XS3 output current?


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 :frowning:

Does anyone know where to look up the Naim output current?

Update: using Flatcap 2X, not XS :slight_smile:

From the Naim spec sheet on the XS3:

Speaker Outputs
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.

(Gosh I hope I did the algebra correctly here… )


Hifi News review on Naim’s product page includes some lab tests. Their answer is max 8.4A.
What’s driving question?

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