here is why inductor-based power conditioners don't work well for your typical power amplifiers.
A linear power supply works by first rectifing the ac mains (fed through the 2ndary of a power transformer) and then feed it to a filter capacitor. The rectifier, which allows the current to flow only in one direction, charges up the capacitor, and the capacitor maintains rail voltage when the rectifier is not conducting.
the problem this combination creates is that a) to have as constant a rail voltage as possible for high power applications, you need to have as big of a capacitor so that it stores as much energy. b) as the rail voltage gets more stable, the time during which the rectifier can conduct gets shorter. However, the same amount of energy has to be passed onto the capacitor (and then to the load) in a shorter period of time through the rectifier, the current going through the rectifier gets progressively higher - in spite of the fact that the current in RMS terms is the same.
As the current burst gets shorter in duration and higher in magnitude, the "high frequency" content of it gets bigger - this is sometimes referred to as the "RF" problem in a low frequency rectification.
What is an inductor? in this context, you can think of it as a frequency-dependent resistor, a resistor that has higher "resistance" for high frequency signals, and lower "resistance" for low frequency signals. so a high frequency signal will lose more as it goes through an inductor - this is why an inductor can eliminate high frequency signals from your ac mains - or "clean it up" as some of us likes to call it. As you can see, a bigger inductor (with higher inductance) will do a more effective job at cleaning up the dirty mains.
Here is foundamentally the issue here: good rectification for high power applications calls for constant rail voltage, which necessarily creates high frequency content, which has more difficulties get passed through an effective power conditioners. or the power supply gets choked by the power conditioners.
Here is some spice simulation for you to see it visually.
This is a typical power supply. As we are only interested in a half cycle, I used half wave rectification and we shall focus on the positive cycle - the negative half in a typical bridge rectification is identical.
V1 is the power source from your transformer secondary. It is a 42vp 50hz signal with no DC content. V2 is our "pollutant" that we will talk about later. D5, MUR860, is our rectifier. This is an ultra-fast type used quite often in high-end audio applications. C1 is the filter cap, with 11,000uf capacitance (again, quite typical). I1, is the load, with 4amp average current drain, and 4amp current swing, and at 20khz - kind like a 32v 20khz signal on a 8ohm speaker.
The blue probe shows the voltage on the rectifier's anode side, and the organce probe shows the rail voltage. the green probe shows the current going through the rectifier. As you can see, we are getting about 40vdc out of this setup. the repeatitive peak current through the rectifier is about 50amp, in spite of the fact that our average load is only 4amp.
Also notice how big the initial charge-up current is: ~140amp!
Let's now pollute the nice ac mains with a 10vp 1khz signal - this is actually roughly the amount of high frequency signal generated by the rectification but that's for another discussion.
Here is again the waveform.
the inductor, L1, is very small at 10uh so it is as if it is not in the loop. Notice that when the voltage from the 2ndary (the blue probe) is quite dirty, the rail voltage (the organge probe) is unaffected, at about 40vdc. This shows you why a power conditioner is NOT needed for rectification.
Peak current through the rectifier, the green probe, has higher peak figures because of the 50% duty cycle of the pollution.
the take-away? a) you don't need a power conditioners to get a nice rail voltage out of "polluted" mains; b) a small inductor is ultterly ineffective in blocking the pollution; and c) such an ineffective inductor does the power supply no harm.
Now, let's up the size of the inductor to 10mh - which is about the typical inductance of a medium power transformer's primary winding.
Again, here is the waveform.
A few things of interest:
a) the conduction period for the rectifier has greatly been extended, and the peak current greatly reduced. the repeatitive peak current is about 10amp through the rectifier, and the rectifier is conducting almost during the entire half cycle. This is due to the fact that the inductor is essentially storing energy during the half cycle and gradually releasing it to load through the rectifier.
This is all good as it reduces EMI radiation.
b) the rail voltage has greatly been reduced as well: because of the low peak current (10amp vs. 50amp when no power conditioner is used), there is less energy being sent to the capacitor and thus lower rail voltage: at a pultry 20vdc, about 50% lower. This is the issue we discussed earlier: the inductor is choking the power supply to death. or the current limiting others have talked about.
c) the larger inductor does a wonderful job at cleaning up the pollution: look at how clean the voltage on the secondary is during the half cycle when the rectifier is conducting.
Unfortunately, it is the "cleaning" that also killed the power supply's ability to provide the correct rail voltage.
Hopefully, you will conclude by now that a) you don't need a power conditioner for your power supply to work; and b) for an inductor-based power conditioner to be effective at cleaning up the mains, it has to have a negative impact on your power supply.
