User manual IMG STAGE LINE STA-1800

[. . . ] 13 Only for models STA-1800 and STA-2400: speaker connection OUTPUT BRIDGED MODE as a SPEAKER jack for bridge operation 14 Speaker connections OUTPUTS as SPEAKER jacks 15 Speaker connections OUTPUTS as screw terminals with 4 mm banana jacks 16 Jacks INPUTS as XLR jacks for units with line level 17 Only for models STA-1800 and STA-2400: Mains cable for connection to a socket (230 V~/ 50 Hz) 18 Operating mode switch MODE position STEREO: stereo operation position PAR: parallel operation position BR: bridge operation 19 GROUNDLIFT switch position GND: signal ground and housing ground are connected position LIFT: signal ground and housing ground are separated 20 LIMITER switch position ON: limiter is switched on position OFF: limiter is switched off 21 Switch for the SENSITIVITY of the input to select the input voltage at which a rated power is reached 22 Jacks INPUTS as 3-pole 6. Mixer, preamplifier) 23 Only for models STA-800 and STA-1100: fuse holder; only replace a blown fuse by one of the same type 24 Only for models STA-800 and STA-1100: mains jack for power supply at 230 V~/50 Hz 1 POWER LED ON 2 LED PROT lights up with activated protective circuit of the left channel: for a few seconds after switching-on until the speaker outputs are ready for operation and if the protective circuit has switched off the speakers in case of a defect 3 LED BR lights up if the switch for the operating MODE (18) is in position BR 4 LED SIG lights up if a signal is present with the volume control for the left channel turned up 5 LED CLIP lights up if the left channel is overloaded and if a short-circuit occurs at the left output 6 Volume control for the left channel 7 POWER switch 8 Volume control for the right channel 9 LED CLIP lights up if the right channel is overloaded and if a short-circuit occurs at the right output 10 LED SIG lights up if a signal is present with the volume control for the right channel turned up 11 LED PAR lights up if the switch for the operating MODE (18) is in position PAR 12 LED PROT lights up with activated protective circuit of the right channel: for a few seconds after switching-on until the speaker outputs are ready for operation and if the protective circuit has switched off the speakers in case of a defect This unit corresponds to the directive 89/336/EEC for electromagnetic compatibility and to the low voltage directive 73/23/EEC. Furthermore, any guarantee claim will expire if the unit has been opened. There is a hazard of contact at the speaker connections with a dangerous voltage during operation. [. . . ] If the unit is to be put out of operation definitively, take it to a local recycling plant for a disposal which is not harmful to the environment. This PA stereo has especially been designed for stage and disco applications. The amplifier is provided for rack installation (482 mm/19"), but it may also be used as a table top unit. In each case air has to move through all ventilation slots without obstruction so that a sufficient cooling is ensured. Additional space should remain above and below the amplifier to ensure a sufficient ventilation. To prevent the rack from becoming top-heavy, the amplifier has to be mounted in the lower part of the rack. The unit has additionally to be supported by side rails or a bottom plate. Both jacks are provided for balanced signals; the pin configuration is shown in figures 4 and 5. 2) The maximum output power is reached in 2-channel operation (stereo or parallel) when connecting 4 speakers. Speakers, however, the output power will slightly decrease in this case. In bridge operation the maximum output power will be reached with an 8 speaker. When using the SPEAKER jacks (14), the contact pairs 1+/1- or 2+/2- can be used, as in the unit the contact 1+ is connected to 2+, and the contact 1- to 2-. When connecting the speakers, pay attention to the same polarity of all speakers. For bridge operation connect the positive pole of the speaker to the positive terminal of the left output and the negative pole of the speaker to the positive terminal of the right output. 6 also shows possibilities of connection for several speakers to one output. In each case it is stated which power rating (PMIN) each speaker must have as a minimum with the corresponding impedance (Z). When interconnecting several speakers, it is especially important to pay attention to the correct connection of the positive and negative contacts and that the minimum total impedance is 4 for 2-channel operation and 8 for bridge operation. Prior to the first switching-on, set the controls (6 and 8) to the left stop to - . Adjust the output of the mixer or preamplifier to its rated level (0 dB) or the maximum undistorted output signal. With the switch SENSITIVITY (21) match the input sensitivity of the amplifier to the output level of the mixer or preamplifier. [. . . ] If a DC voltage occurs at the output If a short circuit occurs at the speaker output, the CLIP LED (5, 9) of the corresponding channel lights up. If this is the case or if the LED PROT lights up during operation or if it is not extinguished after switching-on, the amplifier must be switched off and the cause for the defect must be eliminated. If an interfering hum noise can be heard without a music signal, a ground loop may be the reason for this. Ground loops may occur if two units have contact both via the signal ground and via the earthed conductor of the power supply or a conductive connection of the housings in the rack. [. . . ]