Head-Fi.org › Head Gear › Headphone Amplifiers › Desktop Amps › iFi Audio iTube

iFi Audio iTube

Posted

Pros: Rich and euphonic tube sound with selectable soundstage and Digital Antidote Plus enhancement.

Cons: Tailor mostly for speaker. Digital Antidote Plus' effectiveness depends on system.

iTube is the latest addition to iFi Audio ‘Micro’ line of audio gears. On one hand, it inhere the same minimalistic concept as the other Micro gears; on the other hand, it is a departure from the previous all-solid-state design. If anything, it is the first in Micro gears that will appeal more toward speaker user rather than headphone user. So what exactly does an iTube do? In essence, it is a tube buffer / pre-amp, with some extra features threw in.


iTu-01.jpg

Spec
Input voltage: AC 100-240v, 50/60Hz
Power consumption: under 4W Idle, 10W max
Input impedance: 1M ohm Direct Tube Buffer / 100k ohm Pre Amplifier with Volume Control
Output stage output impedance: less than 1 ohm
Corrected output impedance: Less than 200 ohm
Dimensions: 175(l) x 67 (w) x 28 (h) mm
Weight: 278g (0.61lbs)
MSRP: US$299

iTu-02.jpg

iTu-08.jpg

Gain - Buffer or Pre-amp
Like the newer iCAN, there is a user selectable gain switch on the belly of the housing. However, the switch also enable / disable the volume pot on the iTube, allowing it to run either as a Class A tube buffer or a pre-amp. In both modes, you can also choose either zero or +6dB gain, depends on how strong your source’s signal is. Of course, you will have to take into account whether the output will clip the input of the next device (which will be an amp or an amp section on an active speaker). My suggestion is, if your source has a 2V line level signal or something near it, keeps it at zero gain. If your source has a weak signal (i.e. older iPods only have only a 0.55V line-out), gives it the +6dB gain.

As for whether to use it as a pure buffer or pre-amp will depend on the gears you are connecting the iTube to. If it is feeding to a power amp that has no volume control of its own, then obviously you should use iTube in pre-amp mode to control the volume. If however the iTube is feeding into an active speaker that has its own volume control, then iTube should be configured as buffer. Note that the volume pot also doubles as the on/off switch, so you still need to turn it on even in the buffer mode, though volume will not be changed at all. As with all tube gears however, you should try to avoid rapid or frequent on/off action as much as possible in order to prolong the tube operational lifespan. If you are only going away for a short while, instead of turning it off, it might be better just to leave it on.

iTu-09.jpg

Sound Quality
Tube is always associated with noise and harmonic – in a way iTube is about those as well, but more on the harmonic and less on the noise. For measurement, I set the iTube up in a full iFi chain – staring with iUSB Power, which connected to the iDAC via the Gemini dual head USB cable. The line-out of the iDAC is fed into the iTube as a buffer, then to the iCAN with a 23.5 ohm dummy load. RMAA measurement is done with both the iTube in chain and without it for the comparison. Surprisingly, the impact of iTube, at least on graph, seems to be fairly minimum. Yes, it is noisier with the iTube, but we are talking about 0.001% of difference in THD and 0.004% in IMD+Noise, plus less than 2dBA in overall noise level. The numbers are small enough that I have to wonder how valid they will be in actual listening. As far as the frequency response goes, iTube is as flat as it can be, at least when the Digital Antidote Plus is not engaged (*but we will leave that discussion to the next section).

The actually listening experience with iTube however is a much less subtle business. Beside the setup mentioned above (plus a pair of Sony MDR-1R and a few IEM), most of my audition of the iTube is done in buffer mode with a pair of Creative GigaWorks T40 Series II 2.0 desktop speaker with an additional Creative sub-woofer. The first thing to pick up with the iTube, and particularly noticeable with headphones, is the distinctive ‘tube’ sound. So what is this tube sound? Well, it is a general richness that isn’t there before, like switching from a standard definition to a high definition signal on TV. It is the same image, but there is more information that fills up the space. At first, the effect is not that apparent. But once I switched back from iTube+iCAN to iCAN only, and just like going from HD to SD signal, everything sounds duller and harsher, even though I have been enjoying iCAN by itself for months now. I guess this is what iFi has referred as the ‘voodoo’ of the tube sound - the kind of euphonism that is just hard to get rid of once you are hooked. This is probably what makes tube gear user return to tube time and time again.

iTu-10.jpg

EQ
There are two additional features that are packed into the iTube – the 3D HolographicSound (3DHS) System and Digital Antidote Plus – well, calling the Digital Antidote Plus an EQ might not be the most accurate, but just bear with me here.

