iFi Micro iTube2 Vacuum Tube Buffer and Preamplifier

Average User Rating:
4.8/5,
  1. Bansaku
    5.0/5,
    "Classic SET Tube Magic: Redefined!"
    Pros - It brought the magic back to my music!
    Cons - Absolutely nothing!
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    Intro


    iFi is a brand born from trickle-down technology, licensed from AMR with one simple mission: To provide the absolute best quality ‘Bit-Perfect’ audio from computer generated sources . All iFi products proudly boast clean Class A analogue circuitry with absolutely no digital signal processing; The signal stays true to the source throughout! Since iFi broke into the scene in 2012 they have been making huge waves in the audiophile community, offering products who’s performance is on par with their beautiful, modular design! Every product has been carefully engineered for perfect symmetry and synergy with one another, allowing the user to custom tailor their stacks to their desired needs.

    As part of the original micro line, the micro iTube was an incredibly popular product. Described as the ‘Swiss Army Knife’ of components, the original micro iTube boasted a tube buffer (0dB or 6dB gain), pre-amp with analogue volume control (0dB or 6dB gain), 3D enhancement effects for speakers, as well as ‘Digital Antidote Plus’, a feature designed to take the “digital’ out of the source and make it sound more ‘analogue’. For many, the sleek and sexy multi-functional micro iTube was hailed as something they never knew they wanted, let alone needed! Building upon it’s success, iFi audio took everything that made the micro iTube great and started over, keeping only the NOS GE 5670 tube! Heavily influenced by their flagship product, the iCAN Pro, built from the ground up using trickle-down technology the micro iTube2 was born!

    Disclaimer/Acknowledgement

    The micro iTube2 was sent to me on loan direct from iFi Audio USA in exchange for my impressions and review. The words I write are my own and are honest, objective, and free of bias. I received no financial compensation for my effort, only the satisfaction of trying out a quality product for a few weeks.

    More importantly, I would like to thank Lawrance over at iFi Audio for providing me the opportunity to review the micro iTube2. Out of the blue I was sent a message here at Head-Fi asking me if I would like to spend some time with their newly released micro iTube2! As a proud owner of iFi products, how could I say no? However, due to popular demand and higher than expected sales by the time our e-mails had crossed back and forth, there were no units left to send out! No worries as I was asked if there was another product that I would be interested in trying out until the inventory levels for the micro iTube2 had been refreshed. How awesome was that? I chose the iPurifier2, and if your would like to read what I thought of the device, click here. So anyway, a short time later a review unit was ready to be shipped out, and here we are today, micro iTube2 in hand. You know what they say, “ All good things come to those who wait. “… or perhaps “ Shut up and take my money! “ might be better suited in this case!

    About Me

    Born in 1978, I grew up in a family consisting of musicians, broadcaster/sound engineers, and amateur DJs. I always had a deep appreciation and understanding of both music and sound. I was further educated in this self interest after taking courses in both basic electronics and Sound: Electro-Acousto - The Path to Golden Ears. While I believe a listener’s preference in sound is subjective, the science behind it is not. I am not swayed by buzzwords, hype, trends, brand recognition, or big numbers on charts. Opinionated as I am, my words are not only objective but honest. I view all criticism as constructive, as long as it is sincere.

    Specifications

    Tube: N.O.S. G.E. 5670
    Maximum output: > 7.75V (>+20dBu)
    SNR: 119dB(A) re. 2V, buffer, 0dB Gain
    DNR: 131dB(A) re. +20dBu, buffer, 0dB Gain
    THD & N: < 0.009% (re. 2V, buffer, 0dB Gain, A- weighted)
    Frequency Response: < 10Hz -to > 200kHz (-1dB) 20Hz – 20kHz (+/-0.003dB)
    Input impedance: 1M ohm Direct Tube Buffer 100k ohm Pre-Amplifier with Volume Control
    Output stage output impedance: <1 ohm
    Corrected output impedance: <150 ohm
    Input voltage: AC 100-240V, 50/60Hz
    Power consumption: <4W idle, 10W max
    Dimensions: 175(l) x 67 (w) x 28 (h) mm
    Weight: 278g (0.61lbs)

    Features

    - Anodized in ‘titanium’
    - Analogue Volume Control
    - iPower (15V)
    - 3D Holographic+ matrix for speakers (off/3D+ width/3D+ 30°)
    - XBass+ for speakers (off/6dB 20Hz/12dB 20Hz)
    - Tube+ (SET/Classic/Push-Pull)
    - Tube buffer (0dB/9dB gain)
    - Tube Preamp (0dB/9dB gain)

    Brand-new PCB, Direct-Coupled for purest signal path

    The iTube2, in-line with the latest iFi products, is ‘Direct-Coupled.’ This means no output coupling capacitor for the purest, most direct signal path.

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    Reference class parts quality

    The iTube2 employs Japan TDK C0G type capacitors. These are complimented by Japan Panasonic ECPU Film Capacitors explicitly designed for audio use with extremely low distortion (<0.00001% @ 1V/10kHz).

    The iTube 2 also uses ELNA SIlmic capacitors. These and other parts are only found in components with an extra ‘0’ to the price.

    The proof is in the listening. The best tube buffer/pre-amp out there just pulled even further ahead.

    ‘Magic’ of SET, Push-Pull or Classic Tube sound

    In the ‘magic of tubes’ listening stakes, the iTube2 offers the listener the choice of different key sonic signatures:

    – a Single-Ended Triode power amplifier;
    – a classic tube amplifier.
    – a Push-Pull tube power amplifier;


    Just to note from the iFi team – there is no ‘right’ setting. We advise you to set according to your systems synergy and your listening preferences.

    XBass+® matrix for Speakers

    XBass+® for Speakers is quite different to its sister technology XBass+® for Headphones. The only similarity is in philosophy as the ability to enhance your Speaker listening is quite different to enhancing Headphone listening.

    The former gives each and every audio system adjustable levels of bass control to enhance listening enjoyment through speakers that have limited bass extension. We have taken great care to ensure no degradation in sound quality occurs.

    20 Hz (6dB): For speakers missing only the lowest bass notes (below 40Hz).
    20 Hz(12dB): For speakers missing some bass notes (below 80Hz).
    OFF: XBass+ switched out

    3D Holographic+® matrix for Speakers

    The latest 3D Holographic+ matrix for Speakers offers something quite special. It takes high-end systems to another level of performance. It was drawn from the original ground-breaking work of Alan Blumlein, the ‘father of stereo.’

    Firstly, it corrects the fundamental spatial distortion in recordings. And secondly, it increases the width of the soundstage beyond that of the speaker placement.

    30˚+ : This matrix adds an extra 30˚ to redress the narrow placement of speakers (eg either side of a PC monitor).
    + : This matrix recreates original ‘width’ of the soundstage and is the recommended DEFAULT setting.
    Off : 3D+ switched out.

    Accessories


    iFi includes everything that is needed; High quality RCA interconnects (+1 for being purple!), an L-adaptor for the iPower to keep the connection flush against the unit, a handy super tiny flathead screw-driver to adjust the DIP switches in the event one’s fingers are unable to toggle them manually, a pad of rubber stick on feet, specification and warranty cards, and for good measures an anti-moisture pack.

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    Packing

    I am a huge fan of minimalistic yet functional packaging that gives the consumer the sense that they have purchased a quality product, and the iPurifier checks off all boxes on the list. Much like iFi’s other products, the iTube 2 comes in a white, almost Apple-esque sturdy box made of 100% recycled materials free of any toxins that meet environmental standards. The device is nestled in a sturdy cardboard tray with the accessories neatly packaged in compartment underneath; There is no wasted space holding nothing but air, rather only what is needed. A big ‘“hats-off” to iFi for thinking of more than just their bottom-line!

    Build/Design

    Measuring 158 x 68 x 28mm and constructed of recycled CNC aluminum, from a build and design perspective the micro iTube2 is purposefully identical to the rest of iFi’s micro line. Every component of the micro line are designed to be stacked with one another so consistency and conformity is a must for both logistics as well as aesthetics. Like it’s line-mates, the micro iTube2’s anodized shell is titanium in colour (albeit a slightly darker shade) with identical body lines and curves. The front and back plates are held together with 4 small screws and adds a nice utilitarian look without being too cluttered or gaudy in relation to the controls.

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    Growing up in the 1980’s I am very familiar with analogue volume potentiometer and toggle switches. Rarely have I encountered a more smooth, solid, and balanced pot as I have on the micro iTube2. Saying that the volume pot is of high quality is an understatement as it not only possess perfectly smooth rotary tension, to my ears there is virtually zero channel imbalance when turned to the lower quarter of the dial! The recessed chromed toggle switches are of equal quality, and possess a smooth yet tactile rigidity. The toggle action is solid; Moving the switches up and down was easily done with absolutely no wiggle or play detected while in action or in place! Without a doubt, much like every one of iFi’s products, the micro iTube 2 is a quality product that is built to last!

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    The text on the micro iTube2, both on the faceplate as well as the underside, was easily discernible despite being essentially grey-on-grey. Whether the environmental lighting was akin to a man-cave, recording studio, living room during high-noon, or simply nothing more than the LEDs of a computer monitor, no matter the situation I never had readjust my viewing angle to read what operation I was trying to achieve. This can not be said about iFi’s previous generation and even more recent products. From my own observations, the darker titanium anodized coating and the darker colour of the graphics give both a better contrast under a wide range of lighting as well as helps alleviate the reflection across the surfaces. Owning the original micro iDAC (mid 2012) as well as the recently released micro iCAN SE (late 2015), I can tell you first hand that the new colouration is a welcome change.

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    Pre-Amp and Buffer

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    While loaded with a plethora of features, the micro iTube2’s basic functionality can be summed up as either a pre-amplifier or a buffer (SET filter). So what is the difference and which should you choose to use for your set-up? Before I answer some basic understanding of why a pre-amplifier is needed. In an audio system the input circuit is the electrical audio signal recorded on media or running in from a microphone or pick-up. Its load is modifying the output circuit and applies a varying resistance to the output circuit to re-create the voltage fluctuations of the original audio signal. In most amplifiers, this load is too much work for the original audio signal. For this reason, the signal is first boosted by a pre-amplifier, which sends a stronger output signal to the power amplifier. The pre-amplifier works the same basic way as the amplifier in that the input circuit applies varying resistance to an output circuit generated by the power supply.

    A good preamp is like Lingerie. It makes the content and playback more revealing, allowing the man a deeper insight into the source material, and paints a vivid seductive picture of the artists original intent, and keeps him thirsting for more... A good preamp titillates the listeners senses!

    I hope this post explains things as it really matters, in a format more understandable to the lay audience than all the previous needlessly technical and geeky explanations.

