iFi AUDIO Pro iCAN Headphone Amplifier

iFi is proud to present its flagship Professional 'Pro' series. The first product in the range is the Pro iCAN - a studio-grade headphone amplifier AND audiophile line-stage. Inside beats 'two hearts' as there is are two individual Solid-State and Tube amplification sections - selectable on the go. There is nothing quite like the Pro iCAN; literally.

Flagship, studio-grade headphone amplifier
The Pro iCAN will for many, be used as a top-of-the-line, headphone amplifier that drives anything and everything - from CIEMs through to the most difficult to drive headphone ever made, the AKG K-1000. Further, Gain is adjustable from 0dB/9dB/18dB. The Pro iCAN can output >10V in Single-Ended mode and 20V in Balanced-mode. The 20V mode is equivalent 100W into a 4Ohms speaker. So the Pro iCAN can drive almost any headphone into very hard-clipping (protection circuitry typically kicks in under such circumstances).

And audiophile line-stage
The Pro iCAN has at the core, a Japan Alps motorized rotary volume potentiometer. This is the '6-Track' version with 4 tracks used for a true balanced volume control. This is the litmus test for any amplifier to see if it is truly balanced or operates internally in single-ended mode. Those using '2-Track' volume controls may offer balanced in and out, but are not true balanced designs. The Pro iCAN however is fully-balanced from beginning to end.

True Differential Balanced
At the upper end of the headphone amplifier market, despite the best protestations of 'balanced' things are not always what they seem. This is a curious case of 'Is balance balanced?'. For headphones, it does make good design sense to implement a balanced topology (the possibility of higher power, increase dynamic range and lower noise etc.) It goes without saying that the balanced design should be balanced all the way through, 'end-to-end'.

The typical so-called 'Balanced' headphone amplifier
• Input/Output: Balanced
• Internal Circuitry: Single-Ended

The majority of 'balanced' high-ended headphone amplifiers are actually single-ended amplifiers with balanced inputs and outputs. The balanced input will be converted into single-ended operation inside the amplifier, then converted back to balanced just before the output: The following block diagram depicts the balanced input through to the amplifier (orange) which afterwards, reverts to single-ended and runs through many single-ended stages before then going to the balanced outputs.

The balanced input signal will first be converted into single-ended operation by extra circuitry added to the single-ended signal path. The volume control and actual headphone amplifier are formed by a pure, single-ended circuit. To provide balanced drive to the headphone, the signal is inverted using more circuitry added to the single-ended audio path. A sure fire giveaway of such circuitry is the use of a 2-Deck volume control (c.f. 4-Deck for true balanced circuitry), as well as having more than four gain/current buffer blocks among two channels. At the input, the additional balanced to single-ended conversion circuit generates extra noise on top of the volume control pot.

True Differential Balanced - Pro iCAN
• Input/Output: Balanced
• Internal Circuitry: Balanced

The Pro iCAN however, is true balanced end-to-end, from the input all the way through to the outputs. It operates with full-differential internal signaling, meaning the signal is always remains two separate signals of equal level but opposite polarity. This is what iFi call True Differential Balanced.

The Pro iCAN circuit is fully-balanced with completely equal circuit sections for Positive (Hot) and Negative (Cold) signal phase of each channel. The Volume control has 6-Decks, two decks each control the volume of one channel and the other two decks are used for monitoring the volume control operation. This exceptional volume control potentiometer is custom made for iFi by ALPS Japan and has no parallel from other makers.

Note

In professional audio, 'Balanced Amplifier' only means the Input/Output connections are balanced, the internal circuits are actually single-ended (if the internal circuit is also balanced, it will be called differential). But in the Hi Fi world, most people view a 'Balanced Amplifier' as balanced all the way, from end-to-end and incorrectly assume even the internal circuits are balanced.

Tube/ Solid-State Real-time Switching
Compared to high-end headphone amplifiers, the tube stage of the Pro iCAN is different in two-ways. First, iFi don't use good-quality 6922s or similar. Instead iFi use the very best; General Electric 5670 which is the premium variant with a different pinout. Second and just as important is the circuit design. Unlike other headphone amplifiers that have the same circuit and just switch in/out the tube section, the Pro iCAN is the very first of its kind that has two individual input circuits - one tube and one Solid-State. This results in the best sonics of both worlds because the signal path is the shortest and there is no compromise to 'shoe horn' the tubes into an already existing solid-state circuit.