Don’t confuse the 3DHS on the iCAN to iTube. Yes, both have the same name and supposed to enhance soundstage, but that’s just about where the similarities end. The 3DHS on the iCAN is tuned with headphone in mind, but the one on iTube is all about speaker. The ‘small’ setting is meant for floor speakers or monitors that are already placed far apart and the goal is to put out a better perceived separation on the lower frequency region. The ‘wide’ setting however is meant for desktop monitor (such as PC speaker) and is aimed to project a bigger overall image than the speaker usually can. You can of course choose whichever setting that fits your own speaker configuration and taste, but I do find the wide setting does show significant improvement over my T40 S-II (which is a desktop speaker). In a way it does a similar function as the software based virtual surround sound effect built into the Windows OS, but much better in result. While Windows (and a good number of software movie players) tends to try to create a more hollowed out image between the left and right speakers to create the illusion of space, the 3DHS ‘Wide’ on iTube is more about pushing out an image larger than the speaker’s physical placement, as if they are actually further apart. This works out better for music listening as the mid-range still retains its texture and intensity as opposite to a hollowed out sound. As with the 3DHS on iCAN, I am quite amazed by iFi ability to fine tune the analog circuit and be better than software solution. But the one thing to note is that this 3DHS is for speaker only. Trying to use it with headphone will mostly mess up the image instead of improving it (same can probably be said on iCAN’s 3DHS negative effect on speaker).

SpectrumiTube.png

Digital Antidote Plus on the other hand is lesser of an EQ and more of a phase correction technique for digital source. The original idea of a ‘digital antidote’ comes from and patented by Anthony Taddeo of Taddeo Speakers in the early 90s to address the digititis of then popularized CD system. In simple terms, it involves splitting the analog signal from a digital source into two, delays one of them with a few milliseconds then recombines it back to the original signal in order to correct whatever phase error introduced in the digital stage and to recreate a ‘more analog like’ music reproduction. It had caused quite a stir in the audiophile’s community when it was first introduced, both positively and negatively, where some swear by it while other found the effect to be subtle at best. With the passing of Mr. Taddeo about 10 years ago and his company dissolved subsequently, the original Digital Antidote and the V2 hardware are no longer available. The Digital Antidote Plus (DAP) in the iTube is however a new take on the original concept and according to iFi, updated to be compatible to the latest and upcoming HD format of music.

So history asides, does the DAP work as advertised? Well, the first thing I did is to get some measurement off. RMAA is really not great on measuring beyond the basic stuff and certain not for phase - but one thing to look for is the treble roll-off that inheres from the original Digital Antidote circuit. As you can see from the graph, the area around 8kHz is actually bumped up by 0.4dB, then it drops off to -1dB around 15kHz before ending up at -2.5dB @ 20kHz. Given human is only sensitive to about 1dB of SPL change, the actual effect will be more noticeable above 15kHz. But since most human, especially adult, have likely lost a significant amount of hearing on the high treble region, the actual impact on listening should be relatively small. In real listening, my 30+ years-old ears really didn’t detect any major loss of treble from album to album. One thing I do pick up, and in a very obvious fashion, is the increase of texture and detail in the mid to bass range. This is most noticeable when I was listening to Piano Guys’ first and second album, where the decay and body of the piano and cello becoming unusually clear and their timbre becoming almost too good. To use the TV analogy again, it will be the equivalent of switching from HD to a 4K signal - Okay, perhaps this all seems to be too much of a hype. But it really isn’t about how SD to HD, or how HD to 4K that matters. It is about the increase of overall information from one to the other. With the iTube alone, it is like filling the background with all the missing notes. With the DAP engaged, it is like those notes are brought to the foreground. Is that how ‘analog sound’ should be, or is it a better approximation of live music that is somehow lost in the recording process in the digital era? I truly have no answer. But I can say I don’t dislike it. It is something that I can leave it on all the time and don’t feel like it has degraded the sound in any way. In fact, I think the result is really a plus to the overall music listening experience – regardless of whether it is an EQ, a phase correction or just another technological voodoo.

