ZEN Air CAN - Let's take another look! At just £99/€99/$99, the ZEN Air CAN offers astonishing value for money – its circuitry and facilities have been simplified form the original ZEN CAN but the quality of what has been retained is remarkable. Like the ZEN CAN, it has no digital input of any kind; it connects to any audio source with an analogue output, such as the headphone output from a DAP (Digital Audio Player), a laptop, a tablet or a smartphone, or the RCA outputs from, say, a CD player, or a phono stage like the ZEN Air Phono. It could also be paired with the ZEN Air Blue to add Bluetooth reception, or perhaps combined with the ZEN Air DAC to upgrade the DAC’s headphone amp stage. Tech highlights Whilst the fully balanced circuit topology of the ZEN CAN has been simplified to make its Air equivalent, it retains the use of discrete, high-grade components and a separate, symmetrical layout between channels – an exceptional level of design at such an eminently affordable price point. Though not quite boasting the output level of the mainline ZEN CAN, there’s still ample power on tap to drive all manner of headphones with ease – 1200mW into a 32-ohm load – coupled with ultra-low distortion to deliver impressive musical texture and detail. iFi’s quad-amp circuitry features custom OVA-series FET op-amps using a ‘folded cascode’ design, with specialised feedback circuitry to optimise performance. The input stage features automatic gain matching between inputs and feeds a TOCOS precision potentiometer, while the discrete, complementary bipolar output stage utilises the same Class A buffer found in more expensive iFi headphone amps. The power supply circuitry includes ‘stealth mode’ voltage conversion, with linear regulation, noise filtering, physical isolation from sensitive audio circuits and more than 4,000uF capacitance to keep ample power in reserve to respond to musical transients. Alloy shielding within the thermoplastic polymer outer case protects sensitive signal paths from interference. Even the way the ZEN Air CAN switches between settings has been engineered to ensure sonic transparency – FET-based switching is handled by a microcontroller, which only ‘wakes up’ when the user changes a setting, thus eradicating any sonically deleterious interference. All this painstaking attention to detail would be impressive in a high-end headphone amp; that fact that iFi has succeeded in implementing such high-quality circuitry in one retailing at just £99/€99/$99 is nothing short of remarkable. Features and connectivity Just as remarkable is the retention of so much of the ZEN CAN’s highly impressive feature set. XBass+, iFi’s sophisticated bass enhancer, and XSpace, which widens the soundstage to compensate for ‘in-head localisation’ effects, are both present. Gain adjustment to precisely suit the connected headphones is also provided, with three steps – 0dB, 9dB and 18dB – in place of the ZEN CAN’s four steps. The ZEN CAN’s dual headphone outputs – 6.3mm and 4.4mm – are also repeated here, although the 4.4mm output is not fully balanced as it is on the ZEN CAN. Instead, it benefits from iFi’s S-Balanced circuit design, which cuts noise and crosstalk by 50 per cent with single-ended headphone connections. Similarly, the ZEN Air CAN sports three analogue inputs, the same number as the mainline ZEN CAN – but here, the 4.4mm balanced input is swapped for an extra pair of single-ended RCA sockets, providing two stereo RCA inputs and one 3.5mm S-Balanced socket in total. ZEN Air Phono - Let's recap! The ZEN Air Phono offers excellent performance with both MM and MC cartridges and it also delivers an ultra-low noise performance that’s measurably and audibly the cleanest and clearest at its price point – just like its big brother, the award-winning ZEN Phono. This ensures that the listener hears every drop of detail against a super-quiet background. Tech highlights Like other ZEN Air devices, the ZEN Air Phono simplifies the fully balanced circuit design of its mainline ZEN equivalent but still retains a symmetrical channel layout with high-quality surface-mounted components offering low ESL (Equivalent Series Resistance), high stability and low distortion. This pays dividends in terms of sound quality and the accuracy of RIAA equalisation. In common with many iFi devices, a custom OV Series op-amp is used – in this case, the OVA2637A – further contributing to the price-busting sonic performance thanks to its ultra-low distortion characteristics (THD <0.0001%). The finest high-end phono stages have their own high-quality power supplies, effectively ‘regenerating’ electricity drawn from the mains to amplify the delicate audio signal from the cartridge without adding noise. Like the ZEN Phono, the ZEN Air Phono achieves this aim but not in a conventional way; its power supply has an oscillation frequency of 1.2MHz, at least 20,000 times that of mains electricity. In this circuit, a filtering capacitor with a 10uF rating is equivalent to 200,000uF at lower, audible frequencies, delivering superb filtering power. The power supply circuitry is located on its own ‘island’ on the circuit board to ensure there is no contamination of the audio signal – just super-clean +/-15V DC. Features and connectivity Another rarity at this price level is a subsonic filter, engaged via a front-panel button to tackle the large subsonic signal output caused by warped records. A feature of all iFi phono stages, this proprietary circuit ‘intelligently’ filters out the unwanted subsonic output without affecting any deep bass on the recording – an undesirable side effect of some warp filters. Connectivity is kept simple: gold-plated stereo RCA sockets in and out, without the 4.4mm balanced output option of the mainline ZEN Phono. A grounding terminal is also provided; attach a turntable’s grounding wire to this to eliminate audible hum. The ZEN Phono’s four gain settings to suit different cartridge types are replaced by a simple MM/MC switch (40dB/64dB gain). The ZEN Air Phono’s high-gain MC circuit still delivers a remarkable signal-to-noise-ratio of -82dB – no other phono stage at the price comes close.