T+A A 1560 User Manual

T+A A 1560 User Manual Manual pdf 30 page image

30Wiring variantsBi-Wiring (see Appendix A 3)The term Bi-Wiring refers to an alternative method ofwiring up loudspeakers, in which separate speaker leadsare used to carry the signals for the bass range and themid-range / high-frequency range.This system can only be used if your loudspeakers arefitted with bi-wiring terminals. It is essential to remove thebridging jumpers at the terminals.As the example wiring diagram shows, the unit isdesigned so that you can use the optimum type of cablefor each frequency range.Bi-Amping (see Appendix A 3)Bi-amping involves the use of two separate poweramplifiers, and they must be carefully matched, i. e.amplification factors, phase response and relative phasemust be absolutely identical.The signal paths for the bass range and the mid-range /high-frequency range are separated before they reachthe power amplifiers, so that each range is handled by itsown output stages, whilst remaining in separate stereochannels.This mode of operation increases the power reserves ofthe output stages, and this has a particularly positiveeffect on the overall dynamics of the system. For a givenvolume less power is required from each amplifier. Thisin turn reduces intermodulation effects and harmonicdistortion. The result is improved resolution and betterspatial location of the sound.In the example shown a power amplifier processes bothchannels of the mid-range / high-frequency range, whilean other power amplifier handles the bass speakers forboth channels.It is essential to remove the bridging plugs between thebass and mid-range/high-frequency channel at theloudspeaker terminals.All  power amplifiers can be used in bi-ampingmode, and combined with each other in any way youwish. The only restriction is that special cables areneeded for certain arrangements - please ask yourspecialist  dealer for details.Bridged MONO wiring(see Appendix A 4)The amplifier is connected to one channel of the pre-amplifier via the XLR or phono input (in the exampleshown the XLR input is used). It therefore receives aMONO signal.The pre-amplifier's other output channel must then beconnected to a second amplifier.Only one loudspeaker can be connected to output  A.Its nominal impedance must be no lower than 4 S(according to DIN).This arrangement excludes the possibility of signalcoloration as a result of error signals on the groundsystem, since in this mode of operation the output stages'signal ground system is not subjected to high outputcurrents. The amplifier's output power is more thandoubled in this mode.Note:When using more than one power amplifier it is essentialthat all the amplifiers and all the other systemcomponents are connected to a single wall socket, toavoid hum due ground loops.Bi-Wiring (bridged mode)(see Appendix A 4)In this variant of bi-wiring two separate power amplifiersare used, each driven in bridged MONO mode. Theamplifier is connected to one channel of the pre-amplifiervia the XLR or cinch input. It therefore receives a MONOsignal. The pre-amplifier's other output channel must thenbe connected to a second amplifier.This method of operation increases the system's powerreserves, and this has a very positive effect on thedynamics of the system. For a given volume a loweroutput is required from each amplifier, which in turnreduces intermodulation effects and distortion. The resultis improved resolution and better spatial imaging.