One last thing to note is that I can pick up the difference on DAP easier on the headphones than on the speaker. Then again, my headphones are generally better sounding and more revealing than my speaker. Your mileage however might differ.

iTu-04.jpg

…in Conclusion
I have a very small computer desk that also doubles as my working and listening area, and it is constantly full of all kind of gears and never enough in space. Early last week after receiving the iTube, I had the whole iFi chain setup on the desk for the iTube review and thought that I would have to disassemble them quickly in the next few days in order to reclaim the space back. The whole setup, as I am about to finish writing this review, is still sitting on the desk after almost 2 weeks. It could very well be staying there for a while longer, given how much music I have been enjoying recently over my Creative speaker - and to think that I am predominately an on-the-go IEM user. I guess this really sum up the iTube magic thingy. Sometime it is the seamlessly little stuffs that add up to make the whole experience worthwhile.

A thank to iFi Audio for the review sample

Posted

Pros: Add musicality and warm to your setup, The 3D HolographicSound® increase a lot the soundstage

Cons: Digital Antidote Plus' isn't much effective. Close RCA input and output connector

  I would like to thank Vincent at iFi for sending me this sample for review,

 

I’m a fan of IFI products. I have loved their dac and usb power supply (here is my review) so i have decided to

give a chance to the lastest product from the Micro line, the IFI iTube.

But first, who is IFI?

Ifi is a young English company with trickle-down technology licensed from AMR (AMR is a producer of Hi 

End valve components). Recently they released their new Nano line dedicated to portable listening which 

includes the battery supplied iDSD, a very interesting portable DSD dac, and the iCAN Nano, a portable 

headphone amplifier.

 

 

 

The iTube it’s a very unusual component, it’s a valve buffer stage that can be used also as a preamplifier 

which can be added to audio chain between the dac and the dedicated amplifier for our headphone. The 

goal is to remove from your setup the “digital and metallic” sound and reach the famous tube sound without 

losing the detail and dynamics that are typical of a digital system. 

Will the iTube sound good as the other IFI products?

 

Test setup

 

Source: PC with Jmedia River, Resonessence Labs Concero HD, Dragonquest Audiofly

Amplifier: Schiit Asgard, Questyle CMA800R

Headphone: Sennheiser HD650, Denon AH-D2000, Heir Audio A.4i, Hifiman HE500

 

Tech specs

 

Input voltage: AC 100-240v, 50/60Hz

Power consumption: <4W Idle, 10W max

Input impedance: 1M ohm Direct Tube Buffer

100k ohm Pre Amplifier with Volume Control

Output stage output impedance: <1 ohm

Corrected output impedance: <200 ohm

Dimensions: 175(l) x 67 (w) x 28 (h) mm

Weight: 278g (0.61lbs)

 

Packaging

 

The packing is the same of the other product from Micro line. Inside is the iTube, a power supply marked IFI 

and his extender, a couple of RCA cables, a small screwdriver that you will need to change the position of the 

little switch and four silicon feet.

 

Construction

 

The iTube shares the same good casework of the other products from IFI Micro Line. We have been really

impressed on how IFI it can put a valve in a such small case (175(l) x 67 (w) x 28 (h) mm).

The case is all made by aluminium with silver color and the assembly is good.

On the upper part there is the IFI logo printed, but instead of the dot on the “i" you find a small hole from 

where you can sees the light of the tube, a really nice thing. Another difference is the power supply hole on 

the side of the case. This is the only position allowed on the case, the two front panels are already full of 

connectors and switches.

