iFi ZEN Phono Preamplifier/Phono Stage

Hissless whisper

Flagship phono amplifiers create their own power supply off the mains, like a mains regenerator. This is fundamental to a well-designed phono stage. Without this, it will struggle to amplify the signal without added noise. This is why phono stages ‘hiss’ so annoyingly.

Unusually, the ZEN Phono has its own high-tech clean power supply. It creates a 1.2MHz power supply (20,000x mains frequency of 60Hz). In this circuit, a 10uF filtering capacitor = 200,000uF at lower, audible frequencies. With serious levels of noise filtration, it performs at the level of classic LC filtering circuits as found in classic tube amplifiers. On its own ‘island’ PCB, it is isolated so there is no noise pollution of the analogue stage.

Just super clean +/- 12V DC.

Measured EIN (Equivalent Input Noise) is -151dBV. It is 20dBV quieter than some Stereophile Class A+ phonos which are -131dBV.

Mil-spec RIAA

The EQ circuit uses multiple TDK C0G capacitors in parallel. This is for best stability and the least distortion. They beat polystyrene capacitors and are close to Teflon. Read more here. 

Already using the lowest tolerance capacitors combined with multiples in parallel, tolerance is exponentially improved by the square root of the number of capacitors. This is quite a natty circuit design.

The RIAA EQ tolerance level (+/- 0.15dB) is impressive as it is en par with hand-selected capacitors!

With great circuit comes great components

The ZEN Phono has some seriously good audio components backing up the fab circuit design which has trickled-down from its ultra-fidelity AMR PH-77 and iFi iPhono siblings.

Scroll down for more on the most consequential circuit highlights/boutique components.

Super sub-sonic

The intelligent sub-sonic filter is from the iPhono range and is quite special.

Normal sub-sonic filters remove ‘rumble’ and bass and add phase issues.

Our unique AI phono sub-sonic filter removes ‘rumble’ only.

• ZEN Phono: – 151dBV 
• Stereophile Class A+ rated Phono: – 131dBV

 

With MM/MC, high/low and very low, the ZEN Phono is able to handle just about any cartridge. From 36dB all the way up to 72dB. So as your vinyl system grows over time, the ZEN Phono will always keep up.

Balanced circuit design. Just not seen at this price point it is a superior method to the traditional single-ended circuit approach. Balanced circuits reduce noise and crosstalk. Less Interference – clearer sound.

 

This OV series operational amplifier is another example of a top-notch component used to get extremely low noise, low distortion (0.0001%) and wide bandwidth.

Learn more here.

 

Panasonic ECPU capacitors. Each ECPU capacitor is constructed from some 3,500 layers of ultra-thin dielectrics less than 0.5μm thickness. It offers class-leading Equivalent Series Resistance (ESR), low impedance and frequency stability and vanishingly low distortion.

 

TI low-noise ICs offer great unity gain bandwidth, very low noise and distortion, high output drive capability, Common-mode and Power Supply Rejection Ratios of over 100 dB, wide maximum-output-swing bandwidths and high slew rates.

Learn more here.

 

TDK C0G (Class 1 ceramic) capacitors offer high stability and low losses for resonant circuit applications. They are pricey but are a perfect addition to our products.

 

muRata control-type, low-ESR high-Q multi-layer capacitors. The ‘ESR control’ aspect of the Murata is something special. Their noise suppression abilities are impressive.