Page 2 - Important Safety Instructions
2 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 i...
Page 3 - Table of Contents
3 Table of Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Placement and Ventilation Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 AC Mains Voltage . . . . . . . . . . . . . . . . . . . . . . . . . ....
Page 4 - INTRODUCTION
4 INTRODUCTION Thank You for Choosing Parasound Your new Parasound Halo A 31 power amplifier has been designed with the most advanced, proven class A/AB amplifier technology. The A 31 is built to extremely strict quality and performance standards for which Parasound is renowned. We’re proud to offer...
Page 5 - Unpacking Your A 31 & Placement Guidelines; AC Mains Voltage; NOTE: Before you plug this amplifier into an AC mains outlet:
5 Unpacking Your A 31 & Placement Guidelines Unpacking Your A 31 Carefully remove your A 31 from its shipping carton and locate the enclosed accessories: • AC power cord • Two trigger wires, one with 3.5 mm mini plugs, one with a 2.5mm and a 3.5mm mini plug While you are unpacking your A 31, ins...
Page 6 - Rack Mounting Your Parasound A 31
6 Rack Mounting Your Parasound A 31 To mount the A 31 into a 19" wide equipment rack, you must first attach its two “L” shaped rack mount brackets (included). With its four feet removed, the A 31 chassis and front panel height occupies four rack spaces (7" or 176 mm). When mounting equipment...
Page 7 - Audio Connections; Audio Input Connections
7 Audio Connections Always disconnect the AC cord to your A 31 before making or changing any input, output or trigger wire connections. Inserting or removing an input or output cable while the A 31 is turned on can result in a blast of sound that can damage your loudspeakers. Make sure there is no s...
Page 8 - Speaker Connections
8 Speaker Connections Speaker Terminals The A 31 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. Correct Speaker Polarity is Important Polarity ...
Page 10 - Turn On Options
10 Turn On Options For convenience, there are three ways the A 31 can be turned on and off: • Manually , by pressing the On-Off (Power) button on the front panel. • Automatically , when an audio signal is present at any of the audio Input jacks. • Automatically , when a suitable trigger voltage is a...
Page 11 - AC Power Cord
11 12 Volt Jacks 12V In Jack The A 31 12V input uses a 3.5mm jack (mono). To use the 12V trigger, insert the trigger wire plug into this jack and the plug at the wire’s other end into the AV receiver or preamp’s 12V output jack. We have included a 3.5mm to 3.5mm trigger wire as well as a 3.5mm to 2....
Page 12 - Front Panel Operation; Channel Indicators
12 Front Panel Operation On-Off Button Push once to turn on the A 31. When the A 31 is turned on the blue glow around the On-Off button will be brighter, the red P badge will glow brighter and then the 3 channel indicators will illuminate blue. Push again to turn off the A 31. The front panel On-Off...
Page 13 - Technically Speaking
13 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 ut...
Page 14 - Parasound A 31 Design Overview
14 1 . Your Cable TV or Satellite receiver box might require a Cable TV ground isolator. 2 . Use balanced input lines with your Parasound A 31. (See Balanced and Unbalanced Lines in this section). 3 . When rack mounting, always use the insulated “shoulder” washers. These break the ground loops cause...
Page 17 - Problems and Remedies
17 Total Protection - Current Overload Specialized current-sensing transistors are connected to the output stages of the A 31 to constantly monitor the current flow through the output transistors. If the current drawn by this stage exceeds a predetermined safe level due to a load impedance below 1 o...
Page 18 - Are You Having Difficulty?
18 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 ...
Page 19 - Specifications
19 Input Sensitivity for 28.28 V Output into 8 Ω Unbalanced: 1 V Balanced: 1 V per leg (Gain controls set to Normal / THX) S/N Ratio > 112 dB, input shorted, IHF A-weighted > 102 dB, input shorted, unweigh Damping Factor > 1100 at 20 Hz DC Trigger Requirements +9 Vdc to +12 Vdc, 2 mA Audio ...
