Halo by Parasound® 5 Channel Power Amplifier

Model #: A 52+

• 180 watts RMS x 5 @ 8 O
• 255 watts RMS x 5 @ 4 O
• 225 watts RMS x 2 @ 8 O
• 350 watts RMS x 2 @ 4 O
• Class A/AB circuitry designed by legendary John Curl
• Direct coupled - no capacitors or inductors in audio path ensures the cleanest signal
• Balanced XLR inputs with discrete circuits
• Full power is rated all the way down to 5Hz for unrestricted low-end bass
• Custom 1.5 kVA encapsulated toroid power transformer with independent secondary windings for each channel
• Hand-matched JFETs for input stage
• Hand-matched MOSFETs for driver stage
• Beta-matched 15 amp, 60 MHz bipolar output transistors (3 pairs per channel)
• 100,000 µF power supply filter capacitance
• DC Servo and relay protection circuits
• Auto turn on by audio signal or 12V trigger
• Heavy-duty 24k gold-plated, 5-way speaker terminals
• 3U chassis with updated cosmetics, rack mountable with HRA3 (sold separately)

Power Output - All 5 Channels Driven

• 180 watts x 5, 8 O
• 255 watts x 5, 4 O

Power Output - 2 Channels Driven

• 225 watts x 2, 8 O
• 350 watts x 2, 4 O

Power measurements parameters

• (with 120VAC, 0.05% THD, RMS continuous power, full audio band): 20 Hz - 20 kHz

Current Capacity

• 45 amperes peak, per channel

Dynamic Headroom

• >1.5dB

Slew Rate

• > 130 volts per microsecond

Frequency Response

• 5 Hz - 100 kHz, +0/-3 dB
• 20 Hz - 20 kHz, +0/-0.3 dB

Total Harmonic Distortion (THD)

• < 0.05 % at full power
• < 0.03 % at typical listening levels

IM Distortion

• < 0.04 %

TIM

• Unmeasurable

Interchannel Crosstalk

• > 78 dB at 1 kHz
• > 63 dB at 20 kHz

Input Impedance

• Unbalanced: 47 kO
• Balanced: 94 kO, 47 kO per leg

Input Sensitivity for 28.28 V Output into 8 O

• Unbalanced: 1 V
• Balanced: 1 V per leg
• Total Gain: 29 dB

S/N Ratio

• > 112 dB, input shorted, IHF A-weighted
• > 102 dB, input shorted, unweighted

Damping Factor

• > 1100 at 20 Hz

DC Trigger Requirements

• +9 Vdc to +12 Vdc, 5 mA

Audio Trigger Requirements

• 2 mV - 10 mV

XLR Pin Identification

• 1 = Ground (Shield)
• 2 = Positive
• 3 = Negative (Return)

Power Requirement

• Standby: 1 Watt
• Idle: 125 Watts
• Maximum: 1500 Watts

Dimensions

• Depth without cables: 20”
• Height without feet: 5.25”

Useful Documents