproduction
  • Total Harmonic Distortion (THD): Less than 0.1% at full power, less than 0.03% at typical listening levels
  • Intermodulation (IM) Distortion: Less than 0.04%
  • Transient Intermodulation Distortion (TIM): Unmeasurable for the clearest audio output
  • Inter-channel Crosstalk: Greater than 80 dB at 1 kHz, greater than 70 dB at 20 kHz for excellent channel separation

• Input and Output:

  • Input Impedance: Unbalanced: 33k ohms; Balanced: 66k ohms (33k ohms per leg)
  • Input Sensitivity for 28.28V Output into 8 ohms: Unbalanced: 1V; Balanced: 1V per leg
  • Total Gain: 29 dB
  • Damping Factor: Greater than 1100 at 20 Hz for tight control over speaker movement
  • XLR Pin Identification: 1 = Ground (Shield), 2 = Positive, 3 = Negative (Return)

• Trigger Requirements:

  • DC Trigger: +9 VDC to +12 VDC, 5 mA
  • Audio Trigger: 2 mV - 10 mV

• Dimensions:

  • Width: 17-5/8" (448 mm)
  • Height without feet: 7-1/8" (181 mm)
  • Height with feet: 7-3/4" (197 mm)
  • Depth: 20" (508 mm); Depth with cables: 21-1/2" (546 mm)

• Weight:

  • Net Weight: 71 lb. (32.2 kg)
  • Shipping Weight: 88 lb. (39.9 kg)

• Power Requirements:

  • Standby: 1 watt
  • Idle (no music playing): 160 watts
  • Typical Listening Levels: 300 watts
  • Maximum Power Consumption: 1400 watts