Why? Well, unbox the 152 XS pre-amp and you'll see there's no power socket. Touch the vast array of inputs on the rear and there's a slight wobble, as if someone ran out of steam when tightening the screws in the circuit board. This duo looks understated and unassuming, but unfinished? Not quite.
The reason it doesn't feel rigid is that Naim uses a floating circuit board to help isolate the most sensitive sections of the amp from outside vibrations.
The lack of a power socket stems from the fact that the pre-amp is powered via a separate power supply in the power amp. The current is fed through a four-pin DIN lead, which also carries the signal from pre to power.
This arrangement also allows you to upgrade the pre-amp by connecting it directly to one of Naim's optional power supplies (such as the £675 Flat-Cap XS).
More after the break
The flexibility of this pair doesn't stop there. The 152 XS also gives you the option of using either standard RCA phono inputs or Naim's DIN connection.
Sonically truthful performer This pre/power combo conveys the musical message of any given track with aplomb and sincerity. The dramatic tone of 160 BPM is pushed hard and drives along at a rate of knots.
The Naim does a superb job of drawing out the framework of a piece of music and defining the leading edge of every note with real confidence. This allows the listener to worry less about what the music is doing and just allow them to take in the essence of the track.
Naim's own speaker cable helps add some meat to the bones of the music, although the trade off is a slight loss of clarity and insight.
Heard in isolation, the level of detail from the Naim is very good, but compared to its peers, you don't quite get the subtle nuances.
The Naim duo doesn't sound dynamically persuasive either: Jay-Z's Already Home doesn't rise and fall in a way that truly convinces.
Overall, the NAC 152 XS/NAP 155 XS is a talented and well-thought-out duo that has many talents. It just lacks the polish and finesse of the top amps around.