Audio T Verdict
The Naim NAP 500 DR is a complete two-box stereo power-amplifier system comprising the NAP 500 amplifier chassis and its dedicated NAP 500 PS power supply. The amplifier cannot operate without that supply and the two required Burndy connections between the enclosures.
Its bridged Class A/B output stages provide 140W per channel into 8O and are specified for prolonged operation into loads down to 2O. Ten local regulation stages per channel, Naim Discrete Regulator technology and a 1,100VA transformer supplying twelve raw DC rails define the system's power architecture.
A separate volume-controlled preamplifier, model-specific signal cables, Naim speaker cable and passive loudspeakers are required. The two enclosures weigh 40.4kg in total and need separate, ventilated equipment-support levels.
Naim NAP 500 DR Power Amplifier with 500 PS
The NAP 500 DR is the stereo power amplifier in Naim's established 500 Series. Its audio circuitry and heat sink occupy the larger NAP 500 enclosure, while the mains transformer and first power-supply stages are isolated in the separate NAP 500 PS.
The package includes both essential enclosures, the dedicated power-supply connections and a Naim Power-Line mains cable. It is not a single self-contained amplifier and the 500 PS is not an optional upgrade.
Designed For
- Reference Naim 500 Series systems
- The Naim NAC 552 with 552 PS DR preamplifier
- Compatible Naim preamplifiers using the correct channel cables
- Carefully matched passive loudspeakers
- Systems requiring sustained low-impedance drive capability
- Dedicated equipment support with separate amplifier and supply levels
- Installations using approved Naim loudspeaker cable and connectors
Important Limitations
- The NAP 500 cannot operate without its dedicated 500 PS
- A separate preamplifier with volume control is required
- The XLR-format inputs use model-specific Classic Naim wiring
- The bridged speaker outputs must never be used as an earth reference
- Only approved Naim speaker cable and supplied connector format should be used
- No streamer, DAC, phono stage or headphone output is built in
- No automatic standby or optical New Classic system automation is provided
A Complete Two-Box System
The NAP 500 amplifier chassis contains both stereo audio channels, their local regulation stages, output devices, protection circuits and variable-speed fan. The NAP 500 PS contains the mains input, power switch, 1,100VA toroidal transformer and first power-supply stages.
Two dedicated Burndy cables carry twelve raw DC supplies from the 500 PS to the amplifier. Both are required, and each must be connected to its matching numbered socket with the complete system switched off and disconnected from mains power.
500 PS Included and Required
This listing is for the NAP 500 DR system, not an amplifier head on its own. The dedicated NAP 500 PS and its required Burndy connections form part of the amplifier design. A 555 PS DR, NPX 300, SuperCap or other Naim supply cannot be substituted.
Correcting the Current Product Copy
The existing page incorrectly begins by naming the NAP 300 DR. This product is the NAP 500 DR: the larger 500 Series stereo amplifier with a 140W-per-channel rating, bridged output stages, ten local regulation stages per channel and a dedicated 500 PS supplying twelve raw DC rails.
Its amplifier chassis is also deeper and taller than the 500 PS. The 520mm depth shown in some summaries is a shipping dimension; the published amplifier depth is approximately 374 to 375mm.
140W per Channel into 8O
The NAP 500 DR provides 140W to each stereo channel into an 8O load. Naim also states that it is capable of prolonged output into a 2O load, with 2O published as the minimum load impedance.
The 700VA transient figure describes short-term system capability rather than continuous output power. Loudspeaker impedance, phase angle, sensitivity, room size and listening level should all be considered when matching a speaker.
Bridged Output Stages
Each stereo channel uses a bridged amplifier configuration. Naim chose this topology to increase open-loop and closed-loop speed, reduce the need for intrusive protection circuitry and keep high loudspeaker drive currents away from the system earth path.
The important installation consequence is that neither the positive nor negative speaker terminal is at earth potential. Both terminals are active parts of the bridged output and must remain isolated from mains earth and from the other channel.
Do Not Ground Either Speaker Terminal
Do not connect an earthed subwoofer high-level input, electrostatic-speaker supply, headphone energiser, test instrument or any other grounded device to the NAP 500 DR speaker outputs unless the manufacturer and Audio T have confirmed a fully floating compatible interface. Use an appropriate preamplifier-level connection wherever possible.
