The Matrix Audio NA-1 occupies an interesting position in the company's lineup: a dedicated reference headphone amplifier that also functions as a capable analog preamplifier. Where much of the current market chases all in one convergence, cramming a DAC, streamer, and amplifier into a single box, the NA-1 takes the opposite view. It commits to being a purpose built analog device, one whose entire signal path exists to serve a pair of headphones or a downstream power amplifier. For the experienced listener, that focus is the point. This deep dive examines how the NA-1 is built, how its circuits behave, and precisely how it fits into a serious system.
What kind of device is the NA-1 at its core?
The NA-1 is a reference headphone amplifier with integrated preamplifier functionality. That definition matters because it frames every design decision inside the chassis. Rather than dedicating board space and budget to digital conversion, the NA-1 assumes you already own a quality source or DAC and want the cleanest possible amplification stage between that source and your transducers. The result is a device whose analog section does not compete for power or shielding with a busy digital subsystem, which is a recurring theme when you evaluate how it performs in practice.
Why does the NA-1 use a fully balanced analog architecture?
The NA-1 employs a fully balanced analog architecture, meaning the signal is carried as two mirror image polarities from input to output rather than referenced to a single ground. In a fully balanced topology, each channel runs as a differential pair, so any noise that couples equally onto both conductors is rejected at the output when the two halves are recombined. This common mode rejection is the practical benefit audiophiles chase, but the deeper advantage is symmetry: matched positive and negative signal paths tend to cancel even order distortion products and keep the reference potential stable under the demanding, low impedance loads that headphones present. It also means the amplifier is architecturally native to balanced headphone connections rather than deriving them from a single ended core.
Amplification and Volume Control
How does the NA-1 handle volume adjustment?
The NA-1 uses a precision electronic volume control rather than a traditional analog potentiometer. An electronic volume stage typically operates by switching precisely matched resistor networks or by using a dedicated volume control integrated circuit, adjusting gain in defined steps under microcontroller supervision. The audible payoff is channel matching: a conventional carbon or conductive plastic pot can drift several tenths of a decibel between left and right, especially at low listening levels, which smears the stereo image. A precision electronic implementation holds both channels to the same attenuation value at every step, so imaging stays locked and low volume listening remains centered. In a fully balanced device this matters even more, because the volume stage has to track four signal legs, not two, and any imbalance between them would degrade the common mode rejection the whole topology depends on.
Why does electronic volume control suit a balanced headphone amplifier specifically?
Electronic volume control suits the NA-1 because it preserves the integrity of the differential signal across the entire attenuation range. When you attenuate a balanced signal, you need the positive and negative legs to stay identical in level and phase; otherwise the differential pair becomes unbalanced and you lose the noise rejection benefit precisely when you want it, at quiet passages. A precision electronic stage applies the same digitally defined attenuation to each leg, keeping the balance intact from full output down to a whisper. This is one of those design choices that looks like a convenience feature on a spec sheet but is actually structural to how the amplifier meets its performance goals.
Connectivity: Inputs
What line inputs does the NA-1 provide?
The NA-1 offers one balanced XLR line input and two single ended RCA line inputs. That combination is deliberate and generous for a headphone amplifier. The single XLR input lets you connect a balanced source, most obviously a Matrix Audio DAC with balanced outputs, and carry that fully differential signal straight into the amplifier's native balanced architecture without any conversion. The two RCA inputs then accommodate additional single ended sources, so you might run a balanced DAC on the XLR input and keep two more components, perhaps a second source or an analog device, permanently connected on the RCA jacks.
How should you think about mixing balanced and single ended sources?
You should connect your most capable, ideally balanced source to the XLR input to preserve the differential signal path end to end. When a single ended source arrives on one of the RCA inputs, the amplifier's balanced architecture has to derive the complementary phase internally, which is entirely normal but means the signal does not enter as a fully formed differential pair. For that reason, if you own a source with both balanced and single ended outputs, favor the XLR connection. The three inputs together give you flexible source switching without constantly reaching behind the chassis to swap cables, which is exactly what a hub device in a headphone system should do.
Connectivity: Headphone Outputs
What headphone connections are available on the front panel?
The NA-1 provides three headphone outputs: a 4 pin XLR balanced output, a 4.4mm balanced output, and a 6.35mm single ended output. This trio covers essentially the entire modern headphone landscape. The 4 pin XLR is the long standing standard for balanced desktop headphone cables, the 4.4mm Pentaconn connector has become the prevailing balanced standard for portable and newer cables, and the 6.35mm quarter inch jack remains the universal single ended termination that ships with most full size headphones.
How do the balanced outputs differ from the single ended output in practice?