    --G0bble

    - It can boost a low signal when your source and destination are far away from each other. A pre-amp can be beneficial in minimizing the noise that is picked up on the line to the power amp.
    - It can clean up the signal. If you were going to be performing some filtering on a signal (i.e. a vacuum tube), the filtering elements can add noise to your system and by adding a preamp the noise is minimized compared to the signal.
    - It can adjust the signal. Power amps can be more difficult to directly change the volume on while a preamp is much easier. So you can change your volume on the preamp and have a fixed gain on the power amp.
    - It can act as a simple buffer between your source and the filtering equipment.
    - Impedance matching. In electronics, impedance matching is the practice of designing the input impedance of an electrical load or the output impedance of its corresponding signal source to maximize or minimize signal reflection from the load. In other words, it takes the signal and optimizes it for the receiver.

    Now that we have a basic understanding and uses of a pre-amplifier defined, why use the micro iTube2 as a buffer? Simply put, the buffer has fixed output and the pre-amplifier has variable output; It all comes down to one’s specific application and whether or not the volume pot is needed. If you have no use for a pre-amplifier and simply want to add in the magic of class-A SET into your system while implementing 3D Matrix and XBass, you would want to use the micro iTube2 as a buffer. If any of the above uses of a pre-amplifier is applicable to you, using the micro iTube2 as such is the way to go.

    Break-in Period

    While there is no mention of a break-in period in any of iFi’s documentation, the recommended industry standard for electrical devices and components is 40 hours. Personally, while I do tend to wait until 48 hours of real word use before making any written impressions, it is done not so much to listen for any changes in the sound rather to make sure the device and it’s components are operating correctly. From my own experience in both my home life and profession, if any issues arise they are usually detected early in the device’s life. Much like with the micro iDAC and iCAN SE, the 48 hour break-in period with the micro iTube2 yielded absolutely no change in sound, nor did I encounter any perceived problems or issues, a sign of a well engineered and constructed product!

    Tube Warm-up

    Don’t expect to turn the knob and immediately start jamming out to your tunes. Due to the nature of the tube itself, a warm-up period is required when the micro iTube2 is first powered on. Essentially, the inner workings of the tube has to reach an operating temperature before any sound could be heard. This time will vary depending on the ambient temperature, but it is not long at all. From my experience, the micro iTube2 will reach the optimum temperature in about 1 minute, give or take. Once fully heated, the device itself will get warm to the touch. This is normal and in no way will harm the device nor the components near by; The aluminium shell does a great job at absorbing and dissipating the heat evenly.

    Initial Impressions and General Thoughts

    Being old enough to remember the transition from analogue to digital, I had a longing to hear my music without the edge and sharpness created by todays digital equipment as I once did. A few summers past I went on a journey of (re)discovery and purchased several tube buffer/pre-amps from eBay ranging in price between $50 and $200 CND as well as every type of compatible NOS tubes I could get my hand on (including the GE 5670 JAN, my favourite). It was no co-incidence that at the time I had been reading up on the original micro iTube with an end goal of bringing life back to my digital recordings. My experience could only be described as lacklustre. Given the absence of such devices in my signature and profile, as well as my lack of postings here at Head-Fi, it goes to show just how much I truly though of the cheap Chinese tube kits. While they all worked as advertised, each underperformed. In terms of tube buffers/pre-amps most suffered from some form of clipping, attenuation, distortion, and noise. Sure, they did smooth things over and there was some fun to be had with shaping the sound, however in regards to the “tube magic”, there was none. While I did get a flavour of each specific tube(s) I rolled, the sonic effects could be better emulated using AU/VST plug-ins and a quality amp. Then there was the cheap components used and the sub-par construction… Needless to say by Christmas of that year all were sold, and I went back to drooling over the micro iTube.

    A lot has changed in terms of my equipment between then and now, most notably my switch from the likes of Teac UD-H01, Audioengine D1, and SoundBlaster E3 to an exclusive iFi stack. My search for a smooth and detailed analogue sound was pretty much over as I was more than content with micro iCAN SE/DAC combo. After my experience with less than great tube buffers/amps and experiencing the class-A TubeState technology found in the updated micro iCAN SE (amongst others), I had come to the conclusion that a device such as the micro iTube2 wouldn’t be beneficial to my set-up, and if anything detract from the overall transparency through tube distortion. I couldn’t have been more wrong! Once integrated into the chain, it took but one song for me to realize that the micro iTube2 was more than a well engineered class-A SET pre-amplifier and tube buffer, it was magic!

    The micro iTube2 came shipped with default setting of 9dB: pre-amp mode, and while that would be the eventual setting I would leave it set to, initially I changed it to 0dB: buffer mode as I was mostly going to be testing the unit in my iFi stack and headphones. Wearing my PSB M4U 1, the very first thing I noticed was the perfectly black background, and I do not mean it simply did not introduce any background noise, no, I mean it crated a vacuum like silence free of any discernible noise! I honestly thought the tube had not heated up enough and therefore I simply was not hearing the noise, yet. 10 minutes passed and at idle I still was hearing absolutely nothing! Switching the buffer and pre-amp gain to 9dB yielded impressively similar results. I used my PSBs for this test as they provide the absolute best seal I have encountered in a headphone and thus allows me to hear, if present, any garbage coming down the chain, and I encountered nothing of the sort. Even with both my BA and dynamic driver IEMs, at 9dB gain and maxed out volume of the micro iCAN SE, I could detect no audible noise. It was not until I switched the gain on the micro iCAN SE to 24dB that I started to hear a less than perfect black background. However, regardless of the headphone, under no circumstance would I, or probably anyone for that matter, ever be needing 33dB of gain on an iFi stack outside of attempting to amplify a phono source, and iFi makes the micro iPhono2 for that application!

    Plugging in my HD 600, I loaded up Audirvana and pushed play, on random, because that’s how I like to roll! At this point I decided to throw all my previous experience and expectations with tube buffers out the window. Judging by the iFi products I own as well as what I was hearing (or rather not hearing), I knew the micro iTube2 will be a world apart from all I have tried before. What I was not prepared for was the magic that was about to be unleashed! With 3D and XBass off, I started with the ‘Classic SET’ Tube+ setting. First up was Dukas - The Sorcerer’s Apprentice as performed by Telarc’s Cincinnati Pops Orchestra, and I was floored! Every note was rendered with such smoothness yet possessed enhanced texture as well as greater focus, all while maintaining transparency with no loss of detail! Moving along to the ‘Classic Tube’ setting, I was immediately greeted with the familiar classic sound of the GE 5670 JAN, un-like I have ever heard before; The micro iTube2 fully unleashed the true potential of the GE 5670! Adding in both warmth and crispness, the soundscape became more expansive, full of weighted air that allows sound to bloom with a sonic delight! What can best be described as “ the best of both worlds “, switching to ‘Push-Pull’ proved to be the setting that many times caused my eventual drifting into hours of what can only described as meditative audio-nirvana!

    Lets go over some of my overall impressions of the Tube+, shall we? As previously stated from iFi above, there is no right or wrong setting to use, and is completely dependant on both the listener’s preference as well as the source. While I completely agree with that statement, often finding myself switching modes depending on what headphone I am wearing as well as what track is currently being played, the actual naming of each setting, technically, is somewhat ambiguous. Class-A SET power amplifier, classic tube amplifier, and a push-pull tube amplifier, all describe the basic fundamentals of a device such as the micro iTube2. Reading them, I find myself saying “ Uhm, yes? ”. I do however understand iFi’s reasoning behind their labeling, and I will do my best to describe what I think each of the three settings is trying to achieve.

    Classic Single-Ended-Triode Power Amplifier: This setting can best be though of as passthrough or neutral, with an added bonus. The classic tube effects are the least prevalent on this setting, and the source retains most of it’s original sound signature. However, this setting can also be though of as the original micro iTube’s ‘Digital Antidote Plus’! While the overall presentation of the source remains virtually unchanged, the sound now possesses an very analogue smoothness to it! There is added weight and warmth to both the bass and midrange, the treble has an added layer of crispness, and there does seem to be greater focus, but in no way would I describe it as adding colouration to the sound. Simply put, there is no frequency deviation from the source, only the addition of even ordered harmonics, or saturation, to the sound.

    Classic Tube amplifier: The name of the setting says it all, and is the most prominent of the three. While I could use clichéd terms like expansive, weighted, warm yet airy, powerful and crisp, and I would not be wrong in doing so, this setting is so much more, and the best way of describing what I hear would be smooth-voluminous-analogue-tube-magic! As previously mentioned, this setting literally brings out the true potential of the GE 5670 JAN and punches you in the ears with it’s breathtaking sound!

    Classic Push-Pull amplifier: 50% SET, 50% Classic Tube? Like Classic SET, but in hyperdrive, or perhaps Classic Tube on steroids? Actually, I tend to think of this setting more as the-complete-sound! Saying it’s the best of both world’s is simplifying things too much. I would best describe the sound as breathtaking, unbridled, powerful, pure class-A SET perfection! Or magic… definitely magic!

    In regards to the 3D+ and XBass, I won’t be giving any thought and impressions in this section of the review. They are simply not applicable to me. The vast majority of my listening involves my headphones and my iFi stack, and this portion of the review is focused around just that. 3D+ and XBass are specifically designed with the use of loudspeakers, not headphones. Sure, one can toggle either and it “may” sound pleasant with their headphones, but let it be known that 3D+ and XBass on the micro iCAN (SE/BL) do a far greater job at their respected functions for headphones than the micro iTube2. In terms of their basic functionality, they are pretty straight forward and iFi does such a great job defining them that any words of mine would be nothing more than redundancy. I will however be covering numerous application in the upcoming paragraphs, which will include the use of both features. Much like Tube+, both redefine what I thought was possible in such a compact device, and will not be overlooked!

    To end off my initial thoughts and general impressions, I was correct in forgetting what I knew, or thought I knew, of how a tube buffer should perform. Introducing rich saturation and unadulterated musical bliss, track after track, no matter the genre, the micro iTube2 exceeded my expectations in which I experienced no negative qualities whatsoever! From both my readings as well as personal experience, adding a tube buffer into the chain will always have a give/take relationship with the sound. For example, while the bass may become more defined it can lose impact, or the soundstage may become more expansive but at the same time the treble can become more harsh. Not so with the micro iTube2! There was no perceived colouration to the sound, no audible attenuation/accenting, no clipping, basically zero negative distortion! It mattered not the Tube+ setting nor the song played, the micro iTube2 simply enhanced the sound to a musical level my ears have yet to experience up until now!

    Impressions (Application Specific)
    * All testing was done using a variety of controlled A/B and sources that would be too numerous to list, as well as add in unneeded bulk to the review

    Audirvana—> iPurifier2—> micro iDAC—> micro iTube2—> micro iCAN SE—> any headphone

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    To start off this section, lets begin with synergy. First, a definition: Synergy is the interaction or cooperation of two or more organizations, substances, or other agents to produce a combined effect greater than the sum of their separate effects. From their aesthetics to their features, the whole of iFi’s micro line of products are designed to operate in perfect synergy with one another. While the micro iTube2 is a multifaceted device, it’s main functionality is to be stacked onto other iFi devices, meaning there is the ability to mix and match settings for headphones. This is where synergy comes into play. Regardless of what combination I tried, there was never an instance where I got a sense that the features of the micro iTube2 were conflicting with that of the micro iCAN SE, quite the opposite in fact; Every feature was completely complimentary!

