Head-Fi Hero: Astell&Kern ACRO CA1000 redefines the headphone amplifier with digital audio player capabilities

Astell&Kern, the global leader in premium high-resolution audio devices has redefined the headphone amplifier with the introduction of the ACRO CA1000. Expertly combining high-performance amplifiers with digital audio player (DAP) capabilities in an incredibly compact desktop and carriable-friendly form, the powerful ACRO CA1000 delivers the optimal performance from any type of wired headphone. An array of digital/analogue inputs and outputs also ensures the ACRO CA1000 can be at the heart of any hi-fi set-up and become the ultimate system for head-fi fans. This system represents Astell&Kern’s fundamental philosophy of delivering as close to the original sound as possible and enriching the listening experience.

Astell&Kern ACRO CA1000 key features at a glance:

Powerful headphone amplifier with digital audio player capabilities.
Features a four step Gain Level that drives high impedance headphones with a 15Vrms output or below.
Features 3.5mm, 6.35mm unbalanced, and 2.5mm 4.4mm balanced headphone output to handle a wide variety of headphones.
An array of digital/analogue inputs and outputs ensures it can at the heart of any hi-fi set-up.
Onboard ESS ES9068AS Quad-DAC delivers a clear, detailed and balanced sound.
Supports high-resolution audio playback up native DSD512 and 32bit/384 kHz.
Crossfeed reduces listening fatigue by creating a more natural sound akin to listening to speakers.
Boasts Astell&Kern’s patented TERATON ALPHA Sound Solution technology.
A 4.1-inch, 720 x 1280px touchscreen tilts up to 60 degrees for easy control.
Support for Bluetooth® 5.0 provides greater range and a more stable wireless connection.
Support for 24-bit aptX™ HD and LDAC codecs, offers the best possible wireless sound quality.
Built-in battery provides up to 10.5 hours playback.

Headphone amp

To realise any hidden potential and run the most sophisticated and power-hungry headphones a dedicated amplifier is essential. The ACROCA1000 supports a four-step Gain Level setting that can run high-impedance headphones with a 15Vrms (Condition No Load) output level – without deterioration of sound quality.

Equipped with balanced 2.5mm and 4.4mm and unbalanced 3.5mm and 6.35mm outputs, the ACRO CA1000 can accommodate a wide variety of headphones. Using ultra-small relay parts, circuits for each output are physically separated from each other to minimise any internal noise interference that can adversely affect the quality of the signal and sound.

DAC magic

A digital-to analogue converter (DAC) contributes majorly to how close to the original recording the listener will experience. With a pedigree of designing and engineering award-winning premium DAPs Astell&Kern knowledge of DAC technology is unprecedented. The ACRO CA1000 arrives with a high-quality, high-performance Quad ES9068AS DAC that delivers a clear, detailed and balanced sound without distortion. The Quad-DAC also supports high-resolution audio playback up native DSD512 and 32bit/384 kHz, enabling the music fan to get even closer to the original studio sound, while revealing musical details never heard before.

First introduced in the A&futura SE180 DAP, the ACRO CA1000 features Astell&Kern’s patented TERATON ALPHA technology. The result of extensive research and development, this sound solution is designed to deliver audio playback close to the original sound through the audio output interface by use of effective power noise removal, efficient power management and amplification with minimal distortion.

The speaker effect with headphones

In a headphone environment where the left and right channels are clearly separated, ear fatigue can increase when listening over long periods. Activate the Crossfeed function and a more comfortable listening experience is revealed. This mode has the effect of blending the left and right channels, relieving ear fatigue by creating a more natural sound akin to listening to speakers. In this setting Shelf Cutoff, Shelf Gain, and Mixer Levels are adjustable according to listening tastes.

DAP credentials

More than just a powerful headphone amp, the ACRO CA1000 also features DAP capabilities, transforming it into the go-to-system for head-fi aficionados. A titling 4.1-inch touchscreen (up to 60-degrees) enables easy control of the player and amp settings with an intuitive Android OS and feature set taken from its award-winning portable DAPs.

Although not entirely mobile as an Astell&Kern DAP, this amp player hybrid system is compact and portable. Equipped with an 8,400mAh large capacity battery, the ACRO CA1000 can provide up

to 10.5 hours playback without a separate power supply. This headphone amp also supports USB-PD 2.0 (9V/3A) fast charging, so anyone with a charger that supports USB Power Delivery (USB-PD) can experience improved charging times – a one hour charge provides 50% battery, while it takes 2.5 hours for a full charge. A green light on the CA1000 will indicate when USB-PD fast charging is active.

An array of inputs and outputs allows connection of digital and analogue sources to expand the systems capabilities. These include Optical, Coaxial, Type-C USB digital inputs/outputs and RCA analog input/output.

The ACRO CA1000 harbours 256GB on-board memory that can be expanded up to 1TB via a microSD card slot, meaning users can stockpile thousands of hi-res albums. Elsewhere, Replay Gain functionality automatically and uniformly adjusts volume playback from sound sources up to 24-bit/192 kHz so playlists can be enjoyed throughout without reaching for the volume.