 

Under the iTube there are 8 small switches that allow to choose between the four functions:

- Buffer stage with no gain (0 dB)

- Buffer with gain (6 dB)

- Preamplifier with no gain (0dB)

- Preamplifier with gain (6dB)

Next to the switches there is an illustration of their position to allow the various functionalities.

The gain function can be used in case of low output voltage source, but if the source has a standard 2 V exit 

it’s better to use the iTube with no gain.

On the iTube the input/output position is better than on the other Micro products, they are all on the same 

side. The four connector (2 pair of RCA) are very near but I didn’t have a problem with big connector like one 

of the Audience 24 s cables.

 

On the opposite side there are two curious switches and the volume knob. The knob it works also as an on/off 

switch and it doesn’t effect the volume if you use the iTube as a buffer.

The two switches turns on two patented circuit: 3D HolographicSound® and il Digital Antidote Plus®.

The first it can be set on three positions and it allows to increase the sound stage.

The second it can be set to two positions (on/off) and it can remove the digital signature and the digital

distortion.

The power supply is marked IFI and it’s a super low noise supply with a 9V and 2 A current.

After we have removed the two front panel it’s possible to take a look on the inside. The tube use by IFI is 

a NOS General Electric 5670 which is welded to the base. Don’t worry its life is evaluate in 100.000 

hours. The valve is parallel with the board. The board is divided by some white lines and every sector 

its marked with its function with a white writing. 

 

 

 

How does it sound

 

The best use of the iTube is as a tube buffer. The pre amp function has to be used only in case you don’t have 

a analogue volume on you amplifier so you can avoid using the PC’s digital volume. This review is focused on 

the buffer function.

The first time I had put it in my setup i didn’t know what to expect.

The first surprise was that iTube is noise-free and it lack the typical swish of tube components.

After i connected it up, I expected a strong frequency response change with a fatter bass and a lower detail 

and dynamics, but this didn’t happen. The iTube added only the best virtues of “tube sound” and the result 

is a more musical and warm sound, but the basic sonic signature of your setup it will remain the same.

The result is remarkable special with low end dacs that will lose their digital and metallic sound to enable 

them to perform much better. The iTube can also enable low quality files sound better. I have tried to 

connect the itube to the integrated sound card and the improvement was awesome. With high level dacs the 

improvement was less impressive, but it still makes their sound better anyway.

The 3DHolographicSound® is a really nice feature and it can increase the sound stage with a wider 

presentation. If you choose the lower level the sound stage it will be the same of your source, at level 1 the 

difference it will be a little difference but at the level 2 the soundstage it will much wider with the sound that 

seems to came from the outside of the headphones and with a lower congested sound . I have connected it 

also to my speaker and the effect was also better, especially with nearfield listening.

The effect of the Digital Antidote Plus® is less noticeable and it depends by the quality file and dac quality. 

In case of old style Upsampled or bad dacs, it removes the metallic sound but if you have a recent or a Nos 

dac you can turn it off. A good improvement can be noted if you use low quality file, like YouTube or Spotify 

recordings.

 

Conclusion

 

One again, IFI has impressed me.

This small buffer will add a fuller and warmer sound to your setup and also poor components made more 

enjoyable. With its preamp function it can be used instead of the digital sound of the PC with a better sound 

quality and with the gain function you can use low output voltage sources without any issues.

The 3D HolographicSound® will increase the sound stage and the Digital Antidote Plus® will remove the 

sense of digital from lower quality dacs or audio files, but it’s quite aimless with modern dac..

The build quality is good and the production engineering is fantastic, putting a tube in a such small case isnt’ 

that easy.

 

Summary

Score: 9 su 10

Pro:

- Good build and product engineering

- A loto f functions

- It adds the “tube sound” without any weaknesses

- Excellent 3D HolographicSound®

- The tube life is estimated at 100.000 hours

- The iTube will increase a lot the performance of the old dacs

Contro:

- The tube can’t be changed

- If you use with extremely big RCA connectors you may have spacing issues

 

Source: Stereo Head

Posted

Pros: Warm, smooth tubey sound in any system

Cons: none i can think of.

iFi iTube Review:

 

I would like to thank Vincent at iFi for sending me this sample for review, I will try to write an honest review, this unit received well over 100hrs of burn-in as it has a vacuum tube in it, which are notorious for needing long burn in times.

