ABSTRACT
Processing There are two identical processing channels for the left and right stereo signals. The preamplifiers, accept the signals from the input stage that is switched through to them. These are voltage amplifiers, as described in Topic 28. The amplitude of signals from the input stages is usually no more than a few milliamps. Typical supply voltages for amplifier circuits is 15 to 30 V, and amplification increases the signal amplitude in this range. Currents in these amplifiers are small, to avoid generating noise during the amplification of the low-voltage input (p. 109). It is essential to avoid introducing noise at the early stage, when the signal is small, for the later stages will amplify the noise along with the signal. There may be several stages of voltage amplification.
