Matrix Audio mini-i Pro 4: An Audiophile Deep Dive

What DAC chip powers the mini-i Pro 4?

The mini-i Pro 4 is built around the ESS ES9038PRO, the flagship converter in ESS Technology's Sabre PRO family. This is the same silicon architecture found in far larger and more ambitious digital front ends, and its presence here signals the design intent of this compact unit. The ES9038PRO uses a 32bit HyperStream II modulator topology paired with ESS's Time Domain Jitter Eliminator. In practical terms, the chip integrates eight internal DAC channels that Matrix Audio can sum in parallel per output phase. Paralleling channels lowers the noise floor and improves linearity because uncorrelated noise from each channel partially cancels while the desired signal adds coherently. The result is a conversion stage with substantial headroom for the analog output and headphone stages that follow.

How high can the PCM and DSD resolution go?

The mini-i Pro 4 decodes PCM up to 32bit / 768kHz and DSD up to DSD512 in native mode. The 768kHz ceiling covers every commercially available PCM file plus any upsampled output you might feed it from a software player or Roon's DSP engine. Native DSD512 handling means the unit passes the one bit stream directly to the converter rather than converting it to PCM first, which preserves the intended signal path for DSD recordings. To reach these rates you generally need the USB input, since the S/PDIF style connections are bandwidth limited by their own specifications. This is worth remembering when planning which source feeds which input.

Does it support MQA?

Yes, the mini-i Pro 4 performs full MQA decoding. Full decoding means the unit handles the complete unfold process internally rather than relying on a software core decoder to do the first unfold before handing off. When you play an MQA file or stream, the DAC executes the entire authentication and rendering chain, which is the intended playback path for that format. For listeners with libraries or streaming subscriptions that include MQA masters, this removes the need for a separate software renderer in the signal chain.

What role does the master clock play?

The mini-i Pro 4 uses a high precision femtosecond crystal oscillator as its master clock, and its job is to time the conversion so precisely that jitter is pushed below audible and measurable significance. Jitter is timing uncertainty in the moment each sample is converted, and it manifests as sidebands and noise around the signal. A femtosecond class oscillator has phase noise low enough that the timing error contributes negligibly to the output. Combined with the ES9038PRO's own jitter elimination stage, the local clock lets the DAC reclock incoming data to its own reference rather than being enslaved to a potentially noisy source clock. This is why USB and network playback can sound as composed as they do on this platform.

Power Supply and Build

How is the power supply designed?

Matrix Audio designs the mini-i Pro 4 around a linear regulated supply topology with multiple independently filtered rails feeding the sensitive analog, digital, and clock sections separately. The reason for separating rails is isolation: digital switching activity generates noise that you do not want coupling into the analog output stage or the clock. By giving the oscillator, the DAC's analog reference, and the output amplifiers their own regulated feeds, each section sees a cleaner, more stable voltage. Clean power directly supports the low noise floor that the measured dynamic range figure reflects, since any ripple or noise on the rails ultimately appears at the output.

What is the chassis made from and why does it matter?

The mini-i Pro 4 uses a machined aluminum enclosure, and the material choice serves both mechanical and electrical purposes. Aluminum provides a rigid, non resonant structure that resists microphonic effects on the internal circuitry and the crystal oscillator. Electrically, the metal chassis forms a shield against external radio frequency and electromagnetic interference, which is increasingly important in a device that includes Wi-Fi radios inside the same box as high resolution analog circuitry. The compact footprint keeps signal traces short, which reduces the opportunity for noise pickup between stages.

Connectivity and System Integration

What digital inputs are available?

The mini-i Pro 4 provides USB, coaxial, optical, and HDMI ARC digital inputs, which is a deliberately broad set for a unit of this size. The USB input is the workhorse for computer audio and is the path that unlocks the full 32bit / 768kHz PCM and DSD512 rates. Coaxial and optical S/PDIF inputs accept CD transports, older streamers, and game consoles, with the practical bandwidth limits of those interfaces applying to sample rate. The standout inclusion is HDMI ARC, which lets the mini-i Pro 4 accept audio directly from a television. That single connector transforms the unit from a desktop DAC into the audio hub of a living room system, drawing sound from a smart TV's apps and connected sources without a separate outboard converter.

Is there an analog input?

Yes, the mini-i Pro 4 includes an RCA line input, which allows an analog source to join the system alongside all the digital feeds. This is useful for integrating a phono stage output, a tuner, or another analog component whose signal you want to route through the mini-i Pro 4's volume control and output stages. The presence of an analog input means the unit can serve as a modest preamplifier and switching center rather than strictly a digital only device, giving it flexibility in a mixed source setup.

