A 23+ Stereo Power 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 AC Mains Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Front and Rear Panel Drawing Rack Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INTRODUCTION Thank You for Choosing Parasound Your new Parasound Halo A 23+ power amplifier has been designed with the most advanced, proven class A/AB amplifier technology. The A 23+ 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 23+ & Placement Guidelines Unpacking Your A 23+ Carefully remove your A 23+ 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 23+, 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 23+ With its four feet removed, the A 23+’s front panel height occupies two rack spaces: 3.5” or 88.2 mm. (A single standard rack space occupies 1.75” vertical space.) For mounting in a standard 19” equipment rack, you must use the Parasound HRA 2 rack mount kit (purchased separately). The HRA 2 kit includes four bolts and plastic washers with raised “shoulders.” Slide one washer onto each mounting bolt with its raised shoulder pointing toward the panel hole.
Bridged Mode Bridged operation configures the Left and Right channels to function as a single channel higher power amplifier to drive a single speaker. When an A 23+ is in Bridged Mode it provides far greater power output than the sum of its left and right channels’ power output. Please note that in bridged operation the minimum speaker impedance is 8 ohms. We do not recommend using the A 23+ with a 4 ohm speaker while set to bridged mode.
Speaker Connections Speaker Terminals The A 23+ speaker terminals accept speaker wires terminated with banana plugs, spade connectors or up to 10 AWG bare wire. Bare Speaker Wire Ends If you plan to connect your speaker cables with bare wire ends, use a wire stripper to remove just enough insulation to expose a 1 2" (13 mm) length of bare wire. You can insert the stripped wire into the hole that goes vertically through each terminal’s metal post.
Turn On Options The setting of the rear panel Turn On Options switch determines how the amplifier turns on and off. Setting the Turn On Options switch to Audio or 12 V disables the A 23+’s front panel Power button. There are three positions for this switch: Manual: When the Turn On Options switch is set to Manual the A 23+ is turned on and off manually only by pressing the Power button on its front panel every time you want to listen to music.
12 V In Jack The A 23+ 12 V input uses a 3.5 mm jack (mono). To use the 12 V trigger, insert the trigger wire plug into this jack and the plug at the wire’s other end into your preamplifier’s 12 V output jack. For your convenience we have included a 12 V trigger wire with mono 3.5 mm plugs at both ends. The A 23+ 12 V trigger circuit draws a negligible 5 mA. Note: If your preamplifier’s 12 V trigger output is terminal with + and – screws terminal, you can cut the 3.
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.
Parasound A 23+ Design Overview Circuit Designed by John Curl Parasound design consultant John Curl has been a legend among audiophiles and electronic engineers for decades.
Audio Circuit Path Topology Parasound’s circuit topology is a hybrid of carefully chosen discrete transistors that result in superior performance at each stage. We use JFETs (Junction Field Effect Transistors) for the input voltage amplifier stage; MOSFETs (Metal Oxide Field Effect Transistors) for the drivers of a second voltage amplifier stage and bipolar transistors for the current amplifier output stage.
Total Protection - DC Servos Even a miniscule amount of Direct Current (DC) will burn out speakers without any warning. Every power amplifier must have some way to insure that DC from its power supply never reaches its + or - speaker terminals. Most amplifiers simply use adjustable trim controls to reduce their DC offset or capacitors to block DC.
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 12 V) • 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 – Stereo Mode (0.06% THD) Total Gain 160 watts x 2, 8 Ω both channels driven 240 watts x 2, 4 Ω both channels driven 29 dB Input Sensitivity for 28.28 V Out (8 Ω Load) Power Output – Bridged Mode (0.06% THD) Unbalanced: 1 V Balanced: 1 V per leg 500 watts x 1, 8 Ω Bridged 4 Ω operation is not recommended S/N Ratio Power Output – Stereo Mode (0.
Parasound Products, Inc. 2250 McKinnon Ave, San Francisco, CA 94124 415-397-7100 / Fax 415-397-0144 www.parasound.