    Engaging XBass in no way muddied the sound, nor did it accentuate or detract. Bass, no matter on high or low boost, remained incredibly controlled; The micro iCAN SE kept an absolute grip on the low end, regardless of the Tube+ setting on the micro iTube2! I am not sure how, but the tube magic introduced by the micro iTube2 enhanced XBass to a whole new level of ‘wow’! Both texture and definition were kicked up a notch, a sign no sluggishness has been introduced, while impact and sub-bass alike received added saturation and weight. One major take away to note would be that in no way does the micro iTube2 boost the low end, it simply adds what was missing.

    With 3D+ engaged, I half expected that engaging 3D+ high on the micro iCAN SE and using ‘classic tube’ or ‘push-pull’ would result in an overload of soundscape expansiveness, like engaging Dolby Headphones and SRS at the same time; yuck! Well, things got real! Much like XBass, it mattered not which combinations I tried, the result was nothing but a complimentary enhancement! The sound remained coherent with the effects of both devices melding into an effect that seemingly makes the headphone disappear!

    Overall, I am more than impressed with the absolute perfect synergy between iFi’s products! Call it what you want, magic or great engineering, when it comes to the mixing and matching of desired enhancing features à la carte, there really is no wrong way to go considering there are zero negatives to be had! On there own, every toggle function outperforms many over-engineered/over-priced products, as well as ones who’s selling points overshadow their actual performance. Add in the fact that you can combine multiple toggles to shape the sound to your desire, all while the stack maintains absolute control of the sound, is nothing short of impressive! Or perhaps even magical!

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    Audirvana—> iPurifier2—> micro iDAC—> micro iTube2—> micro iCAN SE—> Sennheiser HD 600, AKG Q701, Grado SR60e, PSB M4U 1, Meze 99 Classics/99 Neo

    The Sennheiser HD 600, AKG K70X, and Grado Prestige series are probably the three most popular open backed headphone lines in current production, thus the headphones used for this section are a good representation of what the average end user may own. Closely resembling the sound presentation one would expect from a loudspeaker, their open design gives the user a more natural listening experience, but they are not without flaws. One common complaint myself and other have with open back headphones in general is the subdued bass impact, weight and resonance. Regardless of how well textured and defined it may be, without having and enclosed system such as a closed backing (or in respect to a loudspeaker, a room) the low end tends to flutter out and suffer due to the lack of reflecting surfaces.

    Using the Classic SET setting, without engaging XBass on the micro iCAN SE, the micro iTube2 re-introduced all that was missing from the low end to both the HD 600 and Grado SR60; Impact and weight. Admittedly, for the Q701 I did have to engage the lowest XBass setting to achieve satisfactory results, but hey, that’s what the feature is there for, and now the bass has, what I consider, proper impact and weight! For both the SR60e and Q701, another common issue many have is the upper midrange and lower treble. While well extended, for some this range of frequency can sound too hot, too piercing, and thus fatiguing, and I am no exception. The micro iTube2 manages to smooth over the troublesome regions, providing a far less fatiguing sound yet does so with no loss of resolve or detail! Try as I did, I was unable to detect anything missing from the music, nor did I encounter any drop out or roll off when playing test tones/sine sweeps. One thing I did find with all three headphones is that overall the sound stage seemed more contained, more defined. What I mean by that statement is that I am hearing more of the track’s recording environment(s), something that is more prevalent in closed back headphones, yet the natural openness has not been diminished!

    Moving along to the closed back headphones, the PSB M4U 1 and both the Meze 99 Classics and 99 Neo all share a common sound signature; Slightly elevated yet well extended bass and controlled bass, silky smooth liquid like midrange, and a crisp, fatigue free detailed treble that offers the perfect balance of sparkle and air. They are wonderful performers and very well received within the community. Keeping with SET and starting with the PSBs, I immediately noticed how much more relaxed the upper mids and lower treble are when at a higher volume. On certain tracks at higher than normal listening levels this region can become somewhat strident for the M4U 1. Like magic not an once of detail is lost, yet much like the afore mentioned Grado and AKG this region of the frequency response became less fatiguing! Bass weight and impact became more apparent while the lower midrange was enhanced with greater texture and focus! Both Meze faired equally as well in that micro iTube2 did nothing but enhance what was already great sounding headphones! Texture popped with a greater focus throughout, bass became more weighted yet remained controlled, and the treble received a good does of a natural sense of air while maintaining it’s crisp nature!

    While the micro iTube2 essentially enhances the sound of both closed and open back headphones in a similar manner, it is interesting to note that in regards to the sound scape the behaviour is the polar opposite. For open backed headphones, the micro iTube2 seemingly adds a greater sense of the room. While maintaining their openness, there is a far greater focus on the boundary of the sound, much like a closed back headphone. It is the reverse for closed back. Because of the nature of their design, there is no missing sense of boundaries as the sound is enclosed within the cup. What the micro iTube2 adds is a greater sense of air and space to the soundscape, giving way to a sound more akin to a open air headphone! Impressive!

    Both the classic tube and push-pull settings yielded results that went beyond my expectations, regardless of the headphone. While the bass became more solid, even coherent overall, what impressed me the most is the return of resonance… kind of. SET brought greater bass weight and impact, but classic tube and push/pull introduced a large, voluminous sub-bass! In no way is it boosted, rather saturated and expanded! Adding weight and air to the midrange, texture is brought to a whole new level with much greater focus and resolve. Treble also gets a boost thanks to the the increased saturation, creating a more crisp and defined upper range without negating any sense of natural air! Lastly, the soundstage became more focused and expanded, almost as if invisible boundaries were created thus providing a greater sense of imaging, yet still maintained the openness the style of these headphone produce. I have always been quite content with the sound of these headphones, they are all well reviewed and respected, but the simple inclusion of the micro iTube2 brought them to a whole new level of audio excellence! Nothing sounds boosted nor out of place, simply enhanced in a natural and organic way!

    Before I round off this section, I have to give special props to both the HD 600 and 99 Classics. Earlier I talked about synergy, well, the HD 600 and the iFi stack are the epitome of the word! I don’t think it’s too far fetched to assume that the folks at iFi have this headphone readily on hand, nor would it be to likewise assume the HD 600 is the final step in their testing. I am having trouble finding words to describe their relationship, other than they are a match made in Heaven! Unadulterated, pure music magic! Including the micro iTube2 into my stack has not only made me appreciate the HD 600 to a greater level, it has re-ignited my love of these legendary headphones!

    Not to be outdone by the HD 600, the Meze 99 Classics and micro iTube2 share perfect complimentary symmetry! Unlike speculation about iFi and the HD 600, I know the folks at Meze have iFi products sitting at their desks; I have seen the pictures! They don’t lie, and neither does the pairing of the two. Simply put, the micro iTube2 enhanced the “classic” of the Mezes and took the already phenomenal sounding headphone to the next echelon of listening enjoyment! Well done guys!

    Audirvana—> iPurifier2—> micro iDAC—> micro iTube2—> Yamaha HTR-6040 Natural Sound receiver —> Klipsch WF 34 Icon loudspeakers

    Over the years I have gone through great lengths to bridge the audio from my computer to my home theatre system and achieve optimum sound reproduction. The problem stems from the distance between the two, and how to connect them without introducing interference. Most people, like myself, will simply use a standard RCA that is long enough to reach, which is fine for short runs, but once the distance spans greater than 15’ there is a good chance that the signal will start to break up and artifacts introduced. Buzzing, hum, clicks, noise, fuzz, even radio stations, I have heard it all! This is why XLR or balanced cables were created. I however do not have this luxury. My solution to achieve a clean, uninhibited signal was to purchase a TosLink (optical digital) booster and use a 20’ optical connection from my computer to my receiver. This means that over the years I have missed out on using my Audioengine, my TEAC, and now my micro iDAC, and relied solely on the Yamaha’s AKM DAC. Enter the micro iTube2!

    When it came time to test the micro iTube2 with my home stereo, I was admittedly at a loss as to how I was going to get the audio from the iFi stack to the receiver. Do I temporarily move my whole computer closer? Maybe chain a few powered USB hubs together and move the iFi stack closer? Then it dawned on me, and I felt pretty silly for not realizing this earlier. By design, a pre-amp is a signal booster! So I now had a solution: bridge the micro iTube2 between the micro iDAC and my Yamaha receiver using 2 short RCA cables! Duh! So after I got over my blonde moment I dug out a pair of 10’ audiophile grade RCA and made it happen. This actually worked out great as my listening position just happened to be at exactly 9’ away from both my computer and my stereo, meaning the micro iTube2 was able to sit on my coffee table, thus allowing me to easily select and control the various settings! Yeah, I now have thick RCA cables running across my floor, but it it is a small and temporary price to pay for a clean, unhindered signal!

    The Klipsch WF 34 Icons are not only perfectly angled to 30° but perfectly spaced and distanced from each other and the walls. I opted for 3D+ and XBass to be disabled, and started things off using nothing more than SET. The moment I pushed play the inclusion of the micro iTube2 was noticeable; Smooth, warm, inviting! My Icons never sounded so sweet, so analogue! Bass became more impactful, the midrange gained a nice layer of warmth leading way to fantastic texture, and the treble completely smoothed over becoming less fatiguing yet more detailed and focused! I always thought the Icons were detail monsters before, but SET added such beautiful saturation that I am hearing not detail that I have never heard before rather hearing detail presented in a way I have never experienced before!

    Things were starting to look very promising, so I decided to switch on XBass 6dB gain. I have to note, the WF 34 Icons only reach down to 50Hz. Bass is solid and very impactful thanks to their kevlar reinforced fibre glass drivers, but it never really gave me that deep inner body sub-bass rumble. Essentially, my feet on the floor could feel the bass, my body could not. Engaging XBass is a whole different ball game! If I were to use the receiver’s bass tone control and give it a boost of 6dB the result is merely louder bass, while engaging XBass seemingly fills in the gaps and enhances the sub-bass to a visceral level! Wow, I am actually ‘feeling’ the sub-bass throughout my body! What I find very interesting is that with the receiver’s bass boost, anything that hangs on my walls will start to vibrate, however XBass lets me feel the music yet my walls remain unaffected! How is this possible!? Magic?

    Moving along to 3D+ toggles, as the loudspeakers are angled to 30° selecting 30°+ would not be beneficial. For poops and laughs I did try, and the result was an over-focus and narrowing of the sound field, much like if the loudspeakers were toed in at a greater angle, and did not sound that pleasant. However, engaging the 3D+ was nothing short of amazing! I expected this setting would simply add greater width to the sound field, and it does in a way that sounds extremely natural and not forced. What I was not expecting is how 3D + seemingly pulls the sound away from the speakers and extends it outwards! I have heard many 3D enhancers both software and hardware driven, and they all sound like a DSP. 3D+, simply put, organically enhances the soundscape to a degree that I can’t put into words other than it has to be heard to be believed!