 

The iTube was tested with various headphones including the German Maestro GMP 8.35D + GMP 400 and also IEM's like the Westone UM Pro30 and Final Audio Design Piano Forte X-G.

 

I used the iTube in different configurations, mainly iPod Classic 160gb > Silver LOD > iTube > iCan > Headphones, but also Asus M50vm > Gemini USB > iDAC > iTube > iCan > Headphones

 

 

Tech Specs:

Power consumption: 7W

Input impedance: 1M ohm direct Tube buffer

                          100k ohm Tube pre amplifier with volume control.

Output stage impedance: < 1 ohm

Output impedance corrected: < 160 ohm

Weight: 233g

Dimensions: 175(l) x 67(w) x 28(h) mm

Warranty: 12 months

Price: £275

 

Packaging, Build Quality and Accessories:

Packaging is a simple white box, very elegant and simplistic, it has a picture of the iTube on the front, on one of the sides it has a list of the features, on the other side a picture of the side of the iTube, and on the back you will find all the technical information. This is just a sleeve, out of this slides a white box with iFi in silver pressed on the top of the box. Once you open this you are presented with the iTube in a card in tray, and underneath this you will find the accessories included. The packaging is a little Apple-esque but I do like the simplistic design.

 

Accessories included are just the necessary, 4 adhesive rubber feet, a RCA-RCA cable, power supply (ultra low noise, nice to see they don’t forget the small details) and a little flat head screw driver for changing the iTube's settings.

 

Build quality is good, the casing is aluminum, and feels great, I really like the finish, semi matte and it also doesn’t scratch easily which is great.  The switches on the front are high quality and actually quite stiff, the volume knob (acts as power switch too) is NOT an Alps pot, but one made specially for iFi with tighter tolerance than Alps pots, which means it is very high quality.

 

 

Features/Layout:

The iTube has the power input on the side as both RCA in and out are located on the back. The front has a volume knob for when it's used as a preamp, it is also the on/off switch, and the digital antidote plus and 3D (designed for speakers) switches. Also on the bottom are the pins for changing the gain and preamp settings (0db buffer,+ 6db buffer, 0db preamp, +6db preamp). The iTube has a hole in the top of the housing through which you can see the glow of the tube, but not big enough to see the tube itself.

 

The iTube is a valve buffer which can also be used as a preamp for speakers. Being a buffer it has great versatility as you can put it in any system and introduce a little of that tube magic many people talk about, iFi call it the "Swiss army knife of audio". It uses a General Electric NOS valve, which is soldered to an adapter on the circuit board, so this is not made for tube rolling unfortunately, but the stock tube is excellent. It also has a 3D sound setting which is more suited to speakers than headphones, unfortunately I have yet been able to test the effect of the 3D settings for speakers.

 

It also has something called Digital Antidote Plus, which is supposed to reduce "harshness" which is sometimes present in digital recording, I must admit I leave this feature switched on as it doesn't take any detail away from the music but does improve listening pleasure by removing the harshness as advertised, it is a subtle difference but contributes to a more pleasurable listen. As I said before it doesn't reduce the amount of highs or take away any of the detail, otherwise I wouldn't use it, its effect is more noticed on badly recorded tracks, which pretty much goes without saying.

 

 

Sound:

As stated above, most listening was done with the iTube hooked up to the iCan and the most used headphones were the German Maestro GMP 400.

 

I let the valve burn-in for over 100hrs before review, and let it warm up before critical listening. Well this is a very interesting device, I love the versatility, that you can use it in any system and it will add a little something to the sound without taking much away, this will never be the weakest link in a system, that's for sure. Talking to Vincent from iFi he was explaining that even putting this into a high end system can still improve it (tried and tested FYI).

