Audio T Verdict
The Naim NAC 332 is the analogue control centre of the 300 Series. It combines eight physical line inputs, balanced and unbalanced preamplifier outputs, a powerful 6.35mm headphone stage and flexible input configuration within a full-width New Classic chassis.
This is a preamplifier, so it requires a separate power amplifier and loudspeakers. It does not contain network streaming, digital audio inputs, a DAC or a built-in phono stage. Vinyl playback requires a suitable external phono preamplifier, with the powered 8-pin DIN designed to support the Naim NVC TT directly.
The NAC 332 operates from its internal power supply as supplied and can later be upgraded with an NPX 300. Its broad socket choice is useful, but cable selection, input assignment, power-amplifier compatibility and correct placement should be planned as a complete system.
Naim NAC 332 Preamplifier
The NAC 332 is Naim's dedicated 300 Series analogue preamplifier. Discrete transistor audio stages, balanced Class A input circuitry and a relay-switched fixed-resistor volume architecture are combined with modern configuration and system-control functions.
Its eight physical inputs cover balanced XLR, unbalanced RCA and Naim DIN sources. Six named front-panel and remote-control buttons can be assigned to any six of those sockets, allowing the interface to reflect the connected system rather than a fixed rear-panel layout.
Designed For
- High-performance separates systems requiring an analogue preamplifier
- Balanced XLR, RCA and Naim DIN source components
- Naim NSS 333 and NAP 350 system partnerships
- Compatible stereo or mono power amplifiers
- Headphones using a 6.35mm plug
- Optional NVC TT and NPX 300 upgrades
- Systems needing configurable input sensitivity and AV fixed gain
Important Limitations
- A separate power amplifier and loudspeakers are required
- No network streamer, DAC or digital audio inputs are built in
- No MM or MC phono stage is built in
- Micro USB is for service updates, not music playback
- Remote optical sockets carry control data, not audio
- Only six of eight physical inputs have direct selection buttons at one time
- Correctly wired cables are required for legacy Naim power amplifiers
Eight Physical Analogue Inputs
The rear panel provides eight stereo line-input positions:
- Two balanced XLR input pairs
- Three unbalanced RCA input pairs
- Two 5-pin DIN inputs
- One powered 8-pin DIN input, also compatible with a 5-pin DIN connection
The XLR inputs have a published 100kO input impedance, while the DIN and RCA inputs are 47kO. All are specified for 2.2V typical source level and up to 9.5Vrms maximum input.
Analogue Sources Only
The XLR, RCA and DIN sockets accept analogue line-level signals. Digital sources must include their own DAC or connect through a separate digital-to-analogue converter. The Micro USB and Mini-TOSLINK-format control connections are not digital-audio inputs.
Six Assignable Source Buttons
Stream, Phono, CD, Tuner, AV and AUX buttons provide direct source selection from the front panel and ZigBee remote. Any combination of six of the eight physical inputs can be mapped to these buttons.
Factory assignments include XLR input 1 for AUX, RCA inputs 3 and 4 for Tuner and AV, powered 8-pin DIN input 6 for Phono, and 5-pin DIN inputs 7 and 8 for Stream and CD. These labels can be reassigned during setup.
Input Trim, AV Fixed Gain and Volume Limits
Each selected input can be trimmed from -10dB to +10dB, helping sources with different output levels produce more consistent listening volume. Input sensitivity presets and button mapping allow the installation to be tailored without changing the source components.
The AV input can be configured for fixed or unity gain when integrating a compatible home-cinema processor whose own volume control must govern the front channels. This bypasses normal NAC 332 volume adjustment for that input and should be configured carefully.
A maximum-volume function can restrict accidental high output levels. Separate limits can be set for the main preamplifier output and headphone output.
Fixed-Resistor Volume Architecture
The NAC 332 uses a volume-control architecture derived from the Statement preamplifier. Reed relays select fixed through-hole resistors, while the front-panel control uses a fly-by-wire optical encoder and precision bearing rather than passing the audio signal through a conventional rotary potentiometer.