    Keeping with 3D + and XBass 6dB, the real magic began once I toggled Tube+ from SET to Classic. The first track to play was Nah Neh Nah - Vaya Con Dios and my jaw hit the floor! I literally had one of those moments where the hair stands up on the back of your neck, eyes start to water, a chill of excitement flows through your veins, and you forget to breathe! Such life, such flawless beauty, such emotion and excitement! My senses were ignited, and I was in another dimension completely detached from this reality! It was like I was placed front and centre in a cabaret hall with a private performance of Vaya Con Dios for only myself! Every nuance of the sound came to life and was brought to the forefront. Nothing sounded coloured, bolstered, or distorted negatively; Simply natural, organic transparency! Just…wow! In all honesty, I had to mellow out and compromise with Push/Pull for a while after; Tube+ was just too darn good!

    To sum up this section, all I have to say is that the micro iTube2 enhanced my home stereo to a level I never thought was technically possible outside of purchasing all new components! Call it wizardry or a technological marvel, I have upgraded both speakers and amplifiers to a much lesser effect than what the micro iTube2 adds to my music, bar none! iFi really knows both their engineering and what is lacking in todays modern home audio solutions, and redefines what I thought possible in a SET tube pre-amplifier. Hearing what I have heard there is no going back to the old way; My ears will not allow it!

    CPU—> iPurifier2—> micro iDAC—> micro iTube2—> Lepy LP-2020A —> Mission Model 80 monitors

    The Lepy and Mission combo fed from my PC’s on-board audio is what I use for my desktop audio set-up, and is used almost exclusively for watching streaming videos. It’s not fancy but it gets the job done by providing decent performance while taking up the least desktop space. Including the micro iDAC and micro iTube2 into the mix really stepped up the sound, by a large margin! It was like a upgraded my amp! Simply by using nothing more than SET toggled, the first thing that became apparent was the smoothness of the rendering. The digital harshness typical with class-D amplifiers dissolved, leaving only a classic analogue sound! Of course, switching things up and selecting the other two Tube+ settings yielded expected results; Enhanced bass, greater texture, and a more open soundstage!

    Normally, the Missions are angled to 30°, so to test out the 3D Holographic+ 30° option I moved them flush against my monitor. I must say, the implementation of the 30°+ setting is absolutely spot on! To my ears, I heard very little deviation of the soundscape between having the speakers naturally placed at 30° or with the 30°+ toggled. Everything sounded natural and organic, and not forced; Very impressive! Moving the speakers back to their normal angle, I engaged 3D + and what I heard was identical to my WF 34 in that the sound, like magic, seemingly detached itself from the cones and expanded outward! While the effect was not quite as prevalent as my loudspeakers, it did give a greater sense of size to the monitors as well as the accompanying sound stage!

    Not to overlook XBass+, but for my application and use of this set-up I found this option to be not needed, and in all honesty too much. Engaging 6db was enough to cause distracting vibration of my desktop, and at 12dB gain the amp starts to show signs of distortion. I will say this though, compared to the bass pot on the Lepy, XBass+ 6dB does a far greater job at enhancing the bass providing a clean, impactful sound without sounding like a cheap inclusion as with the LP-2020A!

    (Hitachi 46” LED) HDTV—> micro iTube2—> Genius GX 1250 amp—> Nuance 101 monitors

    For many years now this has been the setup I use for TV viewing. It is a nice combo, with the 20W class A/B amp providing decent power and sound to the 100W monitors. The sound is miles ahead of the TV’s built in speakers, and destroy what a sounder could produce! Unfortunately, due to their large size as well as the overall size of my sunken living room in relation to my Klipsch loudspeakers, the placement of the monitors have to be flush against the TV. I could angle them to 30°, however only 1 person on the couch, me, would receive the benefit of the speaker’s positioning. A simple flip of a switch would remedy this issue!

    The TVs I have owned in the past all had some sort of SRS 3D, Dolby Virtual Surround, or some form of generic virtual surround, and most were, at best, neat sounding. They were somewhat effective, but essentially amounted to nothing more than a gimmicky selling point. 30°+, simply put, not only brought the wow factor to the monitors but put all other implementations to shame! Much like with my desktop setup, the monitors did indeed sound like they were in fact angled at 30°. Unlike my desktop setup, because of the 9-10’ distance between me and the monitors the perception of the effect was much greater; No matter where I was seated on the couch (or even standing in the room) the effects could be heard.

    Just to note, I did engage both XBass and 3D + to give them a try. While latter setting magically pulled the sound out and away from the cones, the effect was not as satisfying as 30°+. XBass, once again, was not too applicable in this setup as the monitors have the capacity to reach down to 20Hz. Engaging 6dB XBass gain was fun, 12dB probably angered my neighbours, but essentially both are not needed. As with anything, YMMV. In this particular setup 30°+ was enough to bring a more than satisfying TV watching experience.

    iPod Tough 6th Gen.—> micro iTube2—> Topping NX1s

    While the micro iTube2 on it’s own ins’t considered an OTG device, I thought I would include this combination as I know of many who use a portable music player in conjunction with a portable amplifier for use at their desks away from home. However for this chain I won’t be including my impression on the sound, as it would be redundant, rather speak about functionality and ergonomics. This is where using the micro iTube2 as a pre-amp comes in very handy.

    Having 3 devices in a chain that each has their own separate volume control can be a mess. Most digital devices have digital volume (duh), which means you have the potential to not only lose ‘bits’, but have a nasty step progression in it’s adjustments (i.e. one click up equals 3dB , then 2dB, then back to 3dB and so on). As well, most portable devices do not have a separate line out jack. To remedy this with use of an external amplifier, the headphone volume output will be set to max out on the source device. However, depending on the internal amp, you can also get double amping as well as a difference in the output impedance, which in most cases alters/degrades the sound. Not ideal if you want the absolute best out of your demanding headphones.

    Besides the plethora of enhancements and features previously covered, in this scenario including the micro iTube2 into the chain has two benefits. Firstly, because a pre-amp is essentially an analogue sound processor, it will take any signal and change it into something that is universally accepted. It matters not what signal is being fed in because the micro iTube2 will always output essentially an optimum amp friendly signal. This ensures that you are getting the absolute best quality of signal being passed through. Secondly, the pre-amp’s analogue volume pot can be used to adjust the output, forgoing the external amp’s. Besides ease of use, this also allows the user to adjust the volume to a much finer degree!This is very useful as most people who use a portable music player with an external amp also have the two devices banded together, making any volume adjustments rather cumbersome. Essentially one would set the amp’s volume once and use the micro iTube2’s analogue pot to make any further adjustments. Another benefit would be clutter and cable management between the devices. One could easily set the player/amp on top or beside the micro iTube2 hand have the leads snaking behind. Great for people like me who despises desk clutter and is constantly clearing away mess like I have OCD.

    iPod Tough 6th Gen.—> micro iTube2—> Sanyo MCD 950

    Just when I thought I had tried just about every combination available to me, while working on a project in the basement it dawned on me that I had overlooked my “work tunes”. Normally while at either my work bench or work out bench I listen to my Sanyo shelf unit being fed by my iPod. It’s a rather nice albeit 30 year old twin CD boombox featuring a dual woofer bass chamber. Back in the day this was considered top on the line, and has served my family well before making it’s way into my possession. I have to say, and not to my surprise, adding in the micro iTube2 turned this now vintage gem into an absolute delight to work to!

    Setting the boombox to flat EQ with the bass port on low, I started off with 3D + default and SET and was greeted with a pleasant warm expansion of the sound width. Not too bad in terms of achieving a smooth and expansive sound from such a unit. Switching things to 30° was a whole different animal! The sound seemingly detached itself from the unit and expanded outward! While the “sweet spot” was rather small, depending on the distance from the boombox, the effect was large enough to be heard several feet away regardless if I was seated or on my back. However, the combination of 30° and Classic Tube or Push/Pull blew my mind; The sound was now presented in what I can only describe as a 3D vacuum bubble! All I can say is wow, I didn’t think it were possible to achieve such a large expansive sound from a boombox! But what about XBass? Literally Earth shaking! By simply toggling 6dB, no matter what the bass tube was set to, the micro iTube2 brought power to the low end, so much so that I could feel the increased air pressure the ports were exhausting! Switching up to 12dB and having the chamber fully open was too much… for the wife upstairs… but oh was it glorious!

    All in all, I was pleasantly surprised at how much the micro iTube2 could enhance a boombox! While I am not too sure if I would continue using the combination, it is not because of the hassle of unchaining, then bringing the micro iTube2 downstair, and chaining things back together. Nope, it is because I don’t think I would get any work done! Having background tunes is one thing, but I wouldn’t get too much accomplished if I spent most of the time more engrossed in the music!

    Storey Time: Road Trip!

    Because iFi’s micro line of products share a common power requirement, I was able to make use of my 15V 2A battery power pack I whipped up for my micro iCAN SE and take the micro iTube2 on the road! As stated, my family is composed of musicians and professionals. While I have a good selection of gear to try, what my brothers have fills the gaps. The micro iTube2 is so versatile, I simply could not overlook the opportunity to try out and showcase to those who would appreciate what the device brings to the table.

    I do have to note though, there was some cable wizardry going on in connecting the micro iTube2 in most of the below cases, so for simplicity sake accept the chain and don’t think too much on the connectivity rather the results.

    Panasonic DMP-BDT700—> Onkyo M-3000R DAC/Pre-amp—> micro iTube2—> Onkyo M5000R Amplifier—> Proac Response D38 loudspeakers

    My eldest brother is the one who lead me down the path of the audiophile. Being a purist himself, his audio setups were a thing of beauty, both in topology and performance! What he currently has would be considered unattainable to the average enthusiast. Before reading any further, please, take the time to do a quick search of the components listed, maybe even read a few reviews. It’s cool, I don’t mind! This is his end-game, and hot diggity dog does it sound heavenly!

    I had originally popped in to play with his HTC Vibe and get a little VR time in before we had to attend a gathering at my parent’s, but I had ulterior motives; I HAD to try out the micro iTube2 on his dream system! I did not inform my brother I was bringing the micro iTube2, I knew he would have lectured me on how tubes are inferior to the semiconductor. He is the type who’s vast music collection is on CD, and will quote Nyquist whenever Hi-Rez audio is mentioned! So when I arrived I sprang the device on him and right away, and he started to state his opinion on why he doesn’t think a tube pre-amp would be in any way beneficial to the sound, as predicted. I told him to “ Trust me, this is going to be good! “ and proceeded to chain the micro iTube2 between the pre-amp and amp. His reaction was kind of meh, but he sat down in the sweet spot and indulged my demonstration.

    Starting off with Dire Straits Money For Nothing (original Brothers in Arms CD release), I set the micro iTube2 to SET and 3D + and pushed play. To receive the full effect, I stood behind him both listening and watching his reaction. As the melodramatics of the lyrics and synthesizer slowly faded in, followed by the powerful room filling drums and the eventual iconic guitar rift, I could feel the impact of the micro iTube2 immediately, and wow did it sound amazing! I really don’t like using this cliché, but it was as if I was hearing the song for the first time! The subtle nuances that were brought out, the full impact of the bass, the spacious room filling sound, and the organic smoothness can only described as (apologies for the crudeness) an eargasm! Looking down my brother had the all too familiar “silly grim”! I think he was impressed to say the least.