Ten Local Regulation Stages per Channel
Each audio channel incorporates ten stages of local power-supply regulation. The DR version uses Naim's high-power Discrete Regulator technology to reduce supply noise and maintain stable power for the amplifier stages.
The 500 PS transformer provides twelve raw DC supplies through the two Burndy cables. Local regulation within the amplifier chassis then serves individual parts of the two audio channels.
NA009 Output Transistors
The DR specification includes Naim NA009 output transistors developed from the Statement amplifier programme. These devices were created with a specialist semiconductor supplier to combine the required current, power and bandwidth characteristics.
The output-device change was accompanied by DR regulation and revisions to layout and components. An earlier non-DR NAP 500 should not be advertised as a NAP 500 DR unless its factory upgrade status has been verified.
Two XLR-Format Signal Inputs
The NAP 500 chassis has two three-pin XLR-format signal inputs, one for the left channel and one for the right. Input impedance is 18kO and the current product sheet publishes a gain of plus 30dB.
These Classic Naim inputs use model-specific channel wiring rather than the industry-standard true balanced interface found on the current New Classic NAP 250 and NAP 350. The correct preamplifier-to-NAP 500 cables must therefore be selected by source preamplifier and channel.
XLR Socket Does Not Guarantee Balanced Compatibility
Do not connect a generic balanced XLR cable solely because the plug fits. The NAP 500 connection diagram identifies separate channel signal, negative and unused pins. A correctly wired Naim or dealer-approved cable is required for the chosen preamplifier.
Preamplifier Compatibility
The natural 500 Series partner is the NAC 552 with its 552 PS DR. Compatible Naim preamplifiers route their volume-controlled left and right signals to the two NAP 500 inputs through the appropriate DIN-to-XLR or XLR-format channel cables.
A third-party preamplifier may be possible only with a correctly wired adaptor and suitable output level, impedance and earthing arrangement. Never connect a fixed-level source directly to the NAP 500 because there is no volume control in the power amplifier.
Naim Speaker Cable Is Required
Naim's reference manual states that Naim Audio loudspeaker cable should be used with the NAP 500 and warns that unsuitable special cable may damage the amplifier. NACA5 or another Naim-approved speaker cable should be selected for the installation.
Left and right runs should be equal in length, with the cable direction arrows pointing from the amplifier towards the loudspeakers. Classic Naim guidance specifies at least 3.5m per channel and a normal recommended maximum of 20m.
Supplied Naim Speaker Connectors
Custom Naim twin loudspeaker connectors are supplied for the left and right outputs. The reference manual specifically warns against replacing them at the amplifier end with separate individual 4mm plugs.
Both channels must maintain the same positive and negative polarity. Because the amplifier is bridged, no speaker conductor should be joined between channels or connected to chassis or mains earth.
Variable-Speed Cooling and Protection
The NAP 500 uses a distinctive heat sink and variable-speed intelligent fan. Fan speed rises with amplifier dissipation, so the top and bottom ventilation grids must remain completely clear.
If the amplifier reaches approximately 70°C through sustained high output or obstructed airflow, its output is interrupted and the fan runs at full speed until the unit cools. Reduce the preamplifier volume because playback can resume automatically after the protection state clears.
Two Enclosures and 40.4kg
The NAP 500 amplifier measures 160 x 432 x approximately 375mm and weighs 25kg. The NAP 500 PS measures 87 x 432 x 314mm and weighs 15.4kg, giving a combined equipment weight of 40.4kg.
Each enclosure requires its own stable equipment-support level. The taller amplifier needs adequate clearance above and below its ventilation grids, while the 500 PS should be kept away from sensitive source and preamplifier circuitry where the rack layout allows.
Burndy Cable Dressing
Position both enclosures before connecting the two power-supply cables. Align every connector correctly, tighten the locking collars without forcing them and allow the cables to hang in broad natural curves.
Avoid tight bends, tension, contact with walls or pressure from furniture. Do not connect, remove or reseat either Burndy while the 500 PS is connected to mains power.
Mains Power and Switching
Only the NAP 500 PS connects to mains power. Its front-panel button controls the complete two-box amplifier, and the supplied mains lead is a full Naim Power-Line rather than a Power-Line Lite.