What analog outputs does it offer?

The mini-i Pro 4 provides both balanced XLR and single ended RCA analog outputs, and having both lets it drive a wide range of downstream gear. The balanced XLR pair is the preferred connection to a balanced power amplifier or active monitors, since the differential signal rejects common mode noise picked up along the cable run and preserves the full performance of the ES9038PRO's differential architecture. The RCA output serves single ended amplifiers, integrated amps, and equipment that lacks balanced inputs. Because both outputs are available, you can run one to a main system and use the other for a secondary connection, subject to the unit's output configuration.

Which headphone outputs are provided?

The mini-i Pro 4 offers a balanced 4.4mm output and a single ended 6.35mm output on the front panel, covering both major connection conventions for personal listening. The balanced 4.4mm jack delivers a differential drive to headphones equipped with balanced cables, which typically increases available voltage swing and improves channel separation by giving each channel its own return path. The 6.35mm quarter inch jack accommodates the vast majority of full size headphones with standard single ended terminations. Having both means you rarely need an adapter, and you can keep two headphones connected for quick comparison.

How does it connect to a network?

The mini-i Pro 4 connects through both Ethernet and Wi-Fi, giving you a choice between the stability of a wired link and the convenience of wireless placement. A wired Ethernet connection is generally the more robust option for high resolution streaming because it avoids the congestion and interference that can affect wireless in a busy environment. Wi-Fi frees the unit from proximity to a router, which suits a desktop or living room location. Either way, network connectivity is what turns the mini-i Pro 4 into a self contained streamer rather than a DAC that depends on an attached computer.

What streaming services and protocols are supported?

The mini-i Pro 4 is Roon Ready and supports TIDAL, Qobuz, Spotify, DLNA, and AirPlay. Roon Ready certification means it functions as a Roon endpoint with the tight metadata, bit perfect delivery, and multi zone management that Roon users expect. Native TIDAL and Qobuz support lets you stream those high resolution services directly from the control app without a computer in the chain. DLNA opens the door to streaming from a NAS or local media server, while AirPlay provides a quick wireless path from Apple devices. Spotify support covers the most widely used mainstream service. This combination means most listeners can play their preferred source without additional hardware.

How do you control the unit?

The mini-i Pro 4 is controlled through the MA control app and the front panel, so you can operate it from your phone or directly from the device. The MA app manages input selection, volume, filter settings, streaming library browsing, and network configuration from a mobile device, which is the natural way to drive it when it sits across a room. The front panel provides direct access with a display and controls for situations where you prefer hands on operation or want to make a quick change without reaching for a phone. Having both keeps the unit usable in a wide range of placements.

Measured Performance

What does the THD+N figure tell us?

The mini-i Pro 4 specifies THD+N at -121 dB, and this number describes how little the unit adds to the signal in the form of harmonic distortion and noise combined. Expressed as a ratio, -121 dB means the unwanted content sits roughly a million times below the music itself. This is deep enough that the distortion signature of the DAC is well below the threshold of audibility and, in most systems, below the noise contributed by the recording and the room. It reflects the linearity of the paralleled ES9038PRO channels and the care taken in the analog output stage and power supply.

What does the dynamic range specification indicate?

The mini-i Pro 4 specifies a dynamic range of 127 dB, which describes the span between the loudest signal it can output and its residual noise floor. A 127 dB figure indicates an extremely quiet noise floor, which is what allows low level detail, reverb tails, and the space around instruments to emerge without being masked by hiss. This measurement is closely tied to the linear power supply and the clock design, since both power rail noise and jitter would otherwise raise the noise floor and erode this number. For a unit this compact, a 127 dB dynamic range is a strong result and confirms that the flagship converter is being given a supporting circuit worthy of it.

Who is the mini-i Pro 4 for?

The mini-i Pro 4 suits the enthusiast who wants a single compact component to serve as streamer, DAC, preamplifier, and headphone amplifier without stacking multiple boxes. Its combination of the ES9038PRO converter, femtosecond clock, comprehensive digital and analog inputs including HDMI ARC, both balanced and single ended outputs, and full network streaming makes it a genuine system hub. For a desktop rig, a headphone setup, or a compact living room system built around a television, the mini-i Pro 4 consolidates functions that would otherwise require several separate Matrix Audio or third party components into one carefully engineered chassis.