SIMPLY BETTER! B&K Components, Ltd. ST55.2 OWNER'S MANUAL B&K P/N13436 0702 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 Control Muting ......................................................................................................................................................... 4 Level Controls.......................................................................................................................................................... 5 Inputs ........................................................................................................................................................................ 5 Outputs ..................................................................................................................................................................... 5 Internal Bus Structure ............................................................................................................................................. 6 Jumper Description ................................................................................................................................................. 7 Mono Application (Medium Current) ..................................................................................................................... 7 Bridged Application (High Voltage) ....................................................................................................................... 8 System Installation .................................................................................................................................................. 9 Making the Connection ........................................................................................................................................... 9 Troubleshooting .................................................................................................................................................... 10 Care and Cleaning ................................................................................................................................................. 10 Specifications ........................................................................................................................................................ 11 Limited Warranty ................................................................................................................................................................12 Returning Equipment .........................................................................................................................................................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 ST55.2 is a compact, very efficient, two channel power amplifier. It is designed for use in all types of audio or audio/video systems. The term versatile is almost adequate to describe the variance of operational modes the ST55.2 is capable of providing. This is all accomplished through the simple placement of internal jumpers and the paralleling or bridging of its outputs and/or linking multiple ST55.2's. Here is a listing for some of the many tasks it can be set up to perform: · The most obvious function for the ST55.2 is to take 2 separate audio inputs, such as a stereo pair, and provide 2 separate amplified outputs. Your ST55.2 has arrived set up in this configuration. With the inputs buffered, a line output (OUT BUS) may be taken from the L BUS, R BUS, or L+R BUS and sent on to another amplifier. This allows for linking of multiple amplifiers. Continuing its versatility, the ST55.2 may be used mono to provide one, medium current channel in order to drive a speaker requiring more power. As a result of the ST55.2's unique bus system, the input to the left channel may be inverted thereby allowing the possibility of creating a single high voltage (bridged) channel from one source, through the left bus. · · · DESIGN AND CONSTRUCTION The ST55.2 utilizes high quality electronic circuitry to achieve an environment wherein a detailed, transparent, and highly musical sound can be realized. The high quality complement of parts, include state-of-the-art solidstate devices, 1% metal film resistors, computer grade electrolytic power supply capacitors, and a high capacity toroidal transformer. FEATURES Toroidal Transformer - Efficient high current transformer for improved dynamics. Discrete Circuitry - More accurate and three dimensional reproduction of source material. Limited Protection - Provides short term protection from accidental shorting of output devices and protection from thermal overload. Gold Plated Connectors - Improve connections for better sound and minimized signal loss and degradation. 1% Metal Film Resistors - Low noise resistors for better sound and a greater degree of repeatability. Medium Current - Ability to reproduce demanding recordings. Computer Grade Capacitors - Large capacity computer grade electrolytic capacitors for extended low frequency control and improved dynamics. 2 REAR PANEL 7 6 5 4 RISK OF ELECTRIC SHOCK DO NOT OPEN CAUTION FUSE CAUTION: FOR CONTINUED PROTECTION AGAINST RISK O F F I R E R E P L A C E O N LY W I T H S A M E T Y P E A N D R AT I N G . WE SIMPLY SOUND BETTER. LO HI LO HI B&K SERIAL # LEVEL CONTROLS R LEVEL L LEVEL BUS INPUT LEFT BUS OUTPUT LEFT CONTROL I/O CTRL IN ENABLE CTRL IN RIGHT MONO RIGHT D E F E AT 12VDC 125mA CTRL OUT MINUS PLUS PLUS MINUS B&K Components, Ltd. Made in the U.S.A. www.bkcomp.com WHEN SWITCH IS SET TO ENABLE, THE AMPLIFIER WILL ONLY OPERATE WHILE A 5-24VDC SIGNAL IS APPLIED TO CTRL IN - RIGHT AC LINE LEFT 1 2 3 1. AC fuse holder - Holds the AC Line fuse. This fuse is an 8 Amp / 250 Volt Slow Blow fuse. Replace with same type and value fuse only. 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 8. 4. Amplifier control muting input/output - To provide remote switching of mute on/off of the amplifier. Explained further on page 5. 5. Line level outputs - For connecting signal to another amplifier (daisy chaining). 6. RCA inputs - For connecting signal patch cables (interconnects) from the preamplifier to the amplifier to pass signal. 7.Level controls - For adjusting the input level to the amplifier. Explained further on page 6. 3 CONTROL MUTING A control is provided on each ST55.2 amplifier to allow remote switching of mute on/off. The preamplifier's control output, such as is provided with B&K series preamplifiers, can be utilized to provide a control signal to the ST55.2. If more than one amplifier is being controlled, the control signal can be extended to include each successive unit by simply running an RCA type audio cable from the CTRL OUT connector of the first amplifier to the CTRL IN connector of the next unit (commonly referred to as `daisy chaining'). An example of how to connect two amplifiers is illustrated in the figure below. If a source other than a B&K series preamplifier is used to control multiple amplifiers, only the control output voltage from the source is critical. It must be within the range, as indicated on the rear panel, 5-24 volts DC is required. The amplifier will provide each successive amplifier with a control voltage of 12 volts DC for reliable operation. The amplifiers control output may be used as a source of 12 VDC @ 125 mA for other user applications as well. DO NOT POWER MOTORS WITH THIS CIRCUIT. Rear View of Second Amplifier with Control I/O CONTROL I/O CTRL IN ENABLE CTRL IN Rear View of First Amplifier with Control I/O CONTROL I/O CTRL IN ENABLE CTRL IN From Preamplifier Control Output 12VDC 125mA CTRL OUT 12VDC 125mA CTRL OUT D E F E AT D E F E AT WHEN SWITCH IS SET TO ENABLE, THE AMPLIFIER WILL ONLY OPERATE WHILE A 5-24VDC SIGNAL IS APPLIED TO CTRL IN WHEN SWITCH IS SET TO ENABLE, THE AMPLIFIER WILL ONLY OPERATE WHILE A 5-24VDC SIGNAL IS APPLIED TO CTRL IN Daisy Chain To Other Amplifiers Control Enable Button OUT If the control function is desired, each unit in the system must remain connected at al ...