Do not be confused by the weight and dimensions of the IFi Audio Zen – in fact, this is a completely grown-up preamplifier with wide capabilities and impressive technical parameters.
It’s all about the mentality and experience of the developers: some are following the beaten path, improving only the element base and adding new options, while others are looking for new, more effective approaches to solve the same problem. And British iFi Audio is one of those innovators.
The company positions the Zen Phono as an “ultra-affordable component,” so I was a bit lukewarm at first. But I looked into the specifications and was thoroughly intrigued: the signal-to-noise ratio at the MM input is -94 dBA, four gain values, and three of them are for MC heads with different recoil. Plus the presence of a clever subsonic filter and balanced output … How did you manage to implement this with the dimensions of the case 158 x 117 x 35 mm? To figure it out, unscrew the four screws and remove the printed circuit board.
The first step is to consider the power supply circuits. A 5 V DC voltage from the wall adapter is supplied to the converter, which generates a bipolar supply of +/- 12 volts. According to the manufacturer, the circuit operates at a frequency of 1.2 MHz, so it does not induce interference in the audio range. The current consumed from the adapter is quite large, 0.5 amperes.
Its main feature is the use of unique Texas Instruments OVA2637 operational amplifiers in the sound path.
The Zen Phono circuit was designed by a team of engineers led by Thorsten Loesch, with contributions from cult audio specialist John Curl. Its main feature is the use of unique Texas Instruments OVA2637 operational amplifiers in the sound path, about which I could not find any information on the Web. It is possible that this is some kind of custom development, since there is only a short description for it posted on the iFi Audio website.
It mentions extremely low noise density, distortion of the order of 0.0001%, high speed and 100dB CMR. Each channel has only one dual op-amp, i.e. the signal path is extremely short here, and with power-up transistor buffers at the output. Despite the laconicism of the scheme, here you can set four gain factors for heads with different recoil – MM, MC High, MC Low and MC Very Low. In decibels, the values will be 36, 48, 60 and 72, respectively, i.e. in the latter case, the input signal is amplified by 3980 times, and the signal-to-noise ratio does not exceed -79 dBA. This is a truly unique indicator, especially when you consider the price of the corrector.
The signal level at the RCA outputs with distortions less than 1% can reach 20 volts, i.e. the overload capacity of the circuit is much higher than the recommended 20 dB. This means that Zen Phono is able to reproduce sharp signal peaks at HF without wheezing, and the clicks of the records will not be accompanied by noise plumes. and the signal-to-noise ratio does not exceed -79 dBA.
This is a truly unique indicator, especially when you consider the price of the corrector. The signal level at the RCA outputs with distortions less than 1% can reach 20 volts, i.e. the overload capacity of the circuit is much higher than the recommended 20 dB.
This means that Zen Phono is able to reproduce sharp signal peaks at HF without wheezing, and the clicks of the plates will not be accompanied by noise trains. and the signal-to-noise ratio does not exceed -79 dBA. This is a truly unique indicator, especially when you consider the price of the corrector.
The signal level at the RCA outputs with distortions less than 1% can reach 20 volts, i.e. the overload capacity of the circuit is much higher than the recommended 20 dB. This means that Zen Phono is able to reproduce sharp signal peaks at HF without wheezing, and the clicks of the plates will not be accompanied by noise trains.
In the correction circuits, multilayer capacitors TDK C0G are involved, which, as stated in the description, are not inferior in their parameters to Teflon ones. The power supply is decoupled by Panasonic SMD electrolytes. Internal switching is carried out by the HCT4053 microcircuit, and when switching the head type “on the fly” there are no claps in the columns, the set parameters change smoothly. Deviations from the RIAA standard curve do not exceed 0.15 dB.
The infra-low-frequency filter is activated by a button on the front panel. Its circuit is the same as in the more expensive iPhono2 and iPhono2 models – it cuts off the mechanical rumble of the player without introducing phase distortions into the signal.
The balanced signal is picked up from the 4.4mm Pentaconn jack.
Despite the laconic nature of the circuit, it is possible to set four gain factors for heads with different recoil – MM, MC High, MC Low and MC Very Low.
To begin with, I decided to measure the real noise level of the Zen Phono using a special Keenwood VT-172 device. According to the DIN Noise standard (weighting filter A), with respect to the output level of 1 volt, the declared signal-to-noise ratios were confirmed with an accuracy of 1 – 2 dB.
For testing on music, I took turns installing two heads on the turntable – MC Denon DL103 with an output voltage of 0.3 mV and MM Goldring 2400 with an output of 6.5 mV. Accordingly, the gain of the corrector was set at 40 and 60 dB.
In both versions, the individual character of the Zen Phono’s sound could be easily traced. Immediately you notice a clean, literally washed out upper range. There are many overtones in the sound of the cymbals, you can feel a real blow to the metal, the vibrations seem quite natural. The middle is also good – it is informative and open, the timbres of instruments and singing voices are lively, with practically no simplifications. Here you can already appreciate the advantages of vinyl as a medium: a pleasant sound with a plastic and free flow of music.
There are many overtones in the sound of cymbals, you can feel a real blow to the metal, the vibrations seem to be quite natural.
Despite the simplicity of the scheme, its task, i.e. Formation of a standard RIAA characteristic, the corrector performs accurately. His tonal balance is even, the attack of sharp sounds is not prolonged. The only difference between Zen Phono and more expensive preamps is that it has a slightly less bodily low mids and less energetic bass. Nevertheless, he is able to show the emotional content of a piece of music, and through this, and influence the mood of the listener. It is also important that the corrector shows the characteristic differences between MM and MC heads, i.e. its sound resolution is quite high.
It is difficult to evaluate the work of the infra-low-frequency filter by ear, since it has a range that is not available for most acoustic systems. If you listen with good quality headphones, you will notice a lack of some tension in the lowest register. But the fact that the filter does not affect the construction of the soundstage is obvious.
In terms of channel separation, the transfer of spatial effects, you will never say that you are dealing with an entry-level corrector.
It is generally difficult to find fault with creating a stereo picture here. In terms of channel separation, the transfer of spatial effects, you will never say that you are dealing with an entry-level corrector. Of course, a lot here depends on the class of the head, the preamplifier itself is perceived to be quite transparent.
It is important that in terms of the nature of the sound, it is completely different from a typical budget model with a dull, inexpressive sound. There are no such numbers on the market now, but Zen Phono is able to show both liveliness and accuracy, and, where needed, festive brightness.
More info: ifi-audio.com