Switch on source components, their external supplies and the preamplifier before switching on the NAP 500 DR, with the volume turned down. When making connection changes, switch off at the 500 PS, disconnect from mains power and wait at least one minute.
No Standby or System Automation
The NAP 500 DR follows the established Classic operating arrangement. It does not provide the sub-0.5W automatic standby, music-sensing wake or optical Remote In and Remote Out automation used by New Classic power amplifiers.
The published Classic reference-manual quiescent consumption is 60VA. This is separate from the 700VA transient specification and should not be described as standby consumption.
Supplied Accessories
The complete system includes the NAP 500 DR amplifier, dedicated NAP 500 PS, the required NAP 500 PS Burndy cables, Naim Power-Line mains lead and custom Naim loudspeaker connectors.
Preamplifier signal cables depend on the connected model and should be specified separately. Loudspeaker cables, sources, preamplifier, loudspeakers and equipment support are also separate unless Audio T states otherwise.
Key Features
- Complete NAP 500 DR and dedicated 500 PS two-box system
- Bridged Class A/B stereo output stages
- 140W per channel into 8O
- Specified for prolonged output into 2O loads
- Ten local regulation stages per channel
- Naim high-power Discrete Regulator technology
- 1,100VA toroidal transformer
- Twelve raw DC supplies between power supply and amplifier
- Statement-derived Naim NA009 output transistors
- Variable-speed intelligent cooling fan
- Two dedicated Burndy power-supply connections
- Full Naim Power-Line mains cable supplied
Frequently Asked Questions
Does this listing include the 500 PS power supply?
Yes. The NAP 500 DR is a complete two-box system containing the stereo amplifier and its dedicated NAP 500 PS, together with the required inter-chassis power connections.
Can the amplifier operate without the 500 PS?
No. The amplifier chassis has no independent mains supply. It receives twelve raw DC supplies from the 500 PS through two Burndy cables.
Can I use a 555 PS DR instead?
No. The 555 PS DR is for compatible Naim source components. Only the dedicated NAP 500 PS is designed to power the NAP 500 amplifier.
Are the XLR inputs conventionally balanced?
No. The Classic NAP 500 uses three-pin XLR-format sockets with model-specific single-ended channel wiring. Use the correct Naim or dealer-approved cable for the connected preamplifier.
Why can neither speaker terminal be grounded?
Each channel is bridged, so both positive and negative terminals are driven and neither sits at earth potential. Grounding either terminal can damage the amplifier or connected equipment.
Can I connect a subwoofer to the speaker outputs?
Not unless the complete high-level interface is confirmed as fully floating and compatible with bridged outputs. A suitable preamplifier-level subwoofer connection is normally the safer arrangement.
Does the NAP 500 DR require Naim speaker cable?
Yes. Naim's reference manual specifies Naim Audio loudspeaker cable and the supplied Naim connectors. Equal runs should be at least 3.5m, with 20m the normal recommended maximum.
Does it include speaker cables?
No. Naim speaker connectors are supplied, but suitable equal-length speaker cables and loudspeaker-end terminations are separate.
Does it include preamplifier signal cables?
These depend on the preamplifier and should be specified separately. The left and right NAP 500 inputs require correctly wired model-specific channel cables.
Can the amplifier and power supply be stacked?
No. Both heavy enclosures need separate stable support levels, and the amplifier's top and bottom ventilation grids must remain clear.
What happens if the amplifier becomes too hot?
At approximately 70°C the output is interrupted and the fan runs at full speed until the amplifier cools. Reduce the preamplifier volume because playback can resume when protection clears.
Does the NAP 500 DR have automatic standby?
No. It uses the front-panel power control on the 500 PS and does not provide New Classic optical automation, automatic standby or music-sensing wake.
Why Buy From Audio T?
The NAP 500 DR requires a model-specific preamplifier cable, two correctly routed Burndys, approved speaker cable and careful treatment of its bridged outputs. Audio T can verify the entire signal, power and earth arrangement before installation.
Your local store can also demonstrate the complete two-box amplifier, prepare equal-length NACA5 connections, plan suitable Fraim levels, position the 40.4kg system safely and confirm compatibility with loudspeakers and subwoofers.
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