Relay input switching, discrete transistor buffers and separate control circuitry are used to protect the analogue signal path. Naim also galvanically isolates the control and audio sections.
Balanced XLR and RCA Preamplifier Outputs
The primary output is one balanced XLR pair, rated to 10Vrms maximum. It suits compatible balanced power amplifiers, including the Naim NAP 250 and the mono NAP 350 pair with the appropriate cables.
A second unbalanced RCA output pair is also rated to 10Vrms maximum and can support compatible power amplifiers, bi-amplification or a subwoofer. The rear-panel RCA output switch must be set to On when this connection is required.
Legacy Naim power amplifiers without balanced inputs need correctly wired cables. The two XLR signal leads and automation cables used with a pair of NAP 350 amplifiers are supplied with the NAP 350 units, not with the NAC 332.
Dedicated Headphone Amplifier
A front-panel 6.35mm socket is driven by a discrete transistor Class A and Class AB headphone amplifier rated at 1.5W into 16O. It is intended for conventional wired headphones with a compatible plug and load.
Inserting headphones mutes the main preamplifier outputs. Headphone listening has its own remembered volume setting, so removing the plug restores the last speaker-output volume rather than carrying over the headphone level.
External Phono Stage Support
The NAC 332 does not contain an MM or MC phono stage. A turntable therefore connects through a compatible external phono preamplifier.
Input 6 uses an 8-pin DIN socket that accepts a normal 5-pin DIN line connection and also provides positive and negative 18V rails for compatible external phono stages. It can power the Naim NVC TT directly through the correct cable, without requiring the NVC TT's separate NPX TT supply.
DIN Recording Output
Input 8 is a 5-pin DIN socket that also carries a line-level output mirroring the currently selected source. This can serve a compatible recording device or another suitable line-level destination.
If Input 8 itself is selected, the connected source is mirrored at the same socket. Avoid any connection arrangement that returns that output to the selected source and creates a feedback loop.
Internal Power Supply as Standard
The NAC 332 is fully operational without an external supply. It contains a linear audio power supply based around a substantial toroidal transformer, together with a separate efficient supply supporting its low-consumption standby function.
Two supplied link plugs must be installed in the power-supply upgrade sockets when the internal supply is used. The supplied Power-Line Lite connects the NAC 332 directly to the mains in this configuration.
Optional NPX 300 Upgrade
The optional NPX 300 can power the NAC 332 through two Burndy cables, one serving the analogue supply connection and the other the digital or control supply connection. The two link plugs are removed before those cables are fitted.
Remove the NAC 332 Mains Lead When Using NPX 300
When an NPX 300 is installed, the NAC 332 must not remain connected directly to the mains. Its mains lead is removed, and power is supplied by the NPX 300 through both Burndy connections. The complete system must be switched off before the change is made.
ZigBee Remote and System Communication
The supplied bi-directional ZigBee remote does not require direct line of sight. Its illuminated volume indication follows changes made at the preamplifier, and the handset provides source, mute, standby, volume and brightness control.
The NAC 332 can communicate wirelessly with a compatible NSS 333. Within a compatible connected Naim system, the Focal and Naim app can contribute to overall source and system control.
Optical System Automation
One Remote In and two Remote Out sockets accept 3.5mm electrical control connections or Mini-TOSLINK optical automation cables. With compatible products, these links can synchronise standby state and logo brightness.
A matching NSS 333 and NAC 332 communicate through ZigBee, while the NAC 332 Remote Out sockets can control compatible NAP 250 or NAP 350 power amplifiers. These sockets carry automation commands, not music signals.
Power Modes
Typical operating consumption is 20W. Standard standby uses less than 0.5W, while network standby is specified below 2W. The rear-panel Auto Standby setting places the unit into standby after no more than 20 minutes without activity.
Instant On keeps the audio circuitry powered while allowing the front logo to be extinguished. This increases consumption compared with normal standby, so the appropriate mode depends on listening priorities and energy use.