 

As stated I have yet to set up my speaker system so cannot comment on the preamp stage but as a buffer in my system it is incredibly good. First I started off using it as a 0dB gain buffer, which didn't change the sound of the system much (mainly used with the iCan) but did add a tiny bit of warmth and smoothness to the sound without taking away the speed and dynamics of the music. It also didn't take away the detail in the highs, just gave the whole sound a smoother presentation.

 

Now after talking to Vincent he said that by changing the gain settings will give a more tubey sound or less tubey sound I decided to experiment, as that is what the settings are for. Now I put it on 6dB gain buffer and that added a bit more warmth and fullness to the sound. With the German Maestros this is a great improvement as previously stated they lack a tiny bit of body and fullness. With the Piano Forte X-G this was not as good as they became too thick sounding (preferred 0dB buffer). This doesn't take too much detail or presence from the highs and they are still sparkly and extended just not as in your face.

 

As I said this unit is very versatile, I know some audio purists will disagree with anything that might add distortion to the signal path, but this is my first tube device and I must say I do understand the attraction to them. They do offer a smoother, fuller bodied, more natural sound. For pure musical enjoyment I do prefer the added tube "magic" but for neutral/monitoring I understand why it might not be good.

 

Depending on the headphones you are using, you can change the settings to your preferred sound, that is what I like about this device, it is not for everyone, but for those that want a little bit of tube in their system without sacrificing the rest, the iTube is great, it is about personal preference and musical enjoyment (isn't that why we all got in to this?) not defining neutrality.

 

So there we have it, a versatile device that you can put in any system, that won't take away the essence of the system, just add a little musicality. I can see myself using this in a lot of future systems to come, speakers and headphones.

 

Sound Perfection Rating: 9/10 (for being so versatile and sounding so good)

 

 

Tracks Used:
Skrillex – First Of The Year (Equinox) (320kbps MP3)
Paramore – Franklin (320kbps MP3)
Diana Krall – The Girl In The Other Room (FLAC)
Deolinda – Passou Por Mim E Sorriu (live) (ALAC)
Suicide Silence – Unanswered (FLAC)
Massive Attack – Angel (ALAC)
Eat Static – Dzhopa Dream (ALAC)
The XX – Crystalised (FLAC)
Funeral For A Friend – Bend Your Arms To Look Like Wings (ALAC)
Mumford & Sons – Little Lion Man (FLAC)
The Scene Aesthetic – Humans (259kbps MP3)
A Hero A Fake – Swallowed By The Sea (254kbps MP3)
Vivaldi – The Four Seasons, Spring Allegro (ALAC)
Johnny Craig – Children Of Divorce (161kbps MP3)
Deadmau5 + Kaskade – I Remember (Caspa Remix) (320kbps MP3)
Black Uhuru – Utterance (ALAC)
We Are The In Crowd – Never Be What You Want (226kbps MP3)
Silverstein – Discovering The Waterfront (320kbps MP3)
Concept Of Thought – Our Thought (FLAC)
Nirvana – Something In The Way (Unplugged) (ALAC)

Posted

Pros: Adds smoothness to any reasonably priced system with a dedicated amp, Small, Soundstage control, dissipates heat well through the aluminium casing.

Cons: Aesthetics can clash with some neat setups. Not much else really.

 Here is the original review that I posted on my blog: http://noblehifi.blogspot.co.uk/2013/08/ifi-itube-review.html

 

EDD_7046.jpg

Disclaimer: A big thank you to Ifi for loaning me the iTube for this review!


After hearing the iCan I was eager to get my hands on more Ifi gear. Now I've even been lucky enough to get almost their entire catalog, as well as an exclusive. The iTube is launched today - 16th August (£275). This is a fascinating little audio gadget - a buffer stage with a pure analogue circuit that includes an active tube (GE5670). The iTube can be added to pretty much any audio chain with a dedicated amplifier (before the amplification stage), be it for headphones or speakers. Additional features include the option to boost sound by 6dB, it can be used as a pre-amp (with or without the 6dB boost), but it also has two other features to modify sound. One is called '3D Holographic' - a three position switch that alters soundstage for different systems, correcting for frequency definition and speaker placement. This was first seen on the iCAN, although that one was tuned for headphones and this one is tuned purely for speakers. To help me explain the second feature [the Digital Antidote] here's some info from Ifi:


"The original patented Digital Antidote circuit takes the analogue input signal and executes various timing and phase correction duties, all in the analogue domain. This drastically reduces phase error introduced by the digital source as well as increasing the amplitude resolution (by nearly one bit). Yes, there is a small roll-off effect but as one can see, it certainly is not a simple roll-off filter.

