Parasound Halo A 52 - 5-Channel Power Amplifier - THX Ultra2 Certification

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All channels tested clean... to 170W at 8 ohms when it's officially rated for 125W!

Check out our internal photo and you'll see how that was possible.

They should have built a top with a window to properly show off this design and build.

Light scratches on the sides of the chassis as shown in our photos, as well some damage to the front "P" raised logo letter. 

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
• 20 beta-matched 15 amp, 60 MHz bipolar output transistors
• 1.4 kVA encapsulated toroid power transformer with independent secondary windings for each channel
• 100,000 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, 12v trigger out
• 3U Chassis with carry handles - rack mountable with HRA3 (sold separately)

Parasound Halo A 52 Manual

Specifications:
Continuous power output:
125 watts RMS x 5, 20 Hz - 20 kHz, 8 Ω, all channels driven
225 watts RMS x 5, 20 Hz - 20 kHz, 4 Ω, all channels driven

Current capacity:
30 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 Level

Input impedance:
47 k Ω unbalanced; 94 k Ω balanced

S/N ratio:
113 dB, input shorted, IHF A-weighted

Damping factor:
> 1000 at 20 Hz

Voltage:
110V - 120V

Dimensions:
17-1/4" W x 5-7/8" H x 19-3/4 " D - (5-1/4 " H without feet)

Net weight:
50 lb.

The SkyFi Testing Process for Solid State Amplifiers:

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage.

We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Finally, we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. If there is an issue, it will usually be noticeable at this point. If everything reads clean, we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. The amplifier then remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If there are balanced inputs available they will be also be tested.

Final testing involves pushing actual music thorough the amplifier. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. Our test bench has reference vintage KEF speakers that we're very familiar with which quickly reveal any discrepancies. Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.