Estimate an amplifier’s voltage and current limits using its power specifications.
How To Use
For a particular amplifier, enter its RMS power into a given load. This calculator will return the maximum voltage and current required to deliver that power, assuming a perfect sine signal. A typical Ohm’s law calculator will return different numbers by an order of 3dB, because it will assume DC rather than sine output.
Example
For instance, assume you want to know the maximum voltage that the Schiit Magni Heresy headphone amplifier can output. The amplifier advertises 215mW into 600Ω, its highest impedance listed load. Plugging these values into the calculator returns 16V maximum. Since the amplifier has ±16V power rails and the OPA1688 used by the Magni Heresy is a rail-to-rail device, this result is expected.
On the other hand, assume you want to know the maximum current output of the JDS Atom headphone amplifier. The amplifier advertises 1W into 32Ω, its lowest impedance listed load. Plugging these values into the calculator returns 250mA maximum. Since the amplifier uses an LME49600 buffer, which has a 250mA current rating, as its output device, this result is expected.