8.2 The power supply as a system

I declare: solidlikelyshaky

1. Read an amp’s supply: transformer, rectifier, filtering, symmetrical rails, and calculate the voltages unloaded and under load.
2. Explain why the power stage eats unregulated and the preamp regulated, and where the split happens.
3. Draw distributed decoupling: big capacitors at the reservoir, small ones near each stage, and why both.
4. Plan the power-up: inrush current, delay, turn-on noise (the "plop"), and what avoids it.
5. Size a device’s supply from each block’s consumption, with margin and heat.
6. Compare linear and switching supplies for an audio device: noise, weight, price, and where switching gets in anyway.
7. Diagnosis: a 60 or 120 Hz hum in the output, tired filtering, ground loop or transformer radiation; the measurements that decide.