beppe61 said:
Dear Sir,
If an amp can deliver continuously let's say 400W on a 4 ohm load (from 20 to 20.000 Hz) it implies that it can deliver surely 10A RMS that become about 14A peak.
Is it a correct assumption ?
beppe
I would like to answer this part of your question and I hope you don't mind. Firstly, your example of 10A rms, at 400W into 4 ohms is true, but only if the 4 ohm load is purely resistive. If it is a 4 ohm impedance of highly inductive nature the current would be much higher.
Secondly, when manufacturers such as HK who provides a high peak current of +/- 75A they are most likely not talking about the same peak (=1.414XRMS) that you were talking about. I believe they are still talking about RMS values but the amplifier could deliver that kind of high current (again, still RMS) for a short duration. Too bad, even HK who seems to enjoy bragging about their high instantaneous current capability do not specify the maximum duration. It could simply be for a microsecond, just for argument sake.
In summary, the 14A peak vs. 10A RMS you referred to is simply a mathematical relationship between RMS and Peak values for a pure sine wave, whereas the peak of very high values that some manufacturers like to talk about are really instantaneous RMS values. In your example, if the amplifier can deliver 10A RMS continuously, then it must deliever 14.14A Peak continuously if the current waveform is sinuisoidal. It is mathematical, you cannot have one without the other.