Naim NAPS 555 DR Reference Power Supply (open box)

The Naim NAPS 555 DR is Naim's reference external power supply, engineered to provide the exceptionally stable, low-noise power required by the company's highest-performance source components.

Power supply design has always been fundamental to Naim's approach to high-end audio. Rather than treating power as a secondary consideration, Naim designs its reference components around the belief that cleaner, more stable electrical power allows the audio circuitry to perform closer to its full potential.

The NAPS 555 DR is the ultimate expression of that philosophy.

Featuring a massive transformer, seven regulated supply voltages, Naim's Discrete Regulator (DR) technology, extensive mechanical isolation, and a dedicated low-resonance chassis, the NAPS 555 DR is designed to improve the performance of compatible Naim source components by providing an exceptionally clean electrical foundation.

The Reference Power Supply for the ND 555

The NAPS 555 DR is the required external power supply for the Naim ND 555 Reference Network Player.

Unlike conventional source components, the ND 555 does not contain its own mains power supply. Naim deliberately moves that function into the separate NAPS 555 DR chassis, keeping the large transformer and associated electromagnetic interference physically separated from the ND 555's sensitive digital and analog circuitry.

One NAPS 555 DR is required to operate the ND 555.

For the ultimate ND 555 configuration, Naim allows the use of two NAPS 555 DR power supplies, providing separate external power supplies for its digital and analog sections.

Why the Power Supply Matters

In a reference audio system, power isn't simply about turning the component on.

Noise and instability in a power supply can affect the sensitive circuitry responsible for digital processing, clocking, digital-to-analog conversion, and analog output.

Naim's approach is to address the problem at its source.

The NAPS 555 DR provides multiple independently regulated power rails rather than asking different circuits to share a conventional supply. Its transformer uses five separate windings feeding seven regulated supply voltages, allowing different sections of a compatible Naim component to receive dedicated power.

The objective is a quieter electrical environment and more stable operating conditions for the audio circuitry.

Naim Discrete Regulator Technology

The DR in NAPS 555 DR stands for Discrete Regulator.

Rather than relying solely on conventional integrated voltage regulators, Naim developed its own discrete regulation architecture to achieve extremely stable, low-noise power.

The DR version also incorporates refinements to internal layout, wire routing, and mechanical decoupling as part of Naim's effort to further reduce unwanted noise and interference.

At this level, seemingly small details matter.

The power supply is part of the audio engineering.

A Massive Transformer

At the heart of the NAPS 555 DR is a substantial transformer that Naim specifies as 40% larger than the transformer used in the XPS.

The transformer incorporates five separate windings supplying the unit's seven regulated voltage rails.

It's an unusually elaborate approach to powering a source component, but that's exactly the point.

The NAPS 555 DR isn't designed simply to provide enough electricity for a component to operate.

It's designed to provide that power with the stability and low noise expected from Naim's reference electronics.

Mechanical Isolation Matters Too

Electrical noise isn't Naim's only concern.

The NAPS 555 DR uses a low-resonance enclosure with isolating feet, while careful mechanical decoupling is used internally to help manage vibration from the large transformer.

Separating the power supply into its own chassis provides another important advantage: the mechanical activity associated with the transformer is physically removed from the sensitive source component it powers.

It's the same fundamental philosophy seen throughout Naim's reference separates:

Separate the functions that can interfere with one another and optimize each for its specific job.

More Than an ND 555 Power Supply

While the NAPS 555 DR is the proper—and required—power supply for the ND 555, its usefulness extends beyond Naim's flagship network player.

Naim lists the NAPS 555 DR as compatible with several of its source components, including:

• Naim ND 555
• Naim NDS
• Naim NDX
• Naim NDX 2
• Naim HDX
• Naim DAC
• Naim CDX2
• Naim CD555

Compatibility and required connection cables can vary by component, so the exact system configuration should be confirmed before installation.

A Serious Upgrade for the NDX 2

The NDX 2 is particularly interesting because it can operate using its internal power supply but also supports an external Naim power-supply upgrade.

Naim currently lists the NAPS 555 DR as a compatible external power supply for the NDX 2, providing an upgrade path for owners who want to take the performance of their existing network player considerably further.

That's different from the ND 555, where the NAPS 555 DR isn't an upgrade—it is required for operation.

Naim NAPS 555 DR Specifications

Type: Reference External Power Supply
Regulation: Naim Discrete Regulator (DR) technology
Regulated Supply Voltages: 7
Transformer Windings: 5 independent windings
Transformer: Approximately 40% larger than Naim XPS transformer
Chassis: Low-resonance construction with isolating feet
Finish: Brushed and anodized aluminum

Dimensions

17.01" W x 3.43" H x 12.36" D
(432 x 87 x 314 mm)

Weight

34.6 lbs.
(15.7 kg)

Mains Supply

115V or 230V, 50/60Hz depending on market version

Off-Mode Power Consumption: Less than 0.3W

Included

The NAPS 555 DR is supplied with a Naim Power-Line mains cable as standard. Required interconnects and Burndy cables can depend on the Naim component and system configuration with which the power supply will be used.

The Grid's Take on the NAPS 555 DR

The NAPS 555 DR is one of those products that makes Naim's design philosophy much easier to understand.

Most manufacturers would never consider building a 35-pound external power supply for a source component.

Naim did.

Five transformer windings. Seven regulated supply voltages. Discrete regulation. Mechanical isolation. A transformer significantly larger than the one found in the XPS. And an entire chassis dedicated to keeping that power-supply hardware away from the sensitive electronics it's feeding.

For the ND 555, it's essential: you need at least one NAPS 555 DR to operate the player.

For compatible components such as the NDX 2, it's an opportunity to take an already excellent source further.

And for the ultimate ND 555 system, adding a second NAPS 555 DR allows the digital and analog sections of the player to receive separate external power supplies.

That's an extreme approach to power supply design.

But reference HiFi has never really been about doing things halfway.

At The Grid HiFi & Home Theater, we can help determine the correct NAPS 555 DR configuration, cables, and system setup for your compatible Naim source component.