    As the song is over 8 minutes in length, about half way through I went over and turned down the music and asked “ Well? “ and he replied “ Turn it back up! “, and I obliged but not before toggling Tube +. His reaction was priceless. If anyone remembers the only BASF tape magazine adds, the one where there is a fellow sitting in an armchair in front of a stereo who is literally being blown away by the sound, that would be my brother! I must admit, returning to the spot behind him yielded a similar reaction! Holy H E double hockey sticks did it sound amazing! The next hour and a half was spent toggling various settings on the micro iTube2 and swapping out CD after CD, an exhausting effort, but it was so worth it and I really didn’t mind. A small price for perfection I’d say!

    Before we ended the listening session, it occurred to me that I had overlooked something; Removing the Onkyo pre-amp from the chain entirely! Relying on the Blu-ray player’s DAC and using the micro iTube2 as the pre-amp alone to the main Onkyo amplifier, my brother and I were more than impressed with the results. While there was a slight loss in refinement, the micro iTube2 managed to trade blows with the much, much more expensive pre-amp while enhancing and enriching the sound with blissful tube magic, something the latter could not! In the end, my brother made the remark that perhaps after he upgrades his computer’s graphics card, he may just pick up a micro iTube2 for himself. Nice! In my opinion, it is an absolute must have for him; It would be a disservice if he didn’t! Who needs flawless, silky smooth VR anyway?

    Jackson Flying-V—> micro iTube2—> Marshal Amplifier

    The next three sections are a result of yet another family gathering, this time at my 2nd older brother’s; I have three, one younger and 2 older, and they are all audio and tech enthusiasts in one way or another. Anyway, my younger bro had stopped by to pick my wife and I up to carpool to the event. As we were getting into the back of the truck, he turned and said “ Watch out for the guitar… “. I replied “ Guitar? Hmm… “ and it struck me, why not add a little bit of classic tubiness and bring the micro iTube2! I quickly ran back inside and grabbed the device. “ What’s that? “ he asked. “ Oh, you guys will see… “ I smirked!

    Shortly after we arrived and got settled in (beers and munchies) us brothers went down to the basement for a little rocking out to the game Rocksmith! My brother brought his Jackson because he could not stand to use the pack-in basic electric guitar, a move appreciated for those who would be playing. Myself, I am not musically inclined, so I would merely be a spectator. Connecting the flying-V to the small Marshal amp the rocking out begin! I did not immediately bring out the micro iTube2 as I wanted to get a good impression of the guitar/amp combo sounded on it’s own. After a few rounds, I decided it was time! During a quick vape break, I connected the micro iTube2 and awaited their return. Almost instantly my older brother noticed the device chained in and asked what it was. I told him it was a tube pre-amp and his eyes lit up! “ No way! “ he exclaimed as he crouched down to take a better look. My younger brother wasn’t sure what a tube pre-amp was, but we filled him in and he replied “ Cool! “, and the jamming out resumed!

    Starting off with only SET enabled, like magic the sound was transformed into what can best be described as a classic, warm, pleasantly distorted, fat sounding grittiness! We were all in amazement of the amplified sound coming out of the small amp! Toggling the Tube + and Push/Pull were equally impressive, both enhancing the airiness of the higher registers and adding organic crunchiness to the midrange texture. Adding the micro iTube2 transformed a modern run-of-the-mill amp into something more akin to an actual classic tube based amplifier. However what impressed all of us the most was the ability to push the micro iTube2 in terms of power without any break-up, something that is very common in classic tube based amps! You get all of the benefits without the usual disadvantages!

    In regards to both XBass and 3D+, neither setting really benefited the sound, and in some way just sounded weird or unpleasant. The latter really needs to be stereo for full effect, and XBass seemed to overdrive the sound too much resulting in negative distortion. I consider this in no way a shortcoming of the features as in actuality, in this application, neither really makes sense to use.

    Technics 1200 turntable—> micro iTube2—> M-Audio Project Mix I/O—> M-Audio M3-8 powered monitors

    Once fingers tired, it was time to move on to something less physically involving. Being a DJ, songwriter, and mixmaster, my brother has a pretty good set-up to record and master tracks. Of course, what professional in this genre would not have a decent turntable, and my brother is no exception. “ What do you got for vinyl? “ I asked. He responded by removing a cover, exposing a classic Technics 1200 turntable. My eyes lit up and I started to say “ Is that the one… “ and was interrupted with “ That’s THE one! “. You see, in our teen years he had picked up the legendary Technics 1200 and it has been serving him well ever since. I have quite a few fond memories with that baby. I knew I we were in for a treat, and so did he! With a wide range of albums to sample, ranging from Queen, Boney M, New Order, and Björk us brothers, with beers in hand, sat back and absorbed the the classic vinyl sound!

    The settings used was 3D+ enabled as the monitors were already angled, and XBass was disabled because the they have no problem reaching the lower registers. I figured that SET and Push/Pull to be too smoothing for vinyl (eventual testing proved my suspicions correct), so only the Classic Tube+ setting would be used. Normally, I find vinyl to sound rather flat, and lacking dynamics when compared to modern digital music, but the inclusion of the micro iTube2 injected all that I find lacking with the format! The sound came to life with a greater sense of expanded air and space, as well as greater focus of individual instruments and effects. Dynamics were enhanced and brought a much greater level of excitement; Bass possessed a nicely weighted bloom, the midrange texture gained a smooth and organic quality, and the treble became more crisp and well extended, with a much greater sense of natural air! Both my brothers couldn’t get over how much of an enhancement the micro iTube2 brought to vinyl, and to be honest neither could I! It was pure magic!

    AKG C314 Mic—> micro iTube2—> M-Audio Project Mix I/O—> M-Audio M3-8 powered monitors

    There was one last piece of audio tech that was staring me in the face, begging to be paired up with the micro iTube2; An AKG C314 microphone! “ Hey, can we try out that bad boy? “ I asked pointing to the mic. “ For sure! “ my brother replied “ There are actually microphones that have built in tube buffers. This should be good! “ and it was. 3D and XBass disabled, starting off with SET brought a wonderful enhancement to the already stellar sound. All 3 of us were adding in various Tom Foolery and no matter which voice, the resulting sound was smooth, detailed, well textured and possessed a classic richness to the tonality! Switching to the Classic Tube + and Push/Pull resulted in a more airy and crisp sound while simultaneously enhancing the natural texture and focus of both the lower-mid and midrange frequencies! Eventually, our voices were sampled and added into various tracks my brother was working on. It would have been pretty cool to include some of the audio we sampled, but on further thought the content wasn’t too crass to be review friendly. All in all, we had too much fun with the the micro iTube2! It was very rewarding to hang with my brothers, but to do so over fine spirits and great sounding music was priceless!

    Value

    At $375 USD, unparalleled, the micro iTube2 is a tube output stage, active tube preamp, tube buffer, as well as an impedance-matching device all in one package. If I were judging on versatility alone, the the micro iTube 2 would be more than fairly priced. The inclusion of the super sleek and sexy aircraft-grade CNC-aluminium anodized shell, top quality reference class components, and the 15V iPower make the micro iTube2 one heck of a deal! Sprinkle on some tube magic of iFi Audio’s class-A engineering and the micro iTube2 is a must have for any audiophile and enthusiast; There literally is nothing quite like it!

    Conclusion

    In closing, I can not help but think of the line from The Million Dollar Man: “ We can rebuild him. We have the technology. We can make him better than him was. Better, stronger, faster. “. Once hailed as the “Swiss army knife” of pre-amps, the micro iTube2 is not simply an upgraded model to the original, rather a complete redesign built upon trickle-down flagship topology. If I had to choose a word to best describe the overall qualities of the micro iTube2, it would be magic: The power of apparently influencing events by using mysterious forces, a quality of being beautiful and delightful in a way that seems remote from daily life, exceptional skill or talent! Bringing the analogue back to the music in today’s digital world is no small feat, yet with the micro iTube2 iFi defies what was once though impossible and delivers a 100% class-A SET tube buffer and pre-amp that not only magically re-introduces the forgotten natural harmonics but does so organically with absolutely zero negative effects! I don’t think I have ever encountered a device that has been as impactful on my music than the micro iTube2! It’s not often I label a product as a “must have!” (in fact, never), but given it’s price, outstanding features (that are border line magic!), flawless performance, and extreme versatility, if one is serious about their music the micro iTube2 is a must have and should be your next upgrade! Period!
    motberg, Wilashort, phthora and 6 others like this.
  2. jinxy245
    4.0/5,
    "Lush and Lovely"
    Pros - Works as advertised
    adds smoothness without sacrificing clarity
    usable filters
    can be used for speakers and headphones
    Cons - niche market
    runs hot (to be expected but potential negative)
    value needs to be weighed individually
    MicroiTubePic03.jpg

    Anyone that has been around this hobby for a while knows that there are many different things that influence the quality of sound we get from our gear. Countless articles are written about different amps, dacs, ear tips, ear pads, cables, etc. and the added nuances they can bring to the listening experience. All of these items have a primary function, ear comfort, isolation, signal transmission, signal conversion etc., with changing the sound supposedly being a secondary benefit. The ifi iTube2 is the only piece of equipment other than an equalizer that I can think of whose primary function is to alter sound,. It’s an interesting component that I likely would never have had the opportunity to hear; so my thanks go to Lawrence and ifi for organizing a tour for the Micro iTube2. For those who are unfamiliar with review tours, I receive no compensation other than my time with the review unit in exchange for my honest opinion to be posted here.(please forgive the images, which were all borrowed from the internet)

    So what is the Micro iTube2? To paraphrase the ifi website,

    “The micro iTube2 is a tubed output stage, tube preamp, tube buffer AND an impedance-matching device all in one. There is nothing like it. You can put the micro iTube2 before a solid-state preamp and another one after it, creating the effect of tubing the whole audio chain. Or you can choose to simply use the micro iTube2 as a very high-quality preamp by itself.”

    So it seems the iTube2 is created to impact the sound by adding a tube filter into the signal path. Whereas an equalizer targets a specific bandwidth, the iTube2 is geared more towards the overall tone, although it does have some equalizing properties. At first I was quite intrigued with the idea of adding the ‘tube sound’ to my setup. Then I had some doubts…it seemed a lot of trouble to go through for a ‘tonal shift’ if you will, and I wasn’t exactly sure how to integrate the iTube2 into my setup, so I originally decided to back out of the tour (more on that later). Finally, curiosity won out, and I asked to be included once again, and I can honestly say I am glad I did.

    This is, to my knowledge, a unique product. I have heard of tube buffers and the like in guitar set ups for performance or recording, but not in the audio community. The iTube2 can be configured either as a preamp or as a filter between just about any source and an amplifier. I wasn’t able to run the iTube2 as a preamp in my 2 channel home setup, which was one of my hesitations in participating. Since it can be inserted into a headphone audio chain, that’s where I concentrated my listening, with pleasing results. Obviously that’s where my review will concentrate, and I’ll do my best to touch on some of the relevant features, as well as give my impressions of how much the iTube2 impacted my listening experience.

