Cambridge Audio has spent decades building a reputation for engineering-led British hi-fi that prioritizes measurable performance and musical honesty over cosmetic flash. The EXA100 sits in the company's EX series, a range that slots above the entry-level offerings and shares design language and internal thinking with the network-focused EXN100. What you get in the EXA100 is a fully integrated stereo amplifier with a serious DAC on board, engineered as a modern hub that can anchor a system built around real amplification rather than convenience-first electronics. The following deep dive walks through the topology, power delivery, build, and connectivity, explaining not just what each element is but why it exists and what it does for the sound.
Amplification and Topology
What amplifier class does the EXA100 use, and why does it matter?
The EXA100 uses a Class AB output stage. Class AB is a deliberate compromise between the low distortion of Class A biasing and the efficiency of Class B, and it remains the workhorse topology for high-quality integrated amplifiers because it delivers the best of both worlds. In practical terms, the output transistors are biased so that both devices conduct together through the critical low-level region where crossover distortion would otherwise appear, then hand off cleanly at higher output swings. The audible benefit is a clean, quiet noise floor at listening levels combined with the headroom to drive dynamic peaks without the heat and inefficiency penalties of a full Class A design. For an enthusiast, this means low distortion where your ears are most sensitive plus real-world drive capability.
How much power does the EXA100 deliver, and what does that tell you?
The EXA100 delivers 100 watts per channel into 8 ohms and 155 watts per channel into 4 ohms. That pairing of numbers is more informative than a single figure because it tells you how the amplifier behaves as speaker impedance drops. An ideal voltage source would double its power when impedance halves, so a perfect 100 watt into 8 ohm amp would produce 200 watts into 4 ohms. The EXA100 climbs to 155 watts, which indicates a robust but not unlimited current delivery. That is a healthy, honest result and reflects a well-specified power supply and output stage that can push meaningful current into moderately demanding loads. In listening terms, it means the amplifier maintains grip and dynamic authority as speaker impedance dips, which is exactly where lesser designs tend to soften and compress.
Why does the toroidal transformer matter?
The toroidal transformer is the heart of the power supply, and it matters because its geometry directly affects noise, efficiency, and dynamic delivery. A toroidal core is wound as a continuous ring rather than stacked laminations, which gives it a tighter magnetic coupling, lower stray magnetic field leakage, and greater efficiency than a conventional EI transformer of similar rating. Lower leakage flux means less hum induced into sensitive audio circuits, which contributes to a quieter background. The tight coupling and larger effective core also mean the transformer can store and release energy quickly, supplying instantaneous current when the music demands a transient. That is what you hear as slam on a kick drum or the sense that the amplifier never runs out of breath on complex passages. Cambridge Audio's choice of a toroidal design here reflects a priority on clean, stiff power delivery feeding the Class AB output stage.
Digital Conversion and Format Support
What DAC does the EXA100 use, and why was it chosen?
The EXA100 uses the ESS Sabre ES9018K2M digital-to-analog converter. This is a well-regarded two-channel chip from the Sabre family, known for a low noise floor, high dynamic range, and ESS's proprietary Hyperstream modulator architecture along with its jitter-reduction system. The reason a chip like this is chosen for an integrated amplifier is that it lets the EXA100 accept and decode high-resolution digital sources internally, so you can feed it a raw digital stream and let a purpose-built converter and analog output stage handle the conversion rather than relying on the source's own DAC. Practically, this centralizes digital playback in one carefully engineered box, which simplifies your system and removes the variable quality of source-device converters from the equation.
What digital formats and sample rates can it handle?
The EXA100 handles USB audio up to 384kHz and 32-bit as well as DSD256, coaxial S/PDIF up to 192kHz and 24-bit, optical TOSLINK up to 96kHz and 24-bit, and HDMI eARC up to 192kHz and 24-bit. The differences between these ceilings are not arbitrary. The USB Type-B input is asynchronous by design and offers the highest limits because it can operate the DAC on its own clock and pull data from the computer, which is why it supports both very high PCM rates and native DSD. Coaxial S/PDIF carries an electrical signal over a 75 ohm connection and typically supports higher rates than optical because it is less bandwidth limited. Optical TOSLINK uses a light pipe that is fully galvanically isolated, breaking ground loops and electrical noise, but its bandwidth caps the practical rate at 96kHz here. Understanding these ceilings lets you route each source to its most capable input.
