Every Part is Chosen for Accuracy & Reliability

Every part used in the A 52+ is carefully chosen for its accuracy and reliability. Metal film resistors with 1% tolerance are selected for their precision and because their values don't drift as they heat up during operation. Polypropylene and mica capacitors are used extensively for their superior linearity and low dielectric absorption. Semiconductors are selected for superior performance in their specific roles in the circuit. Gold has the best conductivity of any metal, so we use high quality gold-plated input connectors and speaker terminals.

The double-sided circuit boards are FR4 glass epoxy for long-term durability. The chassis is made of heavy gauge steel to safely house the internal circuitry. This attention to detail when selecting parts makes the difference between a very good amplifier and an outstanding amplifier.

Highly Efficient & Quiet Power Supply

The heart of the Halo A 52+ power supply is a 1.5 kVA toroid power transformer, chosen for its efficiency, low hum field, and high power rating. Encapsulating this massive power transformer in an epoxy-filled steel canister assures ultra-quiet performance.

The A 52+ power transformer employs multiple independent secondary windings, so that each amplifier channel has its own power supply, assuring more than ample DC voltage at all times and under all conditions. It also reduces inter-channel crosstalk that can blur the sound and impair the correct sense of where instruments, dialogue and effects are positioned.

Each channel's +/- 80 Vdc B+ and B- supply rails use high-speed rectifier diodes and two Rubycon custom-made 10,000uF electrolytic filter capacitors, chosen for their low Equivalent Series Resistance (ESR), dielectric absorption and resistance to high temperature. In addition, these filter capacitors are bypassed with smaller polypropylene capacitors to reduce AC ripple in the DC supply and to further eliminate noise and interference that is generated in AC power lines from computers and other appliances in the home.

Features

- 180 watts RMS x 5 @ 8 Ω

- 255 watts RMS x 5 @ 4 Ω

- 225 watts RMS x 2 @ 8 Ω

- 350 watts RMS x 2 @ 4 Ω

- 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)

Parasound A52+ Halo Amplifier User's Manual

Specifications

Power Output - All 5 Channels Driven 
180 watts x 5, 8 Ω 
255 watts x 5, 4 Ω

Power Output - 2 Channels Driven 
225 watts x 2, 8 Ω 
350 watts x 2, 4 Ω

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 kΩ 
Balanced: 94 kΩ, 47 kΩ per leg

Input Sensitivity for 28.28 V Output into 8 Ω 
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)

Dimensions 
Width: 17^1/4" 
Height without feet: 5^1/4" 
Height with feet: 5^7/8" 
Depth: 20" (508 mm) 
Depth with cables: 21^1/4" 

Net Weight: 55 lbs

Shipping Weight: 69 lbs

Power Requirement 
Standby: 1 Watt 
Idle: 125 Watts 
Maximum: 1500 Watts

Contact us to inquire how you can finance your purchase through our partner, .