For the first time, one can enjoy both the sound of Solid-State and Tubes in a single package (rather than as an 'Effect Type' add-on within an otherwise conventional solid-state design) and be able to switch in real-time. For some recordings and headphones/loudspeakers, Solid-State may sound 'more lively'. For others, Tube and Tube+ (especially Tube+) will sound more 'luxurious'. Select the one that sounds best for that particular moment, be it the recording, the mood or even the weather. After all, enjoying music is an experience to be savored and not a scientific research exercise.

Class A Solid-State, J-FETs and Fully-Discrete
The Solid-State amplification section of the Pro iCAN is just as seriously executed as the Tube amplification section. The amplifier audio circuit is a development of iFi's revolutionary 'TubeState' design. It is fully discrete, fully-balanced with either tube or J-FET input switchable, bipolar second stage and MOSFET-buffered bipolar class A Power stage (with Class AB for low impedance headphones at very high levels). The resulting circuit may be best described as 'tri-brid' where each device is used to greatest sonic advantage while minimizing any drawbacks. Furthermore, the circuit is pure DC coupled to avoid using any sonically-degrading coupling capacitors.

3D Holographic not one but two circuits
There are two 3D Holographic SoundSystems:

For Headphones: (Headphone Outputs)
The 3D Holographic for Headphones is not based on a standard cross-feed system, as found in some High-End headphone amplifiers. Many so called '3D systems' are usually DSP based that artificially effect the sound and add unwanted reverb in order to simulate a 'spacious' type of sound. It's true that traditional cross-feed tends to produce an 'out of head' sound, but with much diminished spatial components and a narrower soundstage, sometimes almost approaching mono. Most DSP based 3D designs produce an unnatural, echo-like sound, which may initially be impressive, but soon becomes tiring.

By contrast, 3D Holographic for Headphones, provides not only 'out of head' placement of the sound sources, but renders the whole sound field in a manner that strongly parallels listening to loudspeakers in a normal room, all achieved without the added reverb. This is the first system in commercial production to achieve this.

For Loudspeakers: (Line Outputs)
The 3D Holographic for loudspeakers is an analogue matrix circuit that has two distinct functions:

• Corrects the fundamental spatial distortion in stereo recordings
• Increase the width of the apparent soundstage beyond the width dictated by the loudspeaker placement

3D Holographic Sound for Loudspeakers
The 3D Holographic circuit for loudspeakers corrects a distortion of the sound field caused by recording via microphones and playback via loudspeakers. This sound field distortion was first described by Alan Dower Blumlein (the Inventor of Stereophonic sound) and corrected by EMI in early 'Stereosonic' recordings. However, the original Stereosonic circuit tended to result in a narrower soundstage than if recorded straight and often overcompensated distortion of the soundstage perspective. iFi's 3D Holographic systems avoid this and instead, allow an expansion of the width of the sound stage. These modes can also be used to enhance the imaging of recordings that offer poor spatiality.

XBass Correction System
Different recordings and different headphones exhibit different frequency responses. XBass is an analogue signal processing (ASP) circuitry and it is sonically superior to Digital Signal Processing (DSP) systems. XBass is tailored to correct the bass deficiency in the headphone/loudspeaker and achieve the desired level. It is NOT a traditional tone or loudness control and provides a minimum of 12dB boost at 10/20/40Hz.

Reference class parts quality
The Pro iCAN employed TDK Japan-made C0G type capacitors and Vishay MELF type thin film resistors. These are complimented by Panasonic Japan-made ECPU Film Capacitors explicitly designed for audio use with extremely low distortion (<0.00001% at 1V/10kHz). iFi employed ELNA Japan-made Silmic II capacitors for the power supplies. These use special silk fiber paper for the isolating barrier resulting in decreased odd-order distortion and reduced microphonics/mechanical resonances.