    Anyone familiar with the ifi line of products will recognize the shape & layout of the iTube2. On the front from left to right there is the 3D Holographic+® matrix control used for Speakers (off, default & 30˚+), the Xbass+ control (OFF, 20 Hz [+6dB] and 20 Hz [+12dB]), the Tube+® circuit which selects the ‘sonic flavor’ you want ( Push-Pull tube power amplifier, classic tube amplifier, and Single-Ended Triode [SET] power amplifier) and a volume knob which presumably is only functional when set in preamplifier mode since it had no impact during my use as a buffer.
    front-iTube2.jpg

    On the rear you’ll find the input/output RCA jacks to connect the iTube2 to your source and amplifier, one side has the power input for attaching the charger, and on the bottom are the ‘dip switches’ for configuring the unit’s output as a preamp or a buffer, and the various adjustments to those settings. As confusing as those switches seem to be, there are only 4 settings listed; 0db & +9db as a buffer, and 0db & +9db as a preamp. There is a handy diagram for setting them printed on the bottom of unit for quick reference.
    iTube_Tech_Specs.png
    ifi Dip switches.png

    In keeping with my experience with all ifi products, the iTube2 is built solidly, although it is lighter than I might have expected. The knobs and switches feel solid, and the traditional ifi silver finish is quite attractive IMO. The accessories are fairly sparse, with a charger, ifi’s trademark purple RCA jacks (a unique cord color I haven’t seen anywhere else), a mini screwdriver (presumably for changing the tube), and I believe a right angle plug, which wasn’t in the box I received, so I won’t comment on it (things do get lost in transit on these tours). Sparse in this case is not a negative, because all the essentials are covered and there’s not much more I’d expect to find. I imagine there are no stacking bands because the Itube2 does run a bit hot (common for tubes) and benefits from having good ventilation. (ifi does sell a stacking rack made for their products, info here: http://ifi-audio.com/portfolio-view/accessory-irack/ )

    My major hesitation in participating in the ifi tour is that all the dacs I own are integrated (Hugo V1 & Dragonfly V1.2), so the iTube2 would have to be utilized between them and another amp. I thought that it might be interesting to try to run an RCA to 3.5mm cable from the ifi’s outs directly to some headphones, but I was informed that the iTube2 is NOT intended to be used as a headphone amp. One of the benefits listed for the iTube2 is as an impedance matcher, so as far as I can tell that benefit is only to the input of whatever amp you’re using. Regardless, I settled on using my Hugo to the iTube2 to my ALO Continental after my source (either directly from my computer via USB, or from my Shanling M2 by coaxial). The headphones I used were my ZMF Eikon and Sennheiser HD600.

    I have to say that once I stopped trying to figure out the best hook up and let myself simply listen, I began to really enjoy my time with the iTube2. Keep in mind that there seemed to be no way to feasibly test my setup with & without the iTube2, so my impressions are in no way scientific. My conclusions could be conformation bias, but I honestly don’t think so. The difference was audible to me, and I stand by what I heard.

    Although it seems these settings were engineered for use with speakers, they worked fairly well with headphones as well. The Xbass I found to be very well implemented. At 12db the bass was really thunderous yet I was surprised to find it wasn’t overly distorted with my ZMF Eikon. When set at 6db there was still a very effective boost, and even though I did most of my listening set to ‘off’, I found myself indulging in a bit of basshead pleasure from time to time, with both the HD600 and the Eikon. The 3D+ had a more subtle effect with headphones. I found any change to be concentrating on the treble, adding some clarity and ‘air’ with certain recordings (not very noticeable on others) which I found to be particularly pleasing with my Eikon. I don’t recall ever thinking it was too much.

    Of the different tube modes, my favorite was the classic tube amplifier. That setting had the best clarity IMO and it sounded the most dynamic. The highs were a touch clearer, the bass vivid and the mids equally present. Both the Push-Pull tube and Single-Ended Triode [SET] softened the sound a bit too much for my tastes, of course YMMV. I imagine each setting could change depending on the audio chain. Describing sound in words is difficult at best, but what I did find overall was a smoothness, perhaps a refining of the edges of the notes. What I didn’t find was a lack of clarity or a decrease in resolution. Everything still sounded ‘there’; I couldn’t pinpoint anything missing. What was ‘there’ didn’t change in tone, or go so far a smearing, but did seem to soften a touch. It was an addictive sound to be sure, and I found myself getting lost in longer listening sessions than I usually would.

    I genuinely enjoyed my time with the Micro iTube2. With a MSRP of $375, it is not for everyone. I’ve heard things like un-digitize, analog-ize and other such phrases that seem a bit over the top to me. I did experience a subtle warmness infused into my music, which once I heard, l wanted to hear more. Value is certainly in the pocket of the beholder, but I can think of worse ways to spend my cash. The iTube2 does seem to live up to it’s promise of adding the often sought after tube flavor to almost any set up.
  3. knorris908
    5.0/5,
    "Solid State Simplicity Yielding Warm Tubey Velvet"
    Pros - Simple setup, Easy A/B comparison of unaltered signal vs "tubified" sound. Ability to customize audio parameters to suit your current headphones from most any source, rather than constantly swapping headphones during your listening sessions.
    Cons - While still quite portable, not battery powered like the iDSD & iDSD Black Micros for TRUE portability during travel.
    iFi Micro iTube 2 Review


    Problem: I love music. I mean, REALLY love music. There is almost no iteration, form, or flavor that I can’t take joy in listening to given the right mood and environs...

    Secondly, I like like SIMPLE. Call me a victim of the “instant gratification age”, but I would rather plug in my headphones/speakers, select a song, and just be swept away by great sounding music, than spend time picking and choosing different parts, components, and mixing combinations is search of the elver-illusive “perfect sound” that I often see others pursue. Doesn’t mean that I don’t respect those who dedicate themselves to it, (And to some, I might seem that way myself! “Why would you ever need more than an iPhone and the stock Apple ear-buds to hear music Ken?”) but I would rather spend my fleeting spare time LISTENING than constantly chasing an aural ideal.


    Solution: For me, it’s solid state. I enjoy quality components and have tried many, but I almost always come back to solid state. No warm-up, more durable, (Resistant to shock/drops) and lastly, they are typically much smaller than analogue components.



    So that brings me to the subject at hand. I have a number of solid state amps that I use, and I have found my favorite headphone combinations for each. One of my primary criteria after fullness is detail. I love to hear separation and emphasis from each voice or instrument. But some combinations can take it a little too far, and that same lovely detail becomes sibilance, or harshness to the sound. By default, I would simply switch to “warmer-sounding headphones”, but this was usually at the cost of the very detail I valued. Also, what if I only have one set of headphones with me at the time? What then?


    Enter the iFi iTube, and now, iTube 2.


    I can truly say that I no longer have to rotate headphones with certain songs! When the iTube 2 is paired with a less than stellar DAC, there is marked improvement to the smoothness, and when it is paired with a great one, it still improved audio quality, but to a much less noticeable degree. Point being that it never made things worse by being added to the audio chain.


    So what is it?


    The iTube 2 has been out for a while so I won’t go into detail with specs, as they are all out there already. In short, the iTube 2 is an amalgam of a number of advances in audio technology:

    l Start with clean power! - There is an iPower power supply that provides battery-like quietness while still giving AC power benefits.

    l Tube+ circuit - The iTube 2 has a direct tube buffer with selectable sound signatures, (SET, Push-Pull, Classic) and a hi-end preamplifier that banishes digital harshness in favor of a glorious warm and full feel to your music.

    l 3D Holographic + - Ever have that “claustrophobic feel” to your sound that makes you wish your music sounded “bigger and fuller”? This is what you want!

    l XBASS+ - Xbass gives you a more emphasized low-end without introducing bloat or looseness , and without automatically crushing your mids.



    So is it difficult to use?


    NO! Remember when I said that I value simplicity in my audio equipment? Well, this is it. No need to “Tube-roll” by plugging fragile tubes with equally-fragile pins into a base that might not line up properly if you’re not careful and bend those same-said pins. With a simple flip of a switch, you can select “SET” (Single Ended Triode) mode, Push-Pull mode, or “Classic” mode. I tend to favor “SET” with 3D Holographic with my headphones that have smaller soundstage, and without 3D when connected to our 7.1 surround sound home theater.


    Connections? Super-easy! 1 A/C adapter plug on the side. (Round plug so you can’t plug it in “wrong-ways around”.) 4 RCA connectors on the back. (2 “INPUT” L/R and 2 “OUTPUT” L/R) Plug them in with standard stereo RCA patch cables. NOTE: iFi has consistently provided RCA patch cables with their Micro line of products. Know that these are not poorly-performing “cheap cables”. I have compared the performance between the stock purple iFi-provided cables against Belkin, Cables To Go, and Monoprice, shielded “gold-plated” cables, and found the iFi cables to perform just as well!

    Plug your source, (PC, Mp3 player, Phone, DAP, Turntable or DAC) to the INPUT connectors, then plug your amplifier (If using one) or speakers to the OUTPUT connectors. DONE!



    How does it sound?


    Well, From most impressive, down:

    l Lenovo Yoga Android Tablet - (Android 6) Straight, or through DAC, THE most improvement in how smooth, musical, and warm all my music sounded. There is an edge to the audio that I don’t hear from my other devices that makes music sound sharper, but also harsher than any other source I own. Without the DAC, I also hear more audio artifacts, but the iTube 2 helps to minimize their intrusiveness.

    l Apple iPhones (4S, 5, 6, & 7Plus) - Straight, or through DAC, the 2nd most improvement in how smooth, musical, and warm my music sounded. Did magic with old, 128-bit encoded MP3s and nicely enhanced iTunes AAC music.

    l PC USB --> iDSD DAC - Largely improved the harshness of my most sibilant music files without making them sound “muddy”, or lacking in detail.

    l DAP - Straight through my iBASSO DX90 shows the least improvement in how smooth, musical, and warm all my music sounded of all my portable sources. (It’s just THAT good!) With my iDSD Micro acting as DAC, it tends to smooth out any harshness a little more, but that is simply because it is a slightly more analytically-tuned (Precise) DAC than the one in my iBASSO.

    l Sony STR-DN1070 - This took forever! There are so many combinations to choose from. Sony as Analogue: Source, Source & Amplifier, Just Amplifier VS Sony as Digital: Source, Source & DAC, Amplifier, USB, WiFi, & Bluetooth. The Sony pretty-well held it’s ground no matter how it was connected. The main changes were in the selection of DSP options that Sony offers. Some smeared the detail completely, while others (bit-perfect) just laid-bare what was in the audio file. In the case of the former, the effects of the iTube 2 was barely detectable. With the latter, the iTube 2 provided similar performance to what I heard with the iPhones when playing well-encoded tracks, and performed more like it did with the Lenovo Yoga tablet with poorly/low encoded music tracks.



    Should I buy one?


