Naim NAP 500 Reference Stereo Power Amplifier with 500 PS (open box)

The Naim NAP 500 is the reference stereo power amplifier from Naim's legendary 500 Series, engineered for systems where control, speed, dynamics and musical resolution matter far more than simply chasing the largest wattage number.

Delivering 140 watts per channel into 8 ohms, the NAP 500 was developed over six years and employs an uncompromising two-chassis architecture, separating the amplifier itself from its massive dedicated 500 PS power supply.

The result is one of Naim's most ambitious power amplifier designs—a component built not simply to make loudspeakers play louder, but to exert extraordinary control over them while preserving the timing and musical information coming from the preamplifier.

140 Watts That Doesn't Tell the Whole Story

On paper, the NAP 500 produces 140 watts per channel into 8 ohms.

That's only part of the story.

The amplifier is designed to remain capable of sustained operation into loads as low as 2 ohms, allowing it to maintain control when loudspeaker impedance becomes considerably more demanding.

That's particularly important with reference loudspeakers, where impedance can vary dramatically depending on frequency.

The NAP 500 also offers 700VA of transient output capability, giving it the reserves required to reproduce sudden musical peaks with authority.

The objective isn't simply maximum volume.

It's effortless control.

A Fully Bridged Amplifier Design

The NAP 500 uses a bridged power amplifier configuration engineered to maximize both open- and closed-loop speed.

Each channel incorporates ten stages of local regulation, an unusually elaborate approach designed to provide the amplifier circuitry with extremely stable power exactly where it is required.

That level of regulation reflects one of the central ideas behind Naim engineering:

The quality of the power feeding an audio circuit is inseparable from the performance of the audio circuit itself.

That philosophy becomes even more obvious when you look at the other half of the NAP 500.

The 500 PS: Power Gets Its Own Chassis

The NAP 500 isn't a single-box amplifier.

Its dedicated 500 PS power supply occupies an entirely separate chassis, physically removing the large transformer and associated electromagnetic interference from the sensitive amplifier circuitry.

Inside the 500 PS is an enormous 1,100VA toroidal transformer supplying 12 raw DC power feeds to the amplifier.

Separating the power supply from the amplifier circuitry creates a cleaner electrical environment while allowing Naim to build a considerably more substantial power supply than would normally share the same enclosure.

The NAP 500 and 500 PS aren't an amplifier with an optional upgrade.

They're one amplifier designed as two components.

Designed for Difficult Loudspeakers

Reference loudspeakers can present an amplifier with a far more difficult electrical load than their published specifications might suggest.

Nominal impedance doesn't tell you what happens when impedance drops dramatically during a demanding musical passage.

That's why the NAP 500's ability to operate into 2-ohm loads is important.

Combined with its substantial power supply and transient capability, the amplifier is engineered to maintain its composure when the loudspeaker starts asking for serious current.

Bass control, dynamic contrasts and large musical peaks all depend on the amplifier's ability to respond quickly without losing control.

The NAP 500 was designed for exactly that job.

Speed Matters as Much as Power

A reference power amplifier shouldn't simply be powerful.

It needs to be fast.

The NAP 500's frequency response extends from approximately 1.5Hz to 100kHz at -3dB, giving the amplifier bandwidth far beyond the audible range.

That isn't because anyone needs to listen to a 100kHz tone.

Wide bandwidth and carefully controlled circuit speed contribute to the amplifier's ability to respond quickly to changes in the incoming signal.

For Naim, that ability to follow the timing, attack and decay of music has always been central to the listening experience.

Serious Thermal Management

The NAP 500's substantial black-anodized chassis incorporates its distinctive heatsink structure as part of the amplifier's thermal management system.

Naim also incorporates an intelligent variable-speed fan system that can provide additional cooling when operating conditions require it.

Rather than running continuously, additional cooling is available when necessary, allowing the amplifier to maintain appropriate operating conditions during demanding listening sessions.

At approximately 55 pounds for the amplifier chassis alone, there isn't much about the NAP 500 that's lightweight.

Built in Salisbury

The NAP 500 was developed as the debut product of Naim's reference 500 Series.

Its development required years of work with specialist component suppliers, and construction involves extensive assembly by Naim's experienced technicians in Salisbury, England.

That approach makes sense when you look inside the architecture.

This isn't simply a larger version of a conventional stereo amplifier.

The bridged topology, extensive local regulation, separate 500 PS, custom power architecture and mechanical construction all reflect a product developed without the constraints normally associated with mass-market electronics.

The Natural Partner for the NAC 552

Pair the NAP 500 with the NAC 552 Reference Preamplifier and the logic behind Naim's 500 Series becomes particularly clear.

The NAC 552 separates its sensitive preamplifier circuitry from its dedicated 552 PS.

The NAP 500 does essentially the same thing at the power-amplifier level with the 500 PS.

Source, preamplification and power amplification remain individually optimized, while dedicated power supplies keep large transformers and their associated electrical noise away from the most sensitive audio circuitry.

It's a very Naim way of building a reference system.

And it's about as far removed from an all-in-one amplifier as you can get.

Naim NAP 500 Specifications

Type: Reference Two-Channel Power Amplifier
Configuration: Two chassis — NAP 500 + 500 PS
Power Output: 140 watts per channel into 8 ohms
Minimum Load Impedance: 2 ohms
Transient Capability: 700VA
Frequency Response: -3dB at 1.5Hz and 100kHz
Gain: +30dB
Input Impedance: 18kΩ

Analog Inputs

• 2 x XLR

Speaker Outputs

• Left and Right
• 4mm banana connections

NAP 500 Power Amplifier

Dimensions:
17.01" W x 6.30" H x 14.72" D
(432 x 160 x 374 mm)

Weight:
55.1 lbs. (25 kg)

Finish:
Brushed black-anodized aluminum

500 PS Dedicated Power Supply

At the heart of the NAP 500 system is its dedicated 500 PS external power supply.

The 500 PS features:

• Massive 1,100VA toroidal transformer
• 12 raw DC supplies for the power amplifier
• Separate chassis for improved electromagnetic isolation
• Dedicated connection to the NAP 500
• Power-Line mains cable
• Burndy connection

Mains Supply:
100V, 115V or 230V; 50/60Hz depending on market configuration

What's Included

• Naim NAP 500 Reference Stereo Power Amplifier
• Naim 500 PS Dedicated Power Supply
• Naim Power-Line mains cable
• Burndy connection
• Required factory accessories and documentation

The Grid's Take on the NAP 500

The NAP 500 is a good example of why we don't recommend choosing an amplifier based solely on its wattage rating.

There are amplifiers advertising considerably more than 140 watts per channel.

That's not the point.

The engineering story here is how those 140 watts are delivered.

A separate 1,100VA power supply. Twelve raw DC feeds. Ten stages of local regulation per channel. Bridged amplifier topology. 700VA transient capability. Stability into demanding 2-ohm loads.

Naim has put an extraordinary amount of engineering around the simple task of taking the signal from the preamplifier and controlling a pair of loudspeakers.

That's what makes the NAC 552 + NAP 500 combination so compelling.

The NAC 552 is designed to preserve the signal.

The NAP 500 is designed to take control of the loudspeaker.

Together, they represent one of the defining reference systems in Naim's classic separates lineup.

At The Grid HiFi, we can help configure the NAP 500 as part of a complete reference Naim system, including preamplification, source components, loudspeaker matching, cabling, equipment support and system setup.