Help me with the electrical theory here. Won't the circuit continue to provide all the power that the equipment draws until the breaker trips? If the MPS-1 tries to draw 32 amps on a 15 amp circuit, it will trip. If it hasn't tripped, the MPS hasn't tried to draw more than 15 amps. In fact, the circuit with all other equipment hasn't been asked for more than 15 amps.
I'm not aware of any "soft clipping" in a household electrical circuit and don't see how it will limit current to an amp without tripping the breaker. Either it will give the amp all the power it asks for or shut down when the amp asks for too much. To my way of thinking, if you haven't tripped the breaker, your system is getting all the current
it requires. Am I wrong?
Let me make the following points.
1. Circuit breaker trip characteristics:
If your amp and other equipment draw a total current in excess of 15 amps, it may or may not trip the 15 amp circuit breaker. Circuit breakers could have either thermal, magnetic, or thermo magnetic tripping characteristics. In general, magnetic tripping occurs at several times over the rated current in order to allow for transformer inrush (if you turn on a 200WX2 or higher power amp that has a large power supply in it, your lights will dim for a split second due to transformer inrush currents) currents, motor start up currents and other forms of instantaneous peak current conditions. Thermo trips are based on overcurrents that sustain for a period of time because the trip element, e.g. a heater element such as a bi-metal strip reacts to the heat generated by the current so it is dependent not only on the magnitude of the current but also the duration.
2. Limitations of a 15A circuit
In general a 15A circuit is limited mainly by the wire size, typically 14 ga. The more current you draw and the longer run the wire is from the breaker panel, the more voltage drop you will get at the load (your amp). You can search and find a voltage drop table that tells you how many volts/ft drop you can expect from a particular type/make of 14 ga copper wire. If you want to calculate it, voltage drop=Current (in amps) X impedance/ft of the cable in ohms X the length of the cable. As explain in 1), a 15A circuit can deliver much higher than 15A without tripping the breaker as long as the duration for the overload is short. On the other hand, if you amp try to draw say 50A for 10 milliseconds, the breaker will not trip but the voltage drop during that 30 millisecond could be quite high, say 40 volts, then you end up with 80 volts at the amp and that's what limit the current hence power draw by your amp.
3) Display only shows 2.5A
It is possible that your display is not capable of indicating peak instantaneous currents that last only micro or milliseconds. Assuming a typical power factor of 0.7, 2.5AX120X0.7=210W. And further assume that the amp has an overall efficiency of 50%, the amp will output 210WX0.5=110W. If you amp draws 2.5A from the outlet on a continuous basis, it should be playing very loud. For example, 90 dB/W/M speakers will yield 84 dB (free field condition, could be much higher/louder in room) from 2 meters way with only 1W, or 93 dB with only 8 watts. So do not expect to see currents that approach 15A on continuous basis but only on instantaneous basis. You may see it that high in pure direct mode when your amp cannot get help from the sub and has to provide the high instantaneous current demand when that bass drum hits or those explosions in movies.
I should also mention that it also depends on whether the display measures/indicates R.M.S., average, or peak values.
