iFi Audio Zen DAC Signature DAC
Since launching in the autumn of 2019, iFi’s best-selling ZEN DAC has proved a roaring success – no other DAC/headphone amp can touch it at the price, as a plethora of major awards attest. The new Signature edition takes this excellent platform, removes the headphone amp stage and upgrades the fully balanced circuitry to create a DAC for those who wish to maximise pure sonic performance.
In comparison to the ‘regular’ ZEN DAC, the Signature edition is a specialised, purist design. Without the builtin headphone amp, its sole purpose is to feed an external amp, whether this be a headphone amp or an amp and speakers. This simplification of its circuitry provides the opportunity to upgrade the signal path and critical components within it; while the existing ZEN DAC introduced the benefits of fully balanced circuit design at an extraordinarily low price point, the Signature edition further ups the ante with its enhanced true-differential balanced topology.
Various key surface-mounted circuit components have been upgraded to high-end devices, including Panasonic OS-CON and Elna Silmic II capacitors, while the circuit has been refined to ensure short, direct signal paths for optimal signal purity. This results in even greater sonic detail and expression.
The ZEN DAC Signature’s digital stage retains the True Native DAC architecture of its award-winning sibling, delivering bit-perfect PCM (up to 32-bit/384kHz), native DSD (up to DSD256) and DXD, plus MQA – the hi-res streaming technology, as used by Tidal’s ‘HiFi’ tier. The sample rate of incoming audio data is indicated by an multicoloured LED residing behind the aluminium volume control.
The iFi-programmed XMOS chip, which processes data received at the USB input, and jitter-eradicating, audiophile-grade oscillators, contribute to exemplary handling of digital audio signals as they are received, processed and converted to analogue form.
Aside from the removal of the integrated headphone amp and associated front-mounted outputs, the Signature edition’s connectivity is the same as the regular ZEN DAC. The USB Type B input supports the ‘SuperSpeed’ USB 3.0 standard, as well as USB 2.0 for backwards compatibility. It is asynchronous, meaning that the data rate is regulated solely by the ZEN DAC Signature’s specialised audio clock circuitry for accurate, jitter-free data transfer from the source device.
3 Alongside the USB input is a stereo pair of RCA sockets for single-ended connection to an amp, plus a Pentaconn 4.4mm output – this relatively new interface type enables balanced signal transfer between compact products that cannot accommodate traditional, bulky XLR connections. When connected to an amp or active speakers equipped with a balanced input – either a 4.4mm Pentaconn input, or stereo XLR inputs via a 4.4mmto-XLR cable – the full benefit of the ZEN DAC Signature’s balanced circuit design can be heard. iFi makes its own balanced cables to enable this connectivity; cables from other makers are also available.
As with the regular ZEN DAC, the Signature edition’s outputs can be switched between ‘variable’ and ‘fixed’. The variable setting applies volume control to the audio signal, enabling the ZEN DAC Signature to act as a preamp to connect directly to a power amp. The fixed option bypasses the volume control, fixing the output at 4.2V (balanced) or 2.1V (single-ended) for connection to an external preamp, integrated amp or active speakers with their own volume control.
ActivEQ – made-to-measure equalisation
The new Signature edition further improves sound quality with enhanced circuit design, while maintaining the versatile features of the ‘regular’ version and adding something special – a custom EQ setting precisely tailored across the entire frequency response curve to make the most of a popular headphone model.
This new feature, called ActivEQ, combines active and passive components to create a specific EQ curve to suit a particular pair of headphones, performed in the analogue domain without a hint of added noise or distortion. The first Signature model, the ZEN CAN Signature 6XX, features ActivEQ for the ‘Massdrop x Sennheiser HD 4 6XX’ – a popular pair of high-quality headphones (more than 120,000 sold to date) based on the Sennheiser HD 650 and created exclusively for Drop.com. These headphones are renowned for the quality of their midrange performance but exhibit some quirks in the bass and treble regions, which can be seen in frequency response measurements.
When the ‘HD 6XX’ button is pressed, the ZEN CAN Signature 6XX calibrates its signal to complement the headphone’s response characteristics right across the frequency range, thus tailoring its performance to precisely fit the HD 6XX like a made-to-measure suit. The benefits of this ActivEQ curve are equally applicable to Sennheiser’s HD 650 headphones, which share the same sonic characteristics. This feature can be switched on or off; without ActivEQ engaged, the ZEN CAN Signature 6XX’s performance is adroitly balanced to make the most of all manner of headphones and in-ear monitors.
ActivEQ aside, the Signature edition sports the same impressive facilities as the regular ZEN CAN. In the centre of the front panel is a smooth-acting volume control, flanked by several sockets and buttons. On the left, beside the power button and input switch, resides a control for selecting gain. Four settings in six dB steps – 0dB, 6dB, 12dB and 18db – enable the amp to precisely suit the connected headphones; unity gain (0dB) is useful to ensure low noise with sensitive in-ear monitors, while the higher gain settings make the most of tougher headphone loads, delivering excellent dynamic headroom.
To the right are a pair of headphone outputs – a 6.3mm output for headphones that have a standard singleended connector (compatible with all headphones) and a 4.4mm Pentaconn balanced output for headphones offering balanced connection. An increasing number of high-quality headphones and in-ear monitors either come so equipped or give the option of detaching the cable and upgrading to a 4.4mm Pentaconn connector, and this output makes the most of them (it is particularly recommended for high-impedance headphones).
Next to the headphone sockets is a button to engage the ActivEQ mode, plus a further sonic tailoring option – XSpace. This analogue processing modes compensates for the ‘in-head localisation’ effect that can occur when using headphones to listen to music that was mixed using a pair of speakers, effectively widening the headphone soundstage to deliver a more spacious and speaker-like experience. 5 Around the back, the ZEN CAN Signature 6XX offers stereo RCA and 3.5mm single-ended inputs, plus a balanced 4.4mm Pentaconn input. A 4.4mm balanced output is also provided, to connect to power amps equipped with a balanced input.
Balance of power
Like the regular ZEN CAN, the Signature edition features dual-mono, true-differential balanced circuitry – a topology usually reserved for high-end headphone amps – with a number of elements trickled down from the discrete Class A circuitry developed for iFi’s flagship headphone amplifier, the Pro iCAN. Key components have been upgraded to enhance performance in line with the improvements made to the ZEN DAC Signature, including the use of Panasonic OS-CON and Elna Silmic II capacitors.
The amp offers prodigious drive capability, delivering 1600mW (7.2V) into 32 ohms from the single-ended output, with 15V+ available to loads of 300 ohms or more through the balanced output, ensuring it takes even current-hungry planar headphones in its stride. Delivering ultra-low distortion, rich sonic detail, engaging dynamics and the ability to drive all manner of headphones with ease, the ZEN CAN Signature 6XX is a truly transcendent headphone amp at a down-to-earth price.
ActivEQ – crowd design initiative
The Signature 6XX isn’t the only ZEN CAN Signature edition that iFi is planning to make. A second version is on the cards, with ActivEQ tailored to another popular headphone model – and iFi wants headphone afficionados to vote for which model they want it to be.