Why do you keep talking about noise and voltage spikes?
The problem is in narrow current spikes (pulses) charging capacitors that increase power losses on any impedance in series.
During orchestra forte voltage on power supply caps drops. It is because of capacitor ESR, but also because of voltage drops on on transformer windings (copper losses) and any other impedance in series including power cord, house wiring, conditioner coil etc. Simply, power supply is not load regulated (voltage vary with load). Some unregulated supplies are better than the others often because they have oversized transformers. Increasing capacitance should also help, but creates another problem - lower voltage ripple that results in much narrower and much higher charging current pulses, that will create even more power losses (including core losses for hysteresis and eddy currents because of high frequency content).
The problem is in narrow current spikes (pulses) charging capacitors that increase power losses on any impedance in series.
During orchestra forte voltage on power supply caps drops. It is because of capacitor ESR, but also because of voltage drops on on transformer windings (copper losses) and any other impedance in series including power cord, house wiring, conditioner coil etc. Simply, power supply is not load regulated (voltage vary with load). Some unregulated supplies are better than the others often because they have oversized transformers. Increasing capacitance should also help, but creates another problem - lower voltage ripple that results in much narrower and much higher charging current pulses, that will create even more power losses (including core losses for hysteresis and eddy currents because of high frequency content).