Why the rear-panel number is not the whole answer
Amplifier output wattage is not equal to continuous mains consumption. Efficiency, channel loading and programme crest factor change the relationship. At the same time, assuming average draw is always low can underestimate a demanding sustained sequence or multiple subwoofer channels.
Use manufacturer current-consumption and recommended-circuit data wherever available. Note whether specifications describe idle, one-eighth power, typical programme or maximum conditions.
Circuits, voltage drop and inrush
A shared circuit can trip or sag when several large power supplies start together. Power sequencing, soft-start behaviour and separate circuits may be appropriate. Long cable routes and poor connections can add voltage drop and heat.
Multiple mains cords on one amplifier may serve separate power modules and must be connected exactly as specified.
Earthing and surge strategy
Protective earth is a safety function and must never be removed to cure hum. Coordinate earthing, distribution, surge protection and any backup power as one system. A consumer UPS may not tolerate high inrush or amplifier peak current; use only equipment suitable for the load.
South African installation context
Have a qualified electrician design, install and test the circuits in accordance with applicable South African requirements and the equipment manufacturers’ instructions. Label isolators and outlets, document circuit allocation, and verify supply voltage under a representative commissioning load.
Specification checklist
Before you decide
- List every rack load and mains cord.
- Obtain manufacturer consumption and circuit guidance.
- Plan sequencing and inrush.
- Maintain protective earthing.
- Require electrical testing and documentation.
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