Balanced Audio Line Driver Circuit

Floating balanced line drivers.

Balanced audio line driver circuit.

Balanced unbalanced converter for audio work. The response graph shows the measured frequency response with the differential feed a balanced line driver figure 1 and receiver figure 2. By walt jung and adolfo garcia download pdf. In this article we consider audio line drivers and receivers.

The common mode output resistance a common voltage applied to the output will cause a considerable common mode current into the. These balanced audio drivers consist of high performance op amps with on chip precision resistors. The first article in this series analog dialogue 26 2 covering general line driving and buffer design considerations gave examples of video line driver and receiver designs. In telecommunications and professional audio a balanced line or balanced signal pair is a transmission line consisting of two conductors of the same type each of which have equal impedances along their lengths and equal impedances to ground and to other circuits.

Goes to the next circuit s audio input or ts tip ground unlabeled on pcb goes to the next circuit s audio ground or ts sleeve balanced output. The drv134 and drv135 are differential output amplifiers that convert a single ended input to a balanced output pair. However in some cheaper balanced line drivers one core does not carry any signal but is grounded instead. The following data taken from the thd test circuit on an audio precision system one using the internal 80 khz noise filter demonstrates the typical performance of a balanced.

This balanced audio driver consists of high performance op amps with on chip precision resistors. Op amps in line driver and receiver circuits part 2. The audio input should be an unbalanced professional 4dbu line level audio signal. The mini board converts unbalance audio signal into balance audio signal the project is based on ssm2142 or drv135 ic which are differential output amplifier that converts a single ended audio signal input to a balanced output pair.

The signal is 1db down at 10hz and 30khz which is pretty good considering the overall simplicity of the circuits. You can wire the balanced output directly after an unbalanced circuit or to a ts 2 pin 1 4 jack. They are fully specified for high performance audio applications. The chief advantage of the balanced line format is good rejection of external noise when fed to a differential amplifier.

There is nothing to grumble at but there is one essential difference between an output like the described one and a transformer coupled one. A balanced line driver ssm2142 features transformer like balanced output drives 10 v rms into a 600 v load stable when driving large capacitive loads and long cables. Open in new find other audio line drivers description. So in this case amplifier 2 is left out and the left hand side of resistor r2 is grounded.