desing of amplifier audio for headset

2. The technical data of intercom SPU-7 are the following: a) power supply, on-board DC power supply with a voltage of 27 V ± 10%; b) power to be consumed by the kit (taking into account an amplifier and six persons devices), up to 50 W; c) output voltage in six pairs devices of headset (high ohmic resistance) when supplying. .a voltage of 0.5 V and 1000 Hz at the input of the amplifier through the equivalents of the headset and the position of the amplification regulator of the amplifier of 45 to 70 V. maximum; d) variation of the output voltage, by varying the number of activated equivalents of the TM-56M type laryngóphones from six pairs to two pairs, by 20%. at most; e) change in output voltage by varying the number of activated equivalents of the headset from two pairs to one pair, by 25%. at most; g) frequency band of 300-3500 Hz. h) supply voltage in a pair of the headset must be 4.5 ± 0.6 V: i) supply voltage of the headset in steady state must not: exceed 10 V.