I have recently purchased the new magneplanar pair of speakers, the sound amazing with my DAC-V1 + XS3 + Flatcap XS, but i am curious what is my system max output current. Couldn’t find the answer in specs or on forum
Does anyone know where to look up the Naim output current?
70W per channel into 8 ohms
100W per channel into 4 ohms
These are max power numbers, and
Power (W) = Voltage (V) x Current (A)
and from Ohm’s Law we have
Voltage (V) = Current (A) x Resistance (ohm)
thus (after some rearranging)
Current = square root (Power / Resistance)
So you can work out the equivalent maximum Currents:
I (8 ohms) = sqrt (70 / 8) = 3 A
I (4 ohms) = sqrt (100 / 4) = 5 A
You can’t say in advance what current is being delivered at any given time, since of course that depends on your volume setting… and the effective resistance of a loudspeaker depends (often strongly) on the frequency, which complicates things further.
As an aside: you can now clearly see that the supply is “current limited”, since the naive current doubles as the resistance is halved (ie going from 8 to 4 ohms) but the XS3 cannot source the anticipated 6 A (140 W), but only the quoted 5 A (100 W)… this is a big differentiator as to why some amplifiers seem “bigger” or “more capable” even when they have the same max power into 8 ohms.