Placement and Cable Planning
The NAC 332 weighs 11kg and needs a stable, ventilated equipment support. Naim recommends a dedicated hi-fi rack and advises against stacking products directly on one another. Position the preamplifier above power amplifiers where practical.
Keep large power supplies and power amplifiers away from sensitive source and preamplifier components to reduce the risk of hum. Allow the XLR, DIN, RCA and Burndy cables to follow relaxed routes without tight bends or strain at the sockets.
Signal Grounding
A rear-panel signal-ground switch provides Default and Ground positions. The correct setting depends on whether the system's primary source already connects signal ground to mains earth. Incorrect earthing can create hum, so Audio T should be consulted if the primary grounding point is uncertain.
Supplied Accessories
The box contains the NAC 332, bi-directional remote control, two power-supply link plugs, Power-Line Lite mains lead, cleaning cloth and documentation pack. Source interconnects and power-amplifier signal cables depend on the chosen system and are not listed as NAC 332 accessories.
Key Features
- Dedicated 300 Series analogue preamplifier
- Eight physical analogue line inputs
- Two balanced XLR input pairs
- Three RCA input pairs and three DIN inputs
- Six assignable front-panel source buttons
- Balanced XLR and unbalanced RCA preamplifier outputs
- Powered 8-pin DIN for compatible NVC TT installation
- 1.5W discrete headphone amplifier
- Relay-switched fixed-resistor volume control
- Input trim, AV fixed gain and maximum-volume settings
- Bi-directional ZigBee remote control
- Optional NPX 300 power-supply upgrade
Frequently Asked Questions
Does the NAC 332 drive loudspeakers directly?
No. It is a preamplifier and requires a compatible power amplifier between its XLR or RCA output and the loudspeakers.
Does it include streaming or a DAC?
No. Every source input is analogue. A streamer or digital source must provide a compatible analogue output, either from its own DAC or through a separate converter.
Can a turntable connect directly?
Not by itself. The NAC 332 has no built-in MM or MC phono stage. Use a compatible external phono preamplifier such as the Naim NVC TT, which can receive power from the 8-pin DIN input.
Why are there eight inputs but only six source buttons?
The rear panel has eight physical inputs. Any six can be mapped to the six named front-panel and remote-control buttons, allowing the direct-access layout to match the installed sources.
Can the 8-pin DIN accept a normal 5-pin DIN source?
Yes, Naim specifies the 8-pin socket as compatible with a 5-pin DIN connection. Its additional contacts provide power for compatible external phono stages.
What happens when headphones are connected?
The main preamplifier outputs mute. The NAC 332 recalls a separate headphone volume setting and returns to the previous speaker-output volume when the headphones are removed.
Can the RCA output feed a subwoofer?
It can feed a compatible line-level subwoofer input. The rear-panel RCA output switch must be enabled, and the subwoofer's input sensitivity and cabling should be checked before connection.
Is an NPX 300 required?
No. The NAC 332 is complete with its internal power supply. The NPX 300 is an optional upgrade that replaces the internal mains connection through two Burndy leads.
Does the NAC 332 remain plugged into the mains with NPX 300?
No. Its mains lead and two link plugs are removed when the NPX 300 is connected. The NAC 332 then receives power through both Burndy cables from the external supply.
Are NAP 350 connection cables supplied with the NAC 332?
No. The matching XLR signal and system-automation leads are supplied with the NAP 350 power amplifiers. Cable requirements differ for other power amplifiers.
What finish is available?
The NAC 332 is supplied in the black anodised aluminium finish used across the New Classic and 300 Series range.
Why Buy From Audio T?
The NAC 332 can support several generations of Naim and non-Naim source and power equipment, but the correct cables and settings vary. Audio T can verify socket wiring, input assignment, power-amplifier compatibility, phono-stage requirements and the most suitable output connection.
Your local store can also demonstrate the internal and NPX 300 power-supply configurations, plan an NSS 333 and NAP 350 system, set up ZigBee and optical automation, and advise on equipment support and cable dressing.
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