User manual ALTEC LANSING 288-8L HF DRIVER

[. . . ] 7 7 7 7 8 8 8 8 9 9 8 SELF-PROTECTION FEATURES . 10 8. 5 Unacceptable DC or High Frequency Output Content . 10 11 11 12 12 9 2 Operating Manual 6125A and 4200A Multi-Channel Power Amplifier 10 DESIGN THEORY . 15 Caution: produce dangerous This power amplifier can produce dangerous output voltage levels, high re order pre power levels, and high sound pre s s u re levels in loudspeakers. [. . . ] The 4200A is essentially two stereo amplifiers in one chassis, for a total of up to four separate channels. Thus, the following references to Stereo, Mono, or Bridged operation is with regard to each of three or two pairs of channels in the amplifier. For example, Channel 1 and Channel 2 together can provide stereo, mono, or bridged operation, completely independent of Channels 3-4 or Channels 5-6 settings. 7. 4 50Hz Low Cut Switch Each pair of channels has a 50Hz second order (12 dB per octave) low-cut filter option which is applied to both channels within the pair. When the switch is pressed, the audio signal is -3dB at 50Hz, -15dB at 25 Hz, -27dB at 12. 5Hz, etc. +- G Euroblock Connector System +- G 7 Operating Manual 6125A and 4200A Multi-Channel Power Amplifier Model 6125A shown. Model 4200A has only four channels. 7. 5 Input Level Controls Input Level Controls attenuate input signal from 0dB down to -. For best performance, Altec recommends that the level controls be operated at full level (0 dB attenuation). In STEREO mode, each level control corresponds directly to the input signal on its respective channel. In MONO Mode, the input signal connected to channels 1, 3, or 5 are used to drive channels 2, 4, or 6 respectively, and the level controls for channels 1, 3, and 5 likewise control channels 2, 4, and 6. When switched to Mono mode, channels 2, 4, or 6 level controls become inactive. In BRIDGED mode, the level controls function the same as in mono mode. other input connection, as well as its level control. The amplifier is now ready for use at the new mains voltage. If the mains voltage is 110-125VAC, the required fuse is MDA 12, 250V, and the required power cord is 3wire grounded, 13 Amp (16AWG) minimum. If the mains voltage is 220-250VAC, the required fuse is MDA 10, 250V, and the required power cord is 3wire grounded, 10 Amp (18AWG) minimum. SELF-PROTECTION FEATURES The 6125A and 4200A amplifiers contain circuitry to self-protect during extreme fault conditions. These fault conditions are: 1. ) 2. ) 3. ) 4. ) 5. ) 6. ) Power supply undervoltage Power supply overvoltage Output overcurrent Heat sink overtemperature Unacceptable DC or high frequency output content AC power interruption Except for AC power interruption, the detection of any fault will result in the activation of protection circuitry on a particular module, which consists of two channels. That is, a short circuit on the output of channel 1 will result in both channel 1 and channel 2 entering protect mode. This is because the signal processing module, which processes both channels simultaneously, does not distinguish between the two channels within a channel pair when processing a fault. An AC power interruption will result in all channels entering protect mode simultaneously, just as if the amplifier is being turned off. 9 Operating Manual 6125A and 4200A Multi-Channel Power Amplifier In all cases, the amplifier will restart the signal processing module after a short delay and will reconnect the speakers after several seconds if no further fault conditions exist. This allows the servo circuitry to bring any residual DC offsets to zero before speakers are connected. Specific conditions resulting in a fault are as follows: 8. 1 Power supply undervoltage - less than about 55 volts on the either supply rail. Possible causes would be total load on the outputs exceeding recommendations (remove some speakers - 4 load min, 8 min bridged), low AC mains voltage (reduce extension cord length or increase wire size, or switch to an AC mains circuit more capable of supporting the amplifier's power requirements), or improper AC inlet mains voltage setting (make sure nominal AC mains voltage matches the number in the viewing window on the AC inlet). 8. 2 Power supply overvoltage - more than about 92 volts on either supply rail. [. . . ] When using paralleled speakers, the available amplifier power for that channel is evenly divided among speakers, so 100 watts driving two parallel speakers of equal impedance provides 50 watts to each speaker, etc. 3. ) Thermal LED and Protect LEDs stay on: Amp module is in thermal protect mode and needs to cool. The fan will continue to run while in thermal protect, and other modules will continue to function. 4. ) Power LED lit but no Signal LED activity There is no input signal applied or input level controls are turned down. 13 Operating Manual 6125A and 4200A Multi-Channel Power Amplifier 11. 2 Distorted Sound 11. 3 Hum or Buzz Noise 1. ) Clip LED is flashing regularly Amplifier is being overdriven. [. . . ]