AV Systems Guide
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Design and Features
Power-up and Amplify
In today’s world, miniaturization is the name of the game. Whatever the technology, you can safely assume that manufacturers are seeking new ways to make it more compact. Smartphones get sleeker, notebooks get lighter, cameras get smaller so on and so forth. It seems the end goal for everyone is to get every gadget to fit in your pocket. However one product category that has yet to get onboard this trend fully is high-end audio. Sure headphones have been made easier to carry on the move and there are a number of portable amplifiers and DACs. But on the whole, top of the line audio equipment seems to promote sedentary usage.
However, iFi Micro looks to change that opinion with a range of new compact products which include amplifiers, an outboard DAC and even a power supply. We had the good fortune of testing these devices in our labs and as per the title of the review, we're focusing this article on the iFiMicro iCan headphone amplifier.
Design and Circuitry
From first appearances, the iFi Micro iCan looks like a regular amplifier intended for use with desktops or notebooks. The device measures in at 28mm x 68mm x 158mm and weighs approximately 215 grams. Small, compact and light, the iCan will not take up a lot of space on your desk and can even be slid into a carrying bag to be used with a notebook or an Ultrabook when you set up a mobile workstation. While it might look portable, note that it needs to powered at all times and it's not meant for use on-the-go (we cover more about this aspect after the photo break).
With regards to aesthetics, the amplifier has a simple aluminum finish and a bit of chrome around the edges. But the innards of the amplifier have always been much more important than its looks. The iFi Micro iCan is a Class A TubeState amplifier which has been fitted with what iFi calls a "tri-brid" circuit due to the fact that it combines the best of bi-polar, JFET and "Advanced Discrete" devices.
Class A Amplification Basics
A Class A amplifier is defined as an amplifier where the 100 percent of the input signal is used (as opposed to the constant switching on/off of the output device for other classes of amplification that can't use the full input signal). As such, the active element inside the amplifier conducts electricity at all times. The advantages of Class A amplifiers include simpler design and construction for manufacturers as they can handle single devices single-ended (or also simply referred to devices with resistance). The amplifying device is also biased (always on with a constant flow of current), so the device is always conducting to some extent reducing "turn on" times drastically. Due to these characteristics, do note that many Class A amplifiers exhibit a certain degree of noise with headphones when no audio is playing. It also goes without saying that Class A amplifiers are also power inefficient which limits battery operation. This is also the reason why the iFi Micro iCan requires to be powered at all times and it isn't designed for on-the-go usage despite its small size.
All in all though, Class A amplifiers are considered to be among the highest quality of amplifiers available on the market and.are highly prized by audiophiles for their absence of crossover distortion as well as reduced odd-harmonic and high-order harmonic distortion. As can be expected, seeing that the iFi Micro iCan is a Class A amplifier, the device has an extremely low total harmonic distortion of less than 0.003 percent (400mV/150R).
Tri-Brid Circuit Design
Moving on, the tri-brid circuitry is quite interesting to delve into. Generally amplifiers are split into the categories of tube / valve and transistor amplifiers. Transistor amplifiers are further broken down into Bipolar Junction Transistors (BJT), Field Effect Transistors (FET) and Metal Oxide Semi-conductor Field Effect transistors (MOSFET). The basic aim of an amplifier is to increase the amplitude of the signal by adding gain. A tube amplifier accomplishes this with the help of vacuum tubes (hence the name) and are well known for their warm sound. However it is important to note that the iFi Micro iCan is a Class A amplifier but not a tube amplifier. The term "TubeState", which can be quite misleading, is a marketing term used to denote the amplifier's "tube-ish" sound which we will be looking out for in our testing segment. No actual tubes are used in the amplifier. The iFi Micro iCan has tri-brid circuitry which is claimed to cherry pick the best features from BJT and JFET.
Breaking down the tech jargon, a bipolar junction transistor (BJT) is one that has the ability to emit more than one output signal. The output is dependent on the negative or positive polarity of the input signal. Not only is a bipolar amplifier able to handle multiple signals, but it can tack on additional gain as the signal is being passed through, resulting in lower levels of noise incurrence. JFET stands for junction gate field-effect transistor and you can picture this transistor as a garden hose for the flow of electric charge. You can control the cross section area of the JFET which also gives you control over the current that flows from the source. In general FET technology offers better thermal stability when compared to BJTs. Seeing that iFi Micro has stated all of these components are utilized in the iCan, we will be holding it up to an extremely high standard during our performance test section.
Before rounding up the design section, mention must be made of the unassuming wall wart type power supply of the amplifier. According to iFi Micro, the iCan’s adapter comes with Ultra Low Noise switched-mode power supply which has been purpose-built for audio applications. Supposedly, the power supply is quieter than other competitors on the market at present.
Features and Enhancements
The result of all this design and circuit trickery is that the iFi Micro iCan has a healthy and robust 400mW output at 32 Ohms as well as a wide frequency range of 0.5Hz to 500,000Hz. For an amplifier that is priced at just S$339, these are extremely solid and impressive figures.
With regards to ports, the iCan has a power socket and two stereo analog input ports on the rear panel. The front panel presents a volume knob, a ¼-inch headphone jack and two flick switches. The flick switches represent two special audio enhancement features for the iFi Micro iCan.
The first flick switch is called "XBass" and as the name suggests, it is a specific bass EQ system. The flick switch has three particular settings for XBass. These are "Direct" - which does not provide any bass boost, "Single Dot" - intended for headphones with average bass, and "Triple Dot" - which is meant to be used for bass shy headphones.
The "3D Holographic Sound" feature is meant to help improve and boost the soundstage of the headphones. There is a similar "Direct, Single Dot, Three Dot" setup for this feature as well. Direct does not engage the effects when listening, while "Single Dot" is intended for turning a good stereo soundstage into a 3D soundstage. The "Three Dot" setting is targeted for use with flat sounding headphones and recordings. Seeing that iFi Micro states that "3D Holographic Sound" can take the sound from "inside your head" to "inside your room", we will have to test the veracity of their claims in our performance section.
Although we cannot fault the decision to add presets to the amplifier and the flick switches are always a joy to use, the non-mirrored setup of the two switches was disconcerting and you'll have to take extra caution to look at the markings on each switch.
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