Arcam SA45 Streaming Amplifier

Introduction

The Arcam SA45, costing £4500, marks a significant step in Arcam's streaming amplifier evolution, embodying a 'brand redesign' with a fresh aesthetic and enhanced features. This flagship model in the Radia lineup aims to deliver powerful performance coupled with modern connectivity and an improved user experience.

Design and Aesthetics

The SA45 showcases a departure from Arcam's previous conservative styling, adopting a more striking appearance with black casework accented by vibrant yellow flourishes, which extend to the bundled remote control and the Radia app. A key new feature is the large 8.8-inch (224mm) full-colour display, capable of showing album art, chosen input, and internet radio presets, bringing it in line with contemporary high-end audio equipment. Internally, the amplifier features Arcam's fifth-generation Class G amplification, rated at 2x180W into 8 ohms. This refined Class G concept uses a power supply that smoothly tracks the audio level rather than switching abruptly between voltages. The internal construction includes a massive toroidal transformer powering the Class G PSU and amplifier stages, supported by multilayer Printed Circuit Boards (PCBs) that house the network module, HDMI eARC input, ES9027SPro DAC, MM/MC phono stage, line inputs, and isolated preamp outputs.

Connectivity and Digital Capabilities

The SA45 offers comprehensive connectivity options. It includes separate MM and MC phono inputs, three RCA and one balanced XLR analogue line inputs, and preamp outputs (RCA and XLR) for integration with external amplifiers. Digital inputs consist of pairs of optical and coaxial ports, a USB-A for media playback from storage devices, and HDMI eARC. Networking is facilitated by an Ethernet socket, Wi-Fi, and two-way aptX Bluetooth, which also enables connection to Bluetooth headphones. The amplifier's digital audio and streaming platform supports popular services like Qobuz Connect, Tidal Connect, and Spotify Connect, along with Apple AirPlay and Google Cast. Roon certification is noted as pending. File handling supports up to 384kHz/32-bit PCM and DSD512, processed by the ESS ES9027SPro DAC, integrated into a new six-layer board with fully balanced analogue circuitry. A new linear power supply works alongside the Class G amplification, with a switch-mode PSU managing standby operations.

The SA45 incorporates Dirac Live Room Correction, a sophisticated calibration platform that includes a microphone and software for PC/Mac. This system is designed to optimize room acoustics and enhance subwoofer integration, offering detailed adjustments. Analogue signals can bypass the digital processing stages by selecting a 'Direct' playback mode, preserving an all-analogue signal path.

Arcam Radia App Functionality

The dedicated Arcam Radia app, available for iOS and Android, represents an improvement over Arcam's previous MusicLife app, offering a slicker design and more intuitive operation. Its primary functions include music selection and network/Wi-Fi setup. However, it does not provide control over the SA45's input selection, digital filters, Dirac profiles, or other hardware settings. The app's main interface displays icons for Presets, Radio, streaming services (Qobuz Connect, Spotify), UPnP, and USB. A settings page allows for firmware updates, network configuration, and device renaming. For Internet Radio, the app uses the Airable platform, enabling browsing by genre, language, and location, with options to mark stations as favourites and set up six presets. Album artwork is displayed when playing music from streaming services, radio, or local content. Volume adjustment is available via an on-screen slider, as the app does not utilize the smartphone's volume keys.

Sonic Performance and User Experience

The Arcam SA45 is noted for its purposeful and powerful sound signature, delivering substantial 'grunt' with excellent grip and depth in the bass and percussion. This solidity extends throughout the audioband, providing a listening experience with considerable body and heft. The amplifier adopts a crowd-pleasing approach, proving equally suitable for contemporary artists like Taylor Swift as it is for classical composers like Tchaikovsky. It effectively balances sonic elements, creating space for each component within the mix. The Class G amplification provides a noticeable boost in power when confronted by demanding bass passages, giving the impression of shifting into a higher gear. Bass reproduction is consistently praised as weighty, tight, and well-defined. The digital stage is described as focused and detailed, though perhaps not reaching the extreme airy highs of some dedicated digital components. Tonally, the amplifier is generally neutral but remains inviting to listen to. The user experience is enhanced by the remote handset, which features matching yellow accents and offers full control and configuration, although the Radia app remains essential for music streaming. The display, while not a touchscreen, provides clear information from a distance. User settings include choices for digital filters, display illumination, input hiding, balance, and maximum volume. It is noted that there are no specific loading options for the MM/MC phono inputs.

Lab Report Highlights

The Arcam SA45 demonstrates impressive technical performance. Its 5th generation Class G technology effectively reproduces dynamic signals. Power output exceeds the rated 180W/8ohm, reaching 198W into 8 ohms and 323W into 4 ohms. Under dynamic conditions (1kHz/10msec/<1% THD), it delivers 255W into 8 ohms, 475W into 4 ohms, and 805W into 2 ohms. Distortion levels are exceptionally low, measured between 0.0004-0.0009% across its full 180W rated range and even lower at lower output levels. The amplifier features very low noise and a wide 96dB A-wtd S/N ratio. Its frequency response is flat to ±0.17dB from below 1Hz to 75kHz, with a low output impedance. The digital section is equally strong, exhibiting vanishingly low jitter (<5psec) and a high 111dB A-wtd S/N ratio. Distortion in the digital stage is also remarkably low. The choice of four digital filters from the ES9027 SPro DAC influences the frequency response at higher sample rates.

Key Specifications:

Note on Graphs: The original document referenced graphs detailing dynamic power output versus distortion into various speaker loads (8, 4, 2, and 1 ohm) and distortion versus digital signal level. These visualisations are described but not included in the provided text.

Verdict

The Arcam SA45 is presented as a strong representative of Arcam's revitalized hi-fi range and aesthetic rebranding. It is considered their most stylish and feature-rich amplifier to date, offering a thoroughly modern design and execution. Sonically, it is adaptable, handling a wide spectrum of music genres and room acoustics effectively through its Dirac software. The overall performance is highly regarded, positioning the SA45 as a compelling choice in its market segment.