 

 

 

 

 

iTube_01.JPG

With the iTUBE’s Digital Antidote Plus®, this active tube [version  3.0] is ready for all digital formats right the way up to the latest high-resolution PCM/DXD/DSD and beyond. Now you can finally relax and enjoy your digital audio for longer."

The 'Digital Antidote' (which I will refer to as 'DA' from now on) can be turned on or off with a switch on the front of the unit. At first I thought that this switch might act as some kind of bypass for the entire system, removing the tube from the chain, but this is not the case (the tube is always being used). It's nice that you can add the DA effect on top of the tube buffer, this just meant there was no easy way for me to A/B the effect of the tube itself.


I admit to having no experience with tube amplifiers thus far (of which I'm quite ashamed), but I am very keen to hear some. The potential with the iTube is pretty clear, benefits of tube sound while keeping your solid state amplifier - an interesting prospect indeed. Here's a close-up shot of the glowing tube (this thing does get hot!), viewed through the dot of the 'i' in the company logo - nice design touch guys.

EDD_7027.jpg

     SOUND

I was expecting a tonality shift with the iTube added to the audio chain. I assumed there would be more warmth, stereo-typically associated with tube amplifiers, but no. I've heard of some tube amps defying this preconception, but perhaps this is more to do with the tube not being in the amplification. For those interested in the iTube who are still fond of their Solid State amplifier's tonality, you'll be happy to hear that there's little change in this regard. The caveat is that some instruments feel inherently different in their presentation. They sound better rendered, more full and perhaps this leads to them sounding a little "warmer", but I felt that there was no overall colouration. Certain aspects of the sound just seemed more real/natural. A nice smoothness is infused to the sound, which I noticed and enjoyed more the more I listened.


The changes that the iTube brings can feel subtle initially. This is not true of the 3D holographic sound however, which was very obvious and easy to A/B. Unfortunately A/B'ing the rest of the effects is impossible to do with ease due to a slow switching process of the iTube from the chain. Unless you have an identical system (source, amplifier and speakers or headphones) it's easy to forget the exact sound you were listening to. After getting used to the iTube being in the system however the music felt instantly more jarring (harsh and edgy) once the iTube was removed. Then all I wanted to do was put the iTube back in. 

The same thing happened to me when I first started listening to expensive systems. Going up I didn't notice much, but coming back down it really hit me. Like a computer upgrade you seem to adapt and accept improvements with little perceivable difference, whereas a downgrade is very different story. Over time it feels like my brain has picked up these differences in general, but when you're not used to something it can easily go unnoticed.


The DA effect is a tricky one to pin down. Although it should be easy to A/B because of the switch, I struggled to tell the difference between it being on or off. It's a more subtle effect than the tubes but perhaps I'm still in my early stages with this one. Ifi explained to me that it makes a bigger difference in lesser systems. I didn't spend a huge amount of time A/B'ing this effect unfortunate as I was mostly switching it between speakers and headphone systems. I usually had the switch on when it was being used so if that added to the effects it had on my system then I'm glad it's there. 

 

The 3D Holographic Sound in the iTube has been redesigned to cater for different speaker positions so is quite different from the version found in the iCAN. The effect in the iTube seems rather more subtle than the iCAN when used with headphones and I did enjoy it at times, but I'm told that it's not designed to work like this. 

For speakers this is a really nice feature to have considering that they are often fundamentally difficult to position and tune for the best soundstage. My speakers are a little cramped for my living room and they really benefited from the wide effect on some tracks. I also liked being able to change it for different music, so a big thumbs up from me here!

