switch-on delay - for power amplifiers

.for power amplifiers There is no doubt about the value of a switch-on delay for a power amplifier. We all know the irritating (and potentially damaging) pop heard from the loudspeakers when the power amplifier is switched on or off. The circuit described here pro- vides a technically simple, but nonetheless satisfactory, solution to this problem. A relay is used to isolate the loudspeakers until the switch-on surge has passed, as this is what causes the loudspeakers to pop. Switching off an amplifier may also cause loudspeakers to pop so this circuit prevents this happening by switching the "speakers out of circuit just before this happens. As the diagram shows, we have kept the circuit as simple as possible. Because of this the circuit is both in- expensive and easy to build. One slight disadvantage of this design is that it can only be used with a power amplifier that has a sym- metrical power supply (with a maxi- mum of ± 60 V). This is not really such a big problem as most m...