iFi Debuts iPhono Black Label Phono Stage

WiFi HiFi

iFi Audio has revealed its new iPhono Black Label phono stage, designed for serious turntable users who want a separate phono stage.

Incorporating technology derived from the PH-77 phono preamplifier from sister-company AMR, iFi’s new flagship phono stage is user-configurable to match any MC/MM cartridge and suit every record. 

Driven by iFi’s Class A TubeState engine and Direct Drive Servoless design, it has a wide range of settings, including gain, load and EQ curves, to precisely suit the connected phono cartridge and the record being played, says iFi. It offers ultra-low distortion and class-leading dynamic range, super-low noise floor, marking one of the ‘quietest’ phono stages at any price, and high gain of 72dB, which iFi notes is on par with high-end phono stages that are twice the price.

Unlike a typical phono stage, the iPhono3 Black Label’s circuit is direct-coupled – that is to say, there is no coupling capacitor from cartridge to output. This is achieved without a conventional DC servo; iFi calls this design Direct Drive Servoless, incorporating a proprietary DC Infinity circuit to boosts DC gain to a level approaching infinity.

Once the feedback loop is closed, the DC gain cancels all offset voltages to deliver a direct-coupled output with 0V DC offset. The key to the DC Infinity circuit is that it only changes the gain below approximately 0.01Hz, while leaving the AC behaviour of the circuit at higher frequencies unchanged, injecting neither noise nor distortion into the audio signal. 

At the iPhono3 Black Label’s heart lies iFi’s third generation TubeState engine, the result of four decades of research into valve and transistor technology by the company’s Technical Director, Thorsten Loesch. TubeState is solid-state circuitry designed to capture the key attributes that make valve circuits so sonically appealing whilst maintaining ultra-low distortion.

Specialised JFET op-amps combine with a Class A buffer circuit featuring hand-matched PNP bibolar transistors; the buffer circuit minimizes the loading of the amplifier circuit and biases the output stage into single-ended Class A. High input impedance approaches the ‘zero loading’ a valve grid provides, with excellent drive ability and vanishingly low THD (Total Harmonic Distortion).

A series of DIP switches on the underside of the unit enable gain and load to be set – essential to wring the very best performance from a high-performance cartridge. Gain can be adjusted between 36dB and 72dB, alongside a wide variety of load values – eight for MC cartridges and a further five for MM cartridges. Spending a little time to set up the ideal combination to match the cartridge on your turntable delivers great sonic reward – iFi has created an online ‘cartridge calculator’ to assist with this.

A toggle switch at one end of the iPhono3 Black Label allows the user to select between three EQ curves: RIAA, Columbia and Decca. It can generally be assumed that LPs produced from 1980 onwards were made using RIAA equalization, which means they should sound best with the RIAA setting engaged. But records released before1980 may have been made using different equalization and may sound better with the Columbia or Decca EQ curve engaged.

This applies not only to records released by those specific labels. For example, many of Deutsche Grammophon’s classical records released before 1980 can sound dry and flat – this is because they were produced using the Decca EQ curve and very few phono stages provide this option, but with the correct EQ applied they sound superb. As a general rule, if an LP sounds thin and edgy with the RIAA EQ, try the Decca EQ curve; if it sounds overly bright with overblown bass, try the Columbia setting.

Further DIP switches on the underside allow the RIAA EQ setting to be further tuned to taste. Users can choose the standard RIAA curve – applied with +/- 0.2dB accuracy – or an enhanced version called ‘eRIAA’ offering extended high-frequency response. Alternatively, if the user has problems with warped records, which can cause a large signal output in the subsonic region, the IEC setting takes the standard RIAA curve and applies a subsonic filter to tackle the issue. Finally, the eRIAA+IEC setting applies the subsonic filter to the enhanced RIAA curve.

Components used in the circuit design include a Burr-Brown SoundPlus op-amp, complemented by Panasonic ECPU film capacitors; computer-matched pair of planar high-gain bipolar input transistors lowers output noise; four Nichicon 470uF/6.3V capacitors deliver lower ESR (Equivalent Series Resistance) and improve speed and bass performance; eight Panasonic OS-CON capacitors totalling 14,800uF deliver low ESR, excellent noise reduction and exemplary frequency characteristics; numerous TDK C0G type capacitors, which have lower thermal drift and distortion than Polystyrene capacitors; two Elna Silmic II capacitors for the power supply; and numerous Vishay MELF thin film resistors.

The iFi iPhono Black Label comes with the 15V version of iFi’s new iPower X ultra-low-noise AC/DC power supply and sells in Canada through iFi’s Canadian distributor Motet Distribution for MSRP $1,499.