SIMPLY BETTER! B&K Components, Ltd. ST125.3 ST125.2 ST125.1 Owner's Manual P/N13437 0702 B&K B&K Components, Ltd., 2100 Old Union Road, Buffalo New York 14227-2725 Phone 1-800-543-5252 or (716) 656-0026, Fax (716) 656-1291 E-mail: info@bkcomp.com Web: www.bkcomp.com ii TABLE OF CONTENTS Table of Contents ....................................................................................................................................................iii Safety Precautions .................................................................................................................................................. 1 Purpose and Function............................................................................................................................................. 2 Design and Construction ....................................................................................................................................... 2 Features.................................................................................................................................................................... 2 Rear Panel ................................................................................................................................................................ 3 Level Adjustment..................................................................................................................................................... 4 Inputs ........................................................................................................................................................................ 4 XLR Balanced ....................................................................................................................................................... 4 RCA Unbalanced................................................................................................................................................... 4 Balanced or Unbalanced Connections.................................................................................................................. 5 Outputs ..................................................................................................................................................................... 6 System Installation .................................................................................................................................................. 7 Making the Connection ........................................................................................................................................... 7 Control Input and Output ........................................................................................................................................ 8 Troubleshooting ...................................................................................................................................................... 9 Care and Cleaning ................................................................................................................................................... 9 Specifications ........................................................................................................................................................ 10 Limited Warranty ................................................................................................................................................. 11 Returning Equipment........................................................................................................................................... 11 Rear Panel Enlarged Veiw .................................................................................................................................... 12 WWW.BKCOMP.COM ............................................................................................................................................ 13 iii SAFETY PRECAUTIONS PLEASE READ BEFORE INSTALLING WARNING: to prevent fire or shock hazard, do not expose this unit to rain or moisture. Care should be taken to prevent objects or liquid from entering the enclosure. Never handle the power cord with wet hands. · The lightning flash with arrowhead, within an equilateral triangle, is intended to alert the user of the presence of uninsulated "dangerous voltage" within the product's enclosure that may constitute a risk of electric shock to you. The exclamation point within an equilateral triangle is intended to alert the user of the presence of important operating and maintenance (servicing) instructions in the literature accompanying the unit. Caution: To prevent the risk of electric shock, do not remove cover. No user-serviceable parts inside. Refer servicing to qualified service personnel. Unplug the amplifier from the AC outlet when plugging in or unplugging cables, when left unused for an extended period of time, moving the amplifier, or when you suspect lightning in your area. Prevent damage to the power cord. Do not bend, pull, place objects on, alter, etc. Replace the power cord if it becomes damaged. Always grasp the plug on the power cord when plugging in or unplugging the amplifier from the AC outlet. Your system may produce sound levels capable of causing permanent hearing loss. Do not operate for extended periods of time at high volume levels. Make sure the amplifier is placed on a level surface. The amplifier is equipped with raised feet to provide ventilation, reduce acoustic feedback, and provide protection against scratching the surface the unit is resting on. We advise against removing or altering feet. Do not stack anything on top of the amplifier (processor, source, etc.) Leave a minimum of 2" clearance from the top of the amplifier to the next shelf (or component) to insure proper ventilation. The amplifier should be located away from other sources that may be sensitive to heat. Do not perform any internal modifications to the amplifier. Always connect the amplifier's power cord to an unswitched AC outlet for normal operation. If young children are present, adult supervision should be provided until the children are capable of following all rules for safe operation. Do not plug the amplifier's power cord into an outlet with an unreasonable number of other devices. Be careful if using extension cords and ensure the total power used by all devices does not exceed the power rating (watts/amperes) of the extension cord. Excessive loads may cause the insulation on the cord to heat and possibly melt. Mistaking CONTROL OUTPUT or CONTROL INPUT connectors for audio/video inputs or outputs may damage your amplifier or other components. Damage can occur to your speakers if the power rating of each individual driver is exceeded by the amplifier. Ensure that all the drivers in your system are capable of handling not only the average power being delivered by the amplifiers, but also the peak power that is likely to be generated during strong passages. If you are unsure of your speaker's power rating, contact the speaker manufacturer or the dealer where you purchased them. The amplifier should be serviced by qualified personnel when: A. The amplifier is not functioning properly. B. Objects have entered the chassis. C. The amplifier was exposed to rain or other type of moisture. D. The amplifier was dropped, or the chassis is damaged. · · · · · · · · · · · · · · · · 1 PURPOSE AND FUNCTION The ST125.3 (three channel), ST125.2 (two channel) and ST125.1 (mono) are high power amplifiers that are designed for use in all types of audio or audio/video systems. DESIGN AND CONSTRUCTION The ST125.3, ST125.2 and ST125.1 amplifiers utilize high quality electronic circuitry to achieve an environment wherein a detailed, transparent, and highly musical sound can be realized. The high quality parts complement includes: state-of-the-art solid state devices, 1% metal film resistors, computer grade electrolytic power supply capacitors, and a high capacity toroidal transformer. The ST125.3, ST125.2 and ST125.1 operate with a class A predriver and AB MOSFET power output stages. These high power amplifiers are capable of delivering their full rater power while reproducing the most demanding music passages effortlessly into the most demanding audiophile speakers. FEATURES Control Output - one 3.5 mm 12 VDC @ 125 mA output for turning on amplifiers and controlling external systems such as a projection screen or B & K amplifier. Control Input - one 3.5 mm jack that allows standby on/off with a 5-24 VDC control signal. Gold Plated Connectors - better sound with minimum signal loss and degradation. Toroidal Transformer - Efficient, high current, shielded transformer that supplies the amplifier with a clean and constant supply of power, even during highly demanding source material passages. Discrete Circuitry - Dynamically provides a full, accurate, and three dimensional reproduction of source material. Class A Predriver - Improves low level detail and clarity for smoother, more musical sound. AB MOSFET Output Stage - Provides efficient and linear power delivery, as well as protection from thermal overload. 1% Metal Film Resistors - Higher quality resistors for lower noise, better sound, and a greater degree of repeatability. High Current - Ability to cleanly, accurately, and reliably reproduce demanding recordings or source materials into low impedance drivers and speaker systems. Computer Grade Capacitors - Large capacity computer grade electrolytic capacitors for extended low frequency control, increased power supply, and improved dynamics. 2 REAR PANEL 8 7 * 6 * 5 * CONTROL I/O CONTROL IN ALLOWS AMPLIFIER OPERATION WHEN A 5-24V SIGNAL IS APPLIED WITH A 3.5mm MINI JACK + CHANNEL 1 INPUT CHANNEL 2 INPUT CHANNEL 3 INPUT CTRL IN XLR (BALANCED) XLR (BALANCED) XLR (BALANCED) CTRL OUT 12VDC 125mA S I M P LY B E T T E R ! RCA INPUT RCA (UNBALANCED) XLR INPUT RCA INPUT RCA (UNBALANCED) XLR INPUT RCA INPUT RCA (UNBALANCED) XLR INPUT B&K FUSE RISK OF ELECTRIC SHOCK DO NOT OPEN CAUTION CHANNEL 1 OUTPUT CHANNEL 2 OUTPUT CHANNEL 3 OUTPUT SERIAL # PLUS - + MINUS - PLUS + MINUS - PLUS + AC LINE 1 2 3 * 1. AC Fuse Holder - holds the AC Line fuse. This fuse is a 15 Amp / 250 Volt Slow Bow fuse. Replace only with the same type and value fuse. 2. AC Input Receptacle - for attaching the supplied AC power cord to the amplifier. 3. Speaker Outputs - for connecting the speakers to the amplifier. Explained further on page 6. * On the ST125.2, channel 3 is not available. On the ST125.1 mono amplifier, all output channels source the same information with the speaker outputs remaining fused independently. 4. Speaker Fuses - for protection against amplifier damage in the case of shorted speaker wires. Replace fuse with the same type and value 6 AMP T-Lag. * On the ST125.2, channel 3 is not available. On the ST125.1 mono amplifier, all outputs remain fused independently. 5. Balanced Input - for connecting signal patch cables (interconnects) from the preamplifier to the amplifier. Explained further on Page 4. * On the ST125.2, channel 3 is not available. On the ST125.1 mono amplifier, channels 2 and 3's XLR Balanced connections are not available. 6. Balanced/Unbalanced Input Select - this switch is used to configure an AMPLIFIER PAIR for use as either balanced (XLR) or RCA unbalanced line inputs. This switch controls two amplifier channels and allows signal patch cables (interconnects) to be sourced from either balanced or unbalanced, preamplifier/processor or line outputs. Explained further on Page 4. * On the ST125.2, channel 3 is not available. On the ST125.1 mono amplifier, channels 2 and 3's Balanced/Unbalanced Input Selectors, are not available. 7. RCA Input - for connecting signal patch cables (interconnects) from the preamplifier to the amplifier. Explained further on Page 4. * On the ST125.2, channel 3 is not available. On the ST125.1 mono amplifier, channels 2 and 3's RCA Unbalanced connections are not available. 8. Amplifier Control Input/Output - provides remote switching of the amplifier's standby on/off feature. Explained further on page 8. 3 E FU E FU E FU CAUTION: FOR CONTINUED PROTECTION AGAINST RISK O F F I R E R E P L A C E ON LY WI T H S A M E T Y P E A N D R AT I N G . SE SE SE FUSE FUSE FUSE 4 B&K Components, Ltd. Made in the U.S.A. www.bkcomp.com * FUS FUS FUS MINUS - LEVEL ADJUSTMENT Generally in a home theater application, volume level is controlled by the A/V surround processor. In a system for use with the ST125.3, ST125.2 or ST125.1, adjustment of the volume level must be performed using the external preamplifier/processor. INPUTS The ST125.3, ST125.2 or ST125.1, allows signal patch cables (interconnects) to be sourced from either balanced or unbalanced line level preamplifier/processor outputs. A switch is used to configure a PAIR of AMPLIFIER CHANNE ...