ZEN Phono is the latest addition to iFi’s ZEN range and is an entry-level phono stage.

iFi continues to expand its ZEN Series of affordable, desktop-sized audio devices with the ZEN Phono, a phono stage (or phono preamplifier, if you prefer) at £149. The ZEN Phono is the first sub-£200 phono stage iFi has made to match all manner of phono cartridges, whether moving magnet or moving coil.

The new iFi ZEN Phono is just £149

Phono Stage

Every turntable needs a phono stage to amplify the low-level output from a phono cartridge to ‘line level’ and apply RIAA equalisation. Some integrated amps and preamps have phono stages built in, but these vary in quality and are rarely as good as a well-designed offboard phono stage placed in the signal chain between the turntable and a line-level input on the amp.

iFi ZEN Phono, compact and budget friendly

The ZEN Phono has been designed to push the boundaries of what can be achieved in an entry-level phono stage. The ZEN Phono’s circuitry is of balanced, symmetrical dual-mono design – a topology usually reserved for high-end audio products owing to complexity and cost. Balanced circuit design has the ability the reduce noise and crosstalk and has long been championed by high-end audio electronics engineer John Curl  now a technical consultant for iFi .Curl has worked with iFi’s in-house technical team, headed by Thorsten Loesch, to produce the circuit design phono stage.

Balanced Circuitry

The ZEN Phono’s balanced circuitry contains surface-mounted components, for example, the capacitors used include TDK C0G and Murata multilayer ceramic types, as well as Panasonic ECPU polyphenylene sulphide film devices – none of these are cheap, but their class-leading ESL (Equivalent Series Resistance) and individual qualities such as high stability and low distortion pay great dividends in terms of sound quality and the accuracy of RIAA equalisation.

In common with many iFi audio products, the ZEN Phono incorporates a custom OV Series op-amp,  in this case, the OVA2637.

The iFi ZEN Phono features balanced circuitry

Power Supply

The best phono stages on the market create their own power supply off the mains, similar to a mains regenerator, in or er to amplify the audio signal from the cartridge without adding noise. The ZEN Phono achieves this aim, but not in a conventional way; it creates a power supply with an oscillation frequency of 1.2MHz, which is 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.

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 clean +/-12V DC.

MM And MC Cartridges

Phono cartridges vary greatly in their technical characteristics, but few sub-£200 phono stages handle moving coil (MC) cartridges in addition to moving magnet (MM) types.

The ZEN Phono is an exception, delivering a range of gain settings from 36dB to 72dB. . There are four gain settings in total: 36dB (MM), 48dB (high output MC), 60dB (low-output MC) and 72dB (very-low-output MC). This enables the ZEN Phono to take even the more exotic MC cartridge types in its stride.

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.

The iFi ZEN Phono for MM and MC cartridges

This is how it works: vinyl cutting lathes incorporate a so-called ‘elliptical filter’, which means that low-level bass on an LP is invariably mono and creates only horizontal movement of the stylus. Therefore, any low-frequency vertical movement of the stylus as it tracks the LP can only be the result of record warp. iFi’s subsonic filter removes the effect of record warp from the vertical plane, doing its job efficiently without the common drawbacks of attenuating any low bass or adding group delay.

Connections

As well as the usual stereo RCA inputs and outputs, gold-plated for optimal signal integrity, the ZEN Phono’s rear sports a 4.4mm Pentaconn balanced output. This can be used to connect to an amp or active speakers equipped with a balanced input,  either a Pentaconn 4.4mm input, such as the one found on the ZEN CAN analogue headphone amp, or XLR inputs via an adapter. This enables a fully balanced connection that makes the most of the ZEN Phono’s balanced circuitry.

A grounding terminal is also provided; attach a turntable’s grounding wire to this to avoid ground loop issues that can cause an audible hum. Even the way the ZEN Phono switches between settings has been engineered to ensure sonic transparency, handled by a microcontroller that only ‘wakes up’ when a setting is changed to avoid any sonically deleterious electronic noise.

Price

The ZEN Phono is the fourth product to join iFi’s ZEN Series, available from selected retailers from September, priced at £149.

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