    As always, this is a very personal value that you must weigh for yourself. To me, if you value:

    l Simplicity - Easy to use, “Set it and forget it” with no cumbersome menus to hunt around).

    l Small footprint - Can sit easily on your desk at home or work, or your nightstand at home or in a hotel while traveling.

    l Great buttery-smooth “Tube sound” that you can adjust without swapping parts.

    l Solid construction that can weather regular travel in a laptop bag, suitcase, or carry-on with minimal risk of arriving at your destination DOA.


    Then I’d answer with a resounding, “Yes”!
  4. ngoshawk
    5.0/5,
    "Tubey gooeyness is as good as tubey goodness!"
    Pros - Easy to hook up and use, adds a "velvety" sound to your music, multiple choices with which to customize your listening, affordable, multi-use (system) options
    Cons - Gets quite hot, but it is a tube-amp, afterall. None.
    iFi iTube2:

    [​IMG]

    Two wonderful things happened to me on one fine day recently: I found out that I would be first on the iFi Appreciation Tour, and we as a collective had decided the iTube2 would be the representative; AND I perused the iFi iDSD Micro Black Label thread, finding out that I was the lucky one drawn to receive the Unique Melody Martians…Hooolllyyyyy BUCKETS!!! Needless to say, it was a banner day in my humble abode. I was humbled and jumping like a kid given their allowance in front of a candy store. WOW! I am extremely thankful to @Lawrance for his help in this wonderful tour, as well as the logistics of arranging all. Plus, he was very quick to respond when my “doltishness” could not figure out how to hook the iTube2 up. Wonderful, he was, with the help.

    [​IMG]

    In the week between arrival and testing, I scoured the threads of Head-Fi regarding the original iTube as well as the early reviews. It really was a fascinating read regarding the history of the tubes used, and why they were chosen. Call me a fanboy, but I am a hooked-for-life in the philosophy of iFi. The link provided only gives a hint of the history behind the tubes. Lawrance goes into wonderful detail on the Head-Fi thread itself.

    [​IMG]

    [​IMG]
    [​IMG]


    A little background history…



    iFi iTube (original):



    http://ifi-audio.com/portfolio-view/micro-itube/



    And the link to Lawrance’s excellent tube history lesson, in 3 parts:



    https://www.head-fi.org/f/threads/ifi-audio-micro-itube2-buffer.828965/



    The basis of the tubes used is their historical use in WW2. They were sturdy, efficient, and lasted a good long time. Put away through historical efforts, iFi brought these wonderful tubes back out for our pleasure. And boy oh boy, did it work. I will trust all of you dear readers, to read all three parts of the history, they are good reads. Plus, I don’t want to spoil all of your fun!

    I have a small inexpensive tube amp, which uses the tubes in the pre-amp phase of the sound, I use on occasion, but this is the furthest up the tube-food-chain I have wandered, personally. Yes, I have heard multi-thousand dollar McIntosh systems (and would love to own a system of such accord someday); but this is the first time I have had such a lengthy audition.

    Upon proper connection, to the iFi iDSD Micro Black Label (henceforth known as BL, because iFi iDSD Micro Black Label takes a bloody long time to write…) and my MacBook Pro, I plugged in my new UM Martian’s. I will say, that it did take a bit for me to dial in the sound to my tastes, but when you realize all of the tuning options on both units, you will understand. I did first run the units flat, without the aid of 3D, or bass boost, so I could have a baseline sound with which to judge. And it was impressive. The iTube2 gave a lusher, more rich sound to the system, immediately. I understand that I was the first on the tour, but the package came open, and I assume somewhat broken in. It will be interesting to see what the followers of me find, with more tube burn in time, if any change is to occur. I was impressed, because I do value sound on the warm side.

    [​IMG]

    Withholding judgment, I continued to play with the options. I carefully would manipulate the “toggles” on the backside, for whatever “filter” I chose. What a cool idea this is, and it paid dividends in my listening enjoyment. The most used filter was the “Pre amp” filter set at 0dB. I determined, that with the bass boost and 3D switches, I did not need additional input from the iTube2. I did try it, and I could tell a difference volume-wise; but my old ears would be hard pressed to tell a difference sonically between the 9dB push and the others I used, SONICALLY. Hence, I chose the easier path of switching toggles (on the front). It was easy. Initially, the unit came set at “Buffer” 0dB. I changed to the Pre amp after a brief listen, and kept it that way.

    [​IMG]

    Some general comments from the dedicated thread:



    X-Bass is an active circuit, which can't operate without an active element. The iTube 2 substantially improves the SNR and THD over the older model:


    1. SNR - 119dB(A) @ 2V for iTube 2 vs. 111dB(A) @ 2V for original iTube
    2. THD - 0.009% @ 2V/600Ohm for iTube 2 vs. 0.05% @ 2V/600Ohm for original iTube

    In buffer mode and "Tube" setting (no gain, no volume control) you get X-Bass and vanishing low distortion and noise.
    This circuit is actually about 90% of a single-ended version of the iCAN Pro preamp output.
    And no, it is not designed to drive headphones, though it can drive 300 and 600 ohm loads to high levels.






    Sprinkle the ‘magic of SET’ into any system


    Features/Technologies


    1. High-end Direct Tube Buffer/High-End Direct Pre-amplifier
    2. Selectable tube sound signature (SET / Push-Pull / Classic)
    3. All-new 3D Holographic+® for Loudspeakers matrix system
    4. All-new XBass+® for Loudspeakers matrix system
    5. Pure analogue volume control
    6. Ultra-low Total Harmonic Distortion (THD): <0.009% (Tube+ off)
    7. 0dB or 9dB selectable gain
    8. Reference class parts quality from ELNA Silmic to C0G capacitors
    9. iPower (15V) included, ‘quieter than battery’ power supply
    10. Tube: NOS GE 5670×1

    [​IMG]


    Technical pdf:


    http://ifi-audio.com/wp-content/uploads/data/iTUBE2 - Tech Note One Why GE 5670.pdf


    Full information, iTube2:

    http://ifi-audio.com/portfolio-view/micro-itube2/


    Delving into the feature details:


    An interesting note is that while the toggle system carries over from other iFi products in this category; the three on the front (3D, bass boost, SET) have three settings each, something my BL does not (only two). So not only can you fine tune and add boost/3D/SET, you can, change all three to add two levels of “additional tuning.” I find this aspect eminently changeable and worth it. I found myself changing bass boost and 3D according to the music and song with which I listened. A nice feature.

    In working out the differences of the SET feature, I found that did indeed favor one, but that will have to wait. In a brief explanation, the three settings

    Up

    – a Single-Ended Triode power amplifier;

    Neutral

    – a Push-Pull tube power amplifier;

    Down

    – a classic tube amplifier.

    did indeed provide three distinct sounds, such that even these tired ears could fathom the difference and distinct betweenst them. As one review posted, the Push-Pull sounded like an acoustically well-set-up concert hall. To me, the Single-Ended Triode while giving a bit wider sound stage was not as communicative a sound as the Push-Pull. I did favor the Push-Pull and ran this setting for probably 85% of the time. I can concur and state that there was a nice wide concert-hall/acoustically near-perfect church-like sound to it. One in which I very much enjoyed, no matter what headphone I used.

    The 3D toggles provide three setting too: “opt out,” slight offset, and 30 degree offset. Opt out is just that, no 3D setting. The slight offset is similar to the BL offset, giving a wider sound stage as well as a bit more depth and height. Yes, I would call it a 3D sound…The 30 degree offset gives a VERY different sound. One in which the user feels as if the instruments are quite literally switching around, like an old Doors song, almost psychedelically. Maybe not quite that extreme, but I did find, on the majority of listenings that it gave me TOO much three-dimension definition. I felt it colored the outer aspect of the sound too much for my liking. I noticed this even when isolated without the BL settings turned on. With the 3D BL setting turned on, it made the situation worse. I was not as happy with that setting as I thought I would be, so I left the 3D (when turned on) to the middle setting, on the iTube2. I would play with the 3D on the BL, but found it best to leave only the iTube2 3D switch to the middle position.

    [​IMG]


    McIntosh sound for the home portable



    Once I figured out how to hook the critter up (thanks Lawrance!), the iTube 2 (iT2) started humming away hooked to its brethren, the iFi iDSD Micro Black Label (BL). And, it was magnificent through whatever I hooked into the headphone output of the BL…Grado GH-2, Unique Melody Martian, Vibro Labs Aria, Meze 99 Classic, Auqioquest Nightowl, it did not matter…all were made to feel more like a 50’s McIntosh sound, which to me is a beautiful sound to behold…

    [​IMG]
    Ummmm.....some initial issues....

    Whatever was hooked simply sung with that familiar warm enveloping tube sound. From the open airy sound of the wonderful GH-2, to the rich vibrant full, muscular sound of the Martian, the iT2 simply performs it’s magic warming all to an almost enhanced tubular sound. And I was glad.


    Comparison/Units used:

    MacBook Pro
    Shanling M1/M5
    FiiO x5iii/A5


    Grado GH-2
    Unique Melody Martian
    Vibro labs Aria
    Audioquest Nightowl
    Meze 99 Classic


    Songs auditioned:

    Ziggy Marley- I Am Human & Dragonfly (live and album version)

    twenty one pilots- Guns for Hands, Trees, Screen, Car Radio

    Bob Marley- No Woman No Cry, Buffalo Soldier, Three Little Birds

    Stevie Ray Vaughan- Look at Little Sister (live Austin City Limits), Mary Had A Little Lamb (same)



    The main listening set up was through my MacBook Pro, BL and the iTube2. I then switched between the excellent loaner Grado GH-2, and my UM Martian. To say I was thrilled, lucky, excited, and honored would be an understatement of grand proportions. I am a very lucky individual indeed, right now.



    Playing Ziggy’s I Am A Human, is just a fantastic synergy of not only culture, but of vibrant tube-loving warm-full sound. With a rich, textured bass that reaches down and plays a very strong foundation, to the support instruments in the mids and Ziggy’s voice taking front and center (but not boisterous) in a reverent tone, the song pretty much typifies what the iTube2 brings to the table, when working with the Grado GH-2. I am thoroughly impressed at the partnership, and do not want to let EITHER go anytime soon…Providing a solid support to the Grado’s forward mids, the iTube2 provided to added warmth with which the GH-2 benefits to fulfill a thoroughly enthralling sound. Sound stage of rich wide proportions, good depth and good height add to the excellent instrument separation heard. I am taken in by the tubular sound, and a throwback to a thoroughly modern version of that excellent 50’s sound through what could pass for a 50’s specific headphone, what with their architecture.