The two balanced outputs, 4 pin XLR and 4.4mm, deliver the amplifier's fully differential signal directly to headphones wired for balanced operation, while the 6.35mm output presents a conventional single ended feed. In a fully balanced amplifier, the balanced outputs drive each earcup with its own dedicated positive and negative amplifier legs, keeping the left and right grounds isolated from one another. That ground separation reduces crosstalk between channels and lets the amplifier deliver its full differential voltage swing into the headphone. The 6.35mm output shares a common ground between channels, which is perfectly transparent for the vast majority of headphones but does not exploit the balanced topology. Choose the connector that matches your headphone cable, and if your headphones support balanced termination, one of the two balanced jacks will let the NA-1 work the way it was designed to.
Why offer both 4 pin XLR and 4.4mm balanced jacks?
The NA-1 includes both balanced connectors so you never have to buy an adapter to match your existing cables. Because 4 pin XLR and 4.4mm each dominate a different part of the market, providing both means a listener with a desktop cable terminated in 4 pin XLR and a portable oriented cable terminated in 4.4mm can use either without compromise. Electrically both jacks are fed from the same balanced output stage, so there is no performance hierarchy between them; the choice is purely about which plug your cable carries.
Connectivity: Preamp Outputs
Can the NA-1 drive a power amplifier or active speakers?
Yes, the NA-1 includes both a balanced XLR pre-out and a single ended RCA pre-out, letting it function as the analog preamplifier at the center of a two channel system. The preamp outputs pass the volume controlled signal downstream, so the NA-1's precision electronic volume control becomes the master level control for a connected power amplifier or a pair of active monitors. The balanced XLR pre-out is the one to use when your power amplifier or active speakers accept XLR, because it maintains the differential signal path all the way to the next component; the RCA pre-out serves single ended amplifiers and powered speakers that expect an unbalanced feed.
How does the preamp function coexist with headphone use?
The preamp outputs and headphone outputs share the same volume controlled analog stage, so the NA-1 acts as a single hub whether you are listening on headphones or through speakers. This dual role is genuinely useful: a listener can keep a balanced DAC on the XLR input, connect active speakers or a power amplifier to the pre-out, and switch between near field headphone listening and room listening from one device with one volume control and one source selection. It removes the need for a separate preamplifier in a headphone centric system that occasionally wants speakers.
Chassis, Power, and Construction
What is the chassis made of and why does it matter?
The NA-1 uses aluminum construction throughout. Aluminum is the material of choice for high quality audio chassis because it is non magnetic, which prevents the enclosure from interacting with magnetic fields inside the device, and because it is an effective electromagnetic shield that helps keep external interference out of the sensitive low level analog stages. A rigid aluminum enclosure also provides mechanical stability, resisting vibration and giving the internal circuit boards a solid reference. For a device whose entire value proposition is a clean, low noise analog path, the shielding and rigidity of an aluminum chassis are not cosmetic considerations.
Why does the power supply matter so much in a device like this?
A clean, stable power supply is the foundation of any low noise analog amplifier, because the amplifier can only be as quiet as the power feeding it. Every audio circuit works by modulating a supply voltage, so any noise or ripple riding on that supply can leak directly into the output signal. In a fully balanced design, well regulated supply rails also help the positive and negative legs behave identically, preserving the symmetry the topology depends on. This is exactly why keeping digital conversion out of the box pays dividends: without a busy digital subsystem generating switching noise inside the same enclosure, the analog stages face a quieter electrical environment from the start.
Interpreting Performance and System Fit
What does the fully balanced, DAC free approach mean for measured performance?
A fully balanced architecture with a dedicated analog focus generally translates to strong noise rejection and clean channel separation, the two behaviors that most directly shape how a headphone amplifier sounds. Common mode rejection in a balanced design suppresses noise picked up on interconnects and shared grounds, which tends to show up as a low noise floor and excellent left to right channel isolation. Balanced headphone drive, with its separated grounds, further reduces the crosstalk that can blur imaging. When you pair that with a precision electronic volume control that holds channel balance at every step, the practical outcome is a stable, well defined stereo image that does not collapse or wander at low listening levels.
Who is the NA-1 built for?
The NA-1 is built for the listener who already owns a serious source or DAC and wants a reference grade analog amplifier that can also anchor a two channel system. If you have invested in a Matrix Audio DAC with balanced outputs, the NA-1 accepts that signal on its XLR input, keeps it fully balanced through amplification, and hands it to your headphones on the balanced 4 pin XLR or 4.4mm outputs or to a power amplifier on the balanced pre-out. It is a device for people who value focus over feature count, and who understand that a purpose built analog stage in a well shielded aluminum chassis is a meaningful thing to own.