Connectivity

A BT Sink function connects the ACRO CA1000 to an external device, such as a smartphone, via Bluetooth, enabling music to be played back in high-quality on the headphone amp.

Elsewhere the ACRO CA1000 boasts Bluetooth® 5.0, providing greater range and a more stable wireless connection to headphones and, along with support for 24-bit aptX™ HD and LDAC codecs, offers the best possible wireless sound quality.

Alongside dual-band Wi-Fi support, the ACRO CA1000 features AK File Drop for easier wireless file transfers. Users can wirelessly transfer files through a PC, smartphone, or FTP program located on the same network to make music management even more convenient.

Any ACRO CA1000 owner with a Roon subscription can wireless stream all their high-resolution music, whether from Tidal, Qobuz services or digital music files stored on a hard-drive, computer or NAS drive, from this immersive music platform to the amp.

Out of this world design

The ACRO CA1000’s beautifully engineered aluminum body shape and the prominent and tactile volume wheel design are inspired by rugged space-age exploration vehicles that power across planetary terrain. The system still retains Astell&Kern’s signature angular shadow and light motif to seamless fit into the company’s bold and aspirational design language.

The Astell&Kern ACRO CA1000 is priced £1,999 / $2,100 / €2,299 and is available from www.astellkern.co.uk and local independent dealers.

TECHNICAL SPECIFICATIONS

General specifications

Body Colour: Moon Silver

Body Material: Aluminium

Display: 4.1-inch, 720 x 1280px touch screen

Supported Audio Formats: WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF

Sample rate:

PCM: 8kHz ~ 384kHz (8/16/24/32bits per Sample)
DSD Native: DSD64(1bit 2.8MHz), Stereo / DSD128(1bit 5.6MHz), Stereo / DSD256(1bit 11.2MHz), DSD512(1bit, 22.4MHz) Stereo

Output Level:

Headphone Out

[Low] Unbalanced 2Vrms / Balanced 4Vrms (Condition No Load)
[Mid] Unbalanced 4Vrms / Balanced 8Vrms (Condition No Load)
[High] Unbalanced 6Vrms / Balanced 12Vrms (Condition No Load)
[Super] Unbalanced 8Vrms / Balanced 15Vrms (Condition No Load)

RCA Out

2Vrms (Condition No Load)

CPU: Quad-core

DAC: ESS ES9068AS x4 (Quad-DAC)

Decoding: Support up to 32bit / 384kHz Bit to Bit playback

Headphone Outputs: Unbalanced (3.5mm, 6.35mm) / Balanced (2.5mm, 4.4mm)

Analog Inputs: RCA (Stereo pair) x1

Analog Outputs: RCA (Stereo pair) x1

Digital Inputs: Coaxial x1, Optical x1, USB(Type-C) x1

Digital Outputs: Optical(3.5mm) x1, USB(Type-C) x1

Wi-Fi: 802.11 a/b/g/n/ac (2.4/5GHz)

Bluetooth: V5.0 (A2DP, AVRCP, Qualcomm® aptX™ HD, LDAC)

Dimensions: 4.12″(104.9mm)[W] x 1.77″(45mm)[H] x 5.85″(148.8mm)[D]

Weight: about 919g (32.41oz)

Feature Enhancements: Firmware upgrade supported (OTA)

Audio specifications*

Frequency Response:

±0.024dB (Condition : 20Hz~20kHz) Unbalanced / ±0.018dB (Condition : 20Hz~20kHz) Balanced / ±0.048dB (Condition : 20Hz~20kHz) RCA
±0.059dB (Condition : 20Hz~70kHz) Unbalanced / ±0.056dB (Condition : 20Hz~70kHz) Balanced / ±0.048dB (Condition : 20Hz~70kHz) RCA

S/N: 107dB @ 1kHz, Unbalanced / 115dB @ 1kHz, Balanced / 119dB @ 1kHz, RCA

Crosstalk: -105dB @ 1kHz, Unbalanced / -124dB @ 1kHz, Balanced / -121dB @ 1kHz, RCA

THD+N: 0.005% @ 1kHz, Unbalanced / 0.002% @ 1kHz, Balanced / 0.0004% @ 1kHz, RCA

IMD SMPTE: 0.0008% 800Hz 10kHz (4:1) Unbalanced / 0.0004% 800Hz 10kHz (4:1) Balanced /0.0003% 800Hz 10kHz (4:1) RCA

Output Impedance: 3.5mm, 6.35mm (1ohm), 2.5mm, 4.4mm (2ohm), RCA (2ohm)

Clock Jitter: 25ps (Typ)

Reference Clock Jitter: 70ps

* Audio specifications will be based on Low Gain setting.

Built-in Memory: 256GB [NAND]

External Memory: microSD x1 (Max. 1TB)

Battery Capacity: 8,400mAh 3.8V Li-Polymer

Charge Time: about 2.5hours (9V / 3A PD2.0 Fast Charging) | 7hours (5V 2A General Charging)