The HALO A51 is a thoroughbred THX Ultra2 certified, high bias Class A/AB amplifier that gives you the optimal amount of performance that only most really high end systems achieve, again nailing Parasound's colours to the mast when it comes to that getting the maximum 'bang for your buck'.

Specifications and Features:

• Circuitry designed by legendary John Curl
• THX Ultra2 certified
• High bias Class A/AB operation
• Balanced inputs with discrete circuits and XLR connectors
• Direct Coupled - no capacitors or inductors in signal path
• Complementary MOSFET driver stage and JFET input stage
• 40 beta-matched 15 amp, 60 MHz bipolar output transistors
• 2.2 kVA encapsulated toroid power transformer with independent
    secondary windings for each channel
• 164,000 μF power supply filter capacitance
• DC Servo and relay protection circuits
• AC present, channel status, high temperature indicators
• Heavy-duty 24k gold-plated 5-way speaker terminals
• Gold-plated RCA input jacks; ground lift switch
• Auto turn-on by 12v trigger or audio signal
• Continuous power output:
  250 watts RMS x 5, 20 Hz - 20 kHz, 8 Ω, all channels driven
  400 watts RMS x 5, 20 Hz - 20 kHz, 4 Ω, all channels driven
  
• Current capacity: 60 amperes peak per channel
• Power bandwidth: 5 Hz - 100 kHz, +0/-3 dB at 1 watt
• Total harmonic distortion: < 0.2 % at full power
• IM distortion: balanced 16 V rms < 0.04 %
• Slew rate: > 130 V/µsecond
• Dynamic headroom: > 1.5 dB
• Interchannel crosstalk:
  > 78 dB at 1 kHz;
  > 63 dB at 20 kHz
• Input sensitivity: 1 V for 28.28 V (THX Reference)
• Input impedance: 47 k Ω unbalanced; 94 k Ω balanced
• S/N ratio: 112 dB, input shorted, IHF A-weighted
• Damping factor: > 1100 at 20 Hz
• Dimensions: 17-1/2" w x 7-5/8" h x 20" d, 7" h without feet