User manual B&K ST1200 II

[. . . ] B & K Components Ltd. P/N 12687 B&K Components, Ltd. , 2100 Old Union Road, Buffalo, New York 14227 Safety Precautions Purpose and function Design and construction Features Rear panel view Rear panel description Control muting Level controls Inputs Outputs Internal Bus Jumper description Mono application Bridged application System installation Making the connection Troubleshooting Care and cleaning Specifications Warranty Manual and Power cord Page 2 Page 3 Page 3 Page 4 Page 4 Page 5 Page 5 - 6 Page 6 Page 7 Page 8 Page 9 Page 9 - 10 Page 11 Page 12 Page 13 Page 13 - 14 Page 15 Page 15 Page 16 Page 17 Page 1 WARNING: TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS UNIT TO RAIN OR MOISTURE. 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 be sufficient magnitude to 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. Observance of polarity is essential. Double-check connections before turning the amplifier on. The amplifier can be damaged if polarities are incorrect. [. . . ] They are designed to accept a banana-type plug or spade lug connector (shown below) and are color coded for easy identification. The red (+) post should always be connected to the speakers (+) jack. The black (-) post should always be connected to the speakers (-) jack. Spade connector Banana jack Here is a typical amplifier setup: Page 8 In order to gain access to the internal bus structure, you must first remove the top cover. Turn the amplifier so the rear panel is facing your. The jumper modules may be seen on the circuit board just behind the level controls. Below is the default setup for the ST1200 series II amplifier. By arranging the jumpers allows you to configure the amplifier for different applications. If you wish to use the amplifier as a stereo (two channel) amplifier, you need not change any of the settings. In order to reconfigure the ST1200 series II's channels, remove the source control group jumper from its present position (if necessary) and install it on the terminal you wish to select as the source for that channel. Make sure it has been inserted on both terminal pins of the jumper modules. To complete the configuration, the volume group jumper should be placed at either the `USE VOL' or `NO VOL' terminal depending on you configuration. Figure G illustrates the jumper modules used in configuring each channel. Each jumper terminal location is conveniently labeled as to the source it can be configured to provide. Explained further on the following page. Page 9 Along with being the right channel input, it is used as the input to the right bus and the right source for the `L+R BUS'. Because it is a BUS input, any signal input here will appear at the `R BUS' jumper terminal for both of the ST1200 series II's jumper modules. Installing a jumper plug at this terminal on either of the two internal jumper modules selects the combined signal being carried by both the left and right inputs. If the left bus and right bus are being used to carry stereo right and left channels, a jumper plug installed at the `L+R BUS' location will provide a true L+R mono output. Along with being the left channel input, it is used as the input to the left bus and the left source for the `L+R BUS'. Because it is a BUS input, any signal input here will appear at the `L BUS' jumper terminal for both of the ST1200 series II's jumper modules. If volume control is desired only from the source, or if outputs are being combined to obtain higher power, the jumper plug should be installed at the `NO VOL' location. If volume control is desired at the amplifier, beyond that provided at the source, a shorting plug is installed at the `USE VOL' location. The `USE VOL' setting be used when channels are bridged or combined. This is a single jumper module that is set apart, up and to the right from the channel jumper modules on the circuit board. It provides a special function, when the jumper is set on the `-L' pins, the left bus signal feeding the left channel will be inverted. Page 10 The ST1200 series II's two output channels may be paralleled (mono) to combine the left and right channels output current. This feature allows the amplifier to double its apparent output current. [. . . ] Replace blown rail fuse inside amplifier. Loud hum or buzz on one or more channels Low output from amplifier 1. 1. Poor ground connection in interconnect cables. Balanced switch in balanced mode when using unbalanced inputs. 1. Channel sounds distorted and low in output 1. 1. ** Note: If unit continues to blow power inlet fuses, have it serviced. Under normal use, the amplifier will not require any special care. [. . . ]