How does HDMI eARC work on this amplifier?
The HDMI eARC input lets the EXA100 receive audio directly from a television at up to 192kHz and 24-bit over a single cable. eARC, the enhanced Audio Return Channel, is a two-way HDMI feature that allows a TV to send full-resolution stereo audio back down the HDMI link to the amplifier. For a two-channel enthusiast who also watches films and streams from smart TV apps, this is significant because it means your main hi-fi system can double as the television's sound system without downmixing or resorting to a lossy connection. It also supports the convenience of TV remote volume control passing through, which keeps the setup uncluttered.
What does Bluetooth 5.0 with aptX HD add?
Bluetooth 5.0 with aptX HD gives the EXA100 wireless playback from phones, tablets, and computers with a higher-quality codec than standard Bluetooth. aptX HD supports a larger data payload than baseline SBC, which reduces the audible penalty of wireless transmission and preserves more detail and dynamic range from a compatible source device. Bluetooth 5.0 itself brings a more stable connection and better range. It is important to be clear about what this is and is not: it is a convenience wireless input, not a network streaming platform, and its quality still depends on the source device's own codec support.
Connectivity and System Integration
What inputs and outputs does the EXA100 offer?
The EXA100 provides a balanced XLR input, multiple RCA line inputs, coaxial S/PDIF, optical TOSLINK, USB Type-B, HDMI eARC, and Bluetooth 5.0, along with preamp output, subwoofer output, a headphone jack, and two sets of speaker terminals. The balanced XLR input is notable because it accepts a differential signal that carries the audio on two conductors of opposite polarity, allowing common-mode noise picked up along the cable to be rejected at the input. That makes it the preferred connection for a high-quality source with a balanced output, especially over longer cable runs. The two sets of speaker terminals allow biwiring or driving two pairs of speakers, and the preamp and subwoofer outputs let you expand into external power amplification or add a subwoofer for full-range or home-theater duties.
Does the EXA100 have a phono stage or built-in streaming?
No, the EXA100 has no built-in phono stage and no onboard network streaming, offering Bluetooth as its only wireless input. This is a deliberate design decision rather than an oversight. Leaving out a phono stage keeps the sensitive low-level circuitry out of the chassis, and if you run a turntable you would add an external phono preamp into one of the line inputs. For streaming, Cambridge Audio intends the EXA100 to pair with the EXN100 network player, which handles the network audio and platform side while the EXA100 focuses purely on conversion and amplification. This separation of duties is a classic hi-fi approach that isolates noisy digital and network circuitry from the amplification.
What does the headphone jack contribute?
The headphone jack lets you drive a pair of headphones directly from the amplifier without needing a separate headphone amp. Integrating this into the EXA100 means the same clean power supply and DAC feeding the speakers also serve private listening, giving you a coherent sonic signature whether you are on speakers or cans. It also makes the amplifier a complete solution for a desktop or bedroom rig where a standalone headphone amp would be redundant.
Build, Physical Design, and Lineup Position
How is the EXA100 built and how big is it?
The EXA100 measures 115 x 430 x 341 mm (4.5 x 16.9 x 13.4 inches) and weighs 12.8 kg (28.2 lbs). That weight is meaningful for an integrated amplifier of this size because much of the mass comes from the toroidal transformer and the heatsinking required by a Class AB output stage. A heavier chassis with substantial internal metalwork resists vibration and provides the thermal mass to dissipate heat safely, both of which support consistent performance. The relatively compact footprint makes it easy to place on a standard equipment rack or shelf.
What finish is available and where does the EXA100 sit in the range?
The EXA100 comes in a Lunar Grey finish and sits in Cambridge Audio's EX series as its integrated amplifier, designed to partner with the EXN100 network player. Positioned above the brand's entry-level electronics, the EX series represents a step up in build, power supply, and conversion ambition. The EXA100 is best understood as the amplification and DAC anchor of a modular EX system: pair it with the EXN100 for streaming, add a turntable through an external phono stage, and connect a television through eARC, and you have a flexible, high-resolution two-channel core built around honest engineering and clean, capable power delivery.