    SRV’s excellent live version of Look at Little Sister, replete with a flawless guitar change due to his impressive string break provides an excellent example of how diversity of sound comes through the iTube2. A simple look back at his roadie, and a flawless exchange ensues. Wonderful to watch, all the while reveling at Stevie Ray’s beautiful guitarmanship coupled with an incredibly versatile voice. His gruff voice can turn sweet melodic on a note; just as his bluesy guitar licks can turn from a luscious melodic, enthralling sound to the sharp staccato of a fast picked beat and almost tortuous (in the best possible way) sound. From one chord to the next, SRV was a master at playing, evident when he lowered by a chord his playing to accommodate the broken string. Versatile would be an insult to his musical nature. Throughout the sound, whether with the Grado, or UM Martian, the iTube2 added a sense of depth and warmth to this song that seemed to not be there otherwise. Instead of the proverbial front row setting, I was transformed into that guitar string. Moved to within his guitar, and seamlessly transferred to the replacement during his excellent vocal solo. I’m not sure what else the instrument of our listening can provide, but to thoroughly envelop us, taking us into our music and losing us in the sound. An incredible synergy ensued, as I replayed the song, over and over listening for that nuanced difference, and detail, which I may have missed.



    twenty one pilots Guns For Hands provided that incredible variation of slow to fast to slow and back to fast juxtaposition of sound, which can be a bear for some audio gear to handle. From the almost painful sound of Tyler’s excellent vocals, to the harsh drumming of Josh, I felt again as if I was inside the music, enveloped in that wonderful sound brought out by the twosome. From the upbeat sound and driving texture of the high parts through the listening combo, to the soft almost mournful parts, I was on edge the first time I listened, and rightly so. It was musical twisting at its best. A throwing of emotions through the iFi combo wrought with a rich texture to be savored. And I did. Layers of depth brought throw simple instruments of drums and piano, supported by the “off stage” instruments played with my emotions and listening. I was a very happy customer indeed. The iTube2, set on the middle SET, bass boost on, and 3D off, brought about this pleasurable listening. The BL brought the power, and both the Grado and Unique Melody’s were the final representation of this fantastic trio. One thoroughly to be enjoyed. This was probably the sound, which solidified my respect for the iTube2. When the instrument of our listening can give that much respect for our listening, then you have found something to treasure. I have said this almost exact statement before, but it is true…when that listening bliss comes through your instrument of listening, then you have reached that level where you can sit back and enjoy the sound. The music of your listening.



    Moving back to Ziggy, his two fantastic versions of Dragonfly provided me with the confirmation that I had indeed stumbled upon a gem. And a reasonably priced, to boot. The live version (used in other reviews, but listed here again, because it is so darn good…) is something to behold.





    The synergy between Ziggy and his supporting cast (especially the guitarist) is one of musical perfectness. My only wish is that the guitar solo, let alone the song would go on for another 10 minutes or so…Alas, I would have to replay it over and over, last night…


    And from that, I was able to discern a certain quality, which separated itself from my other listenings. One of acoustic depth. The perfectness of the two together, is only made more perfect by a subtle but noticeable mistakes within the song. REAL is how this could be described, making it all the more so, by their incredible work together. Without the iTube2 present, this was a bit bright for my treble-sensitive ears; but when you infuse the tubular nature into the equation, well it simply sings. Adding not only depth, but also musical texture (warm by virtue of the tubes…) and body that are not present when just running the BL. And I am thankful for the addition. Over and over I listened, making out those subtle nuances of sound, of texture, of airy-accoustic guitar coupled with the solid bass guitar background. The sound is beautiful, and I have to say, that I played this song the most, followed by Guns For Hand and Look at Little Sister. I really wish Ziggy would receive the recognition he deserves. And as such, he did just receive the George & Ira Gershwin Lifetime Achievement Award, which is thoroughly deserved.


    http://ziggymarley.com/


    Complimenting that is the studio version, and boy does it ever. From the opening native drumbeat to the acoustic guitar, and the support of the electric guitar, the song is superb through the iFi iTube2. Wrought with deep overtones of native beat, the tube sound adds to that rich display of sound. I feel as if we are in Jamaica as we listen. And I am happy. I play the song over and over, sometimes critically listening for the differences, sometime simply to listen. A deep sense of belonging is fashioned from this song, and it makes me quite honored to be included.


    A pattern has developed in my listening. One, which you could probably guess already. A sense of depth and rich texture pervade everything I play through the iTube2. As to how much depth and texture, well that depends upon the settings you desire. A full-on 12dB can be added through the bass boost, with a middle setting of 6dB (my preferred). If you desire a more open concert hall-like sound, then move the SET toggle to your desired spot, and enjoy.

    [​IMG]

    Additional hook ups:


    While perusing the offerings, I did hook the iTube2 up with my Shanling M1. Using the 3.5mm connector to the dual RCA connectors on the iTube2, then the BL, then headphones, I immediately noticed that the sound was not nearly as full and rich. While I could dial up the volume and settings, there was a definite lowering of quality…Not as rich, nor textured, nor detailed; I quickly reverted to the MacBook Pro set up. Order was restored. While I did not mind, and could adjust the settings to compensate (which is a benefit of such a system), the MacBook Pro was simply better. So I stayed with that. While a DAP would work (my FiiO x5iii was better than the M1), this really is made for desktop/laptop/home systems. As advertised, the iTube2 melds seamlessly with a home set up, and from the reviews I read, the 3D system benefits from that larger sound base. I do find that this system works well in the smaller situation, such as computers. So don’t rule this out for such situations. Versatile it is, adding that wonderfully velvet (almost an insult to use, probably better to use the professional term tubey-gooeyness) sound to pretty much everything I threw at it. Again, I do value a warm sound overall, but one that does not would be intelligent to give this critter a listen, too. If nothing else, for the way it enhances the sound, elevating it to a level above what it should. By that I mean the ability to make a recording sound simply sumptuous. What with this addition to the BL, the overall impression simply makes it for me, and I am glad.


    Finale:


    What with all of the tuning possibilities, from Buffer to Pre-amp, to the three each of 3D, Bass Boost and SET (tube settings); the number of possible listening scenarios is many. Throw in that you can fine-tune the Buffer/Pre-amp filters with 8 different dip-switches, and the possible iterations are quite numerous. One can surely find a sound, which they will find pleasing. In just a couple of hours I had the sound, which I enjoyed the most, tuning the unit until I was quite happy with the overall signature. Yes, it was on the warm side of neutral; but it was also the sound with which I liked the best. Even those who prefer a more cold analytical sound SHOULD be able to reach a listening level they will enjoy.

    [​IMG]

    I guess I am trying to say, that this little, and I consider it affordable, critter was easy to use (once Lawrance shoved me down the correct path!!), easy to change, easy to listen to, and easy to modify according to the needs of the song and signature desired. A “Jack-of-all-trades” would be an insult to this unit. The iTube2 is versatile, and worthy of an audition in not only your personal system but also computer and home system. It is quite good, and I was honored to be included on the appreciation tour. For that, I sincerely thank Lawrance, and @iFi for including me. This is a company, which gains my respect more and more with each passing opportunity to listen to their fine wares. Worth a listen, would be an understatement.

  5. ostewart
    5.0/5,
    "Tubey goodness just got better"
    Pros - Flexibility, sound quality, form factor.
    Firstly I would like to thank iFi for this sample to review, as always I try to write honest reviews, this unit has had over 50hrs of burn-in, no real differences were noted.
     
    Gear Used:
    HP Pavillion laptop > JDS Labs OL DAC > iTube2 > Marantz PM44 MKII SE > Denon SCM-50
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    Tech Specs:
    You can find a comprehensive list on the iFi Website:
    http://ifi-audio.com/portfolio-view/micro-itube2/
     
    Packaging, Accessories and Build Quality:
    The packaging is the same as the rest of the Micro line, which is fine by me. It comes in a long slim white box, on the front you get a picture of the product, on the L side of the box you get a true to size picture of the iTube2 side on, on the R side of the box it lists the key technologies used, and on the back you get the tech specs and additional information. One you remove the outer sleeve, and take the top off you are greeted by the iTube2 held in a little in tray. Underneath this you will find all the included accessories. They waste no space with the packaging, it is neat, looks good and I really like it.
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    Included accessories are good, you get a pair of short RCA interconnects, a small flat head screwdriver for changing the DIP switches on the bottom, rubber feet, power supply and an adaptor for it so the plug that goes in the iTube2 is at a right angle for neater installation, you also get a quick start guide which is very good and explains all the features without going too in depth.
     
    Build quality is the same as the rest of the micro range, it is a slim aluminium housed device, all precisely put together with excellent finish. The volume knob is also the power switch, it operates very smoothly, the front switches all feel like they will last, the inputs/outputs are sturdy the only delicate part is the DIP switch panel on the bottom, but they will last if switched carefully, and most people won’t change them much anyway.
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    Features:
    This little device is packed full of great little features, I won’t go in to too much detail but I will try and list them all.
     
    For the most part this is a valve buffer/pre-amp that adds a little tube magic in to the sound of your system. The amount can change whether you have it set to a 0dB buffer/pre-amp or a 9dB gain buffer/pre-amp, the latter being slightly warmer.
     
    It has one pair of RCA inputs, one pair of outputs, the LED on the top starts off red when you first turn it on, and turns orange in aprox a minute meaning it is ready to be used.
     
    Now for the front switches:
    Closest to the volume knob you have the option to choose between SET, - or Push-Pull. This one is all down to personal preference, you can have it sounding like a Single-Ended Triode power amp, classic low-distortion tube-based studio equipment or a Push-Pull tube power amplifier. With my system I preferred the – position, it sounded the most up front and engaging.
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    In the middle you have the Xbass switch, this is really good for smaller desktop speakers, iFi recommend the 6dB position for speakers missing only the lowes bass notes (40Hz and below), and the 12dB position for speakers missing some bass notes (80Hz and lower). Or you can leave it off if you have enough bass in your system. My little SCM-50 speakers benefited from the 12dB position.
     
    Last but not least you have the 3D Holographic with 30⁰+, - or +, iFi recommend the 30⁰+ for narrow placement of speakers, the – leaves this setting off, and the + recreates the original “width” of the soundstage and should be used as the default. I can say now this setting has completely changed my desktop listening experience, using the 30⁰+ due to my speakers being next to my PC monitor.
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    Sound:
    Well this greatly varies depending on your system and settings, but once I had messed about with the settings a little I have it set up to my preference and it has completely changed my desktop listening. This device also works well as a tube buffer for headphone systems, where you want a little tube magic, just stick it between your source and amp and happy listening.
     
    Now I have this set up as a 0dB buffer, with the XBass set at 12dB and the 3D Holographic at 30⁰+, it has helped my speakers not sound as thin, and also the soundstage is so much more accurate. The tubes adds that little bit of warmth, that makes them sound less harsh but still very detailed. The Xbass really helped fill out the low end without any added bloat, it is very precise and well controlled.

    The 3D holographic setting though is a game changer, if I turn it off it almost sounds as if I am listening to a mono recording, the soundstage got so much wider, and more natural. Pinpointing instruments is so easy now.
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    iFi Audio have taken the original iTube, which was and still is an awesome device, and managed to squeeze even more out of it without making it bigger, the great thing about this is that it fits in to any system and you can let it have very little influence over the sound, by having it as a pure 0dB buffer, and it will add a little tube sound. Or you can play with the settings and see what works best for your system.
    After playing about with the settings, it has made a big audible difference to my desktop setup which without this sounds a little thin, with very limited soundstage as it is not set up very well due to space and room constraints.
     
    Sound Perfection Rating: 10/10 (Such a great, featured packed device for all systems)