A 52+ Five Channel Amplifier OWNER’S GUIDE
Important Safety Instructions The lightning flash with the arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of “dangerous voltage” inside the product that may constitute a risk of electric shock. The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance instructions in the literature accompanying the product. TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER.
Table of Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Placement and Ventilation Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 AC Mains Voltage Rack Mounting Audio Input and Output Connections . Turn On Options . . .
INTRODUCTION Thank You for Choosing Parasound Your new Parasound Halo A 52+ power amplifier has been designed with the most advanced, proven class A/AB amplifier technology. The A 52+ is built to extremely strict quality and performance standards for which Parasound is renowned. We’re proud to offer you this exceptional audio component that will bring you many years of enjoyment and dependability.
Unpacking Your A 52+ & Placement Guidelines Unpacking Your A 52+ Carefully remove your A 52+ from its shipping carton and locate the enclosed accessories: • AC power cord • A 12V trigger wire for auto turn on. It has a mono 3.5 mm mini plug at each end. While you are unpacking your A 52+, inspect it thoroughly for possible shipping damage and tell your Parasound dealer immediately if you find any evidence of shipping damage.
Rack Mounting Your Parasound A 52+ With its four feet removed, the A 52+’s front panel height occupies three rack spaces: 5.25” or 133 mm. (A single standard rack space occupies 1.75” or 44.5 mm vertical height.) For mounting in a standard 19” equipment rack, you must use the Parasound HRA 3 rack mount kit (purchased separately). The HRA 3 kit includes four bolts and eight plastic washers with raised “shoulders.
Audio Connections Always disconnect the AC cord to your A 52+ before making or changing any input, output or trigger wire connections. Inserting or removing an input or output cable while the A 52+ is turned on can result in a blast of sound that can damage your loudspeakers. Make sure there is no strain or tension on any cables that could cause them to pull loose. Audio Input Connections Balanced XLR Input Jacks Balanced connections will give you the best sound.
Speaker Connections Speaker Terminals The A 52+ speaker terminals accept speaker wires with banana plugs, spade connectors or bare wire. Refer to “Bare Wire Speaker Ends” in the Technically Speaking section for information about bare wire termination. If you use spades make sure they are inserted vertically, without an angle. You want to prevent the tips of adjacent spades from touching and causing a short circuit. Correct Speaker Polarity is Important Polarity refers to + and – connections.
Turn On Options For convenience, there are three ways the A 52+ can be turned on and off: • Manually, by pressing the On-Off (Power) button on the front panel. • Automatically-Audio, when an audio signal is present at the audio Input jacks for channels 1 or 2. Channels 3, 4 and 5 can’t be used for audio turn on. • Automatically-12V, when a 12Vtrigger voltage is applied to the 12V input jack.
12V Position (Automatic on/off) When the Turn On Options switch is set to its 12V position, the A 52+ is turned on and off only with an external +9 V to + 12 V voltage from your surround processor, preamp or AV Receiver. When the external voltage ceases the A 52+ will turn off immediately. The Turn On Options switch 12V position disables the front panel On-Off button. 12 Volt Jacks 12V In Jack The A 52+ 12V input uses a 3.5mm jack (mono).
Front Panel Operation On-Off Button Push once to turn on the A 52+. When the A 52+ is turned on the dim blue glow around the On-Off button will become brighter and the five blue channel indicators will illuminate. Push the button again to turn off the A 52+. The front panel On-Off button will be disabled when the Turn On Options switch is set to Audio or 12V. Whenever the A 52+ is turned on, the soft blue glow behind its On-Off button changes to red for a few seconds until its internal circuits stabilize.
Technically Speaking Balanced and Unbalanced Lines Recording and broadcast studios use balanced connections exclusively because of their inherent ability to reject noise and hum, thus assuring the best sound. Certain high quality preamplifiers and surround controllers built for residential use utilize balanced connections with XLR jacks for the same reasons.
common AC outlet or power strip, you’ll avoid the problems created by resistance in the house’s wiring. Hum and buzz is also caused when unwanted voltage flows through multiple component ground points called ground loops. Here are three tips to avoid ground loops: 1. Your Cable TV or Satellite receiver box might require a Cable TV ground isolator. 2. Use balanced input lines with your Parasound A 52+. (See Balanced and Unbalanced Lines in this section). 3.
The Power Supply The heart of the 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.
The Driver Stage The driver stage provides critical amplification for which we employ a complementary matched pair of MOSFETs selected for their tube-like sonic qualities. MOSFETs tend to generate less odd-order higher harmonic distortion than bipolar transistors. This is important because odd-order distortion sounds unnatural and fatiguing to the human ear, whereas even-order distortion is less offensive because it is consonant, rather than dissonant.
Total Protection - Relays Each channel of the A 52+ has a high-quality protection relay with gold-plated contacts for long-term reliability. These relays function to protect either the amplifier, the speakers, or both. When the A 52+ is first powered on, these relays remain open for three seconds as the positive and negative power supplies stabilize and reach equilibrium. This prevents annoying popping or other transient noises.
Problems and Remedies Unit will not turn on • Check the setting of the Turn On Options switch. (The front panel On-Off button will be disabled if this switch is set to Audio or 12V) • If using Audio Turn on, try increasing the sensitivity of the audio trigger by turning the audio threshold knob to the “Quieter” position. • Check that the rear panel power switch is on and that the AC power is live. No sound from speakers • Check that input cables and speaker wires are secure at both ends.
Are You Having Difficulty? Repair or Service Call your Parasound dealer first. If the dealer can’t help you with your problem we encourage you to call Parasound’s Technical Service Department at 415-397-7100, Monday - Friday, 8am - 4pm Pacific Time. We can suggest other diagnostic tests you can easily perform.
Specifications Power Output - All 5 Channels Driven Input Sensitivity for 28.28 V Output into 8 Ω 180 watts x 5, 8 Ω 255 watts x 5, 4 Ω Unbalanced: 1 V Balanced: 1 V per leg Total Gain: 29 dB Power Output - 2 Channels Driven S/N Ratio 225 watts x 2, 8 Ω 350 watts x 2, 4 Ω > 112 dB, input shorted, IHF A-weighted > 102 dB, input shorted, unweighted Power measurements parameters with 120VAC: 0.
Parasound Products, Inc. 2250 McKinnon Ave, San Francisco, CA 94124 415-397-7100 / Fax 415-397-0144 www.parasound.