EDD_7041.jpg

     COMPARISONS

There are a few tube buffers around already, but it's certainly not a common consumer product at the moment. There's the Musical Fidelity X10 V3 (discontinued, but sold for around £250) and the Grant Fidelity B-283 (around £150). Searching for a 'tube buffer' on Google mostly brings up eBay listing from China. Unfortunately I can't say anything about how the iTube compares to any of these other models on sonic ability. What I can say is that the iTube seems smaller and neater than the consumer models mentioned above. Some of the eBay tat looked equally sized, but not exactly neat or pretty (exposed PCB's and bits sticking out).


I found an interesting paragraph on the Grant Fidelity website titled "who the B-283 is not for". It points out that if you've already spent a lot of money on your audio set up ($10k+) then you won't hear much of a difference by adding a tube buffer. Their reasoning is that you would have already paid good money to provide the same effects that the tube buffer provides. Having heard the £3500 Resonessence Invicta's wonderfully smooth sound I can say that this sounds like a very reasonable statement. That said, I feel the need to point out the iTube's additional features for controlling harshness and soundstage and what they could also bring to a system. 

 

 

EDD_7044.jpg

     BUILD

The construction of the iTube is pretty good. It's all solid metal on the outside, even the volume dial. It comes complete with rubber feet, power extension and two sets of RCA leads to get you started. The shape and style is also consistent with the rest of the Ifi range so if you would like to combine them they do stack nicely. I have almost the entire range of Ifi gear here at the moment and can say that not only do they stack nicely, but they sound great together too. The max combination you can utilise in one go consists of five devices!:

 

Computer > iUSB Gemini > iDAC > iTube > iCAN > Headphones - wow!


That's a pretty impressive collection of devices to make sound, but what a beautiful sounding system it is. Although visually it could do with some smaller and prettier RCA cables it's quite pretty too. 

 

EDD_7004.jpg

Also required to connect these monsters are: another USB cable, three power leads and two RCA cables. All of this is supplied of course, but it won't look quite as neat as this when it's working. My only real complaint about this setup is that you can't output all that to speakers at the same time as headphones. Before I get too deep into analyzing these units as a whole, let's get back to the iTube...


The power switch for the iTube is built into the metal volume dial. If you're not using the unit as a pre-amplifier as well then you can turn it anywhere to the right to turn it on. When you do you will see the green lights on the front come on and the tube will start glowing. I wish that the iCan had this same mechanism. The only way to turn that off is to yank the power cord out, which is less than ideal on a class-a amp that gets almost as hot as the iTube.


The iTube is a pretty simple and straight forward device, with no real down sides. If you turn on the iTube before the amplification you can get a loud popping noise, but this is true of pretty much any source to some extent and should always be avoided anyway. I made the mistake once, but never again. I can't even nit pick with the heat since that's simply the chassis doing a good job at heat dissipation. I'm really scratching my head to think of negatives at this point... no, there really isn't anything to speak of.

EDD_7033.jpg

Moving around the iTube is something you might do often if you switch it from a headphone to a speaker system, like I did. I did wish for dual outputs on the iTube so that it could be used for both system more easily, although that would force the chassis to be larger, since there's no room for another set of RCA outputs. I'm not sure that would have a desirable effect on the circuitry either, so the only option will be to have two of them.


     FINAL WORDS

I'm not quite sure what I expected from the iTube, because it did surprise me in a few ways. Initially I felt a little let down by it's subtlety, but ultimately I came to appreciate that subtlety rather a lot. I like that it doesn't change the tonality of your amplifier and the smoothness it adds to the sound is addictive - it does what it sets out to.


I expected to notice the effects and appreciate the iTube more with headphones, but so far it's the speaker system that has impressed me the most (with the 3D effects too). I'm not saying that it doesn't work with headphones, because I don't want to live without the iTube in either of my systems.

 

EDD_7049.jpg

 

 

     EQUIPMENT USED

Desktop PC, Media PC, Dell Vosto Laptop, Ifi iCan, Ifi Gemini, Ifi iDAC, Ifi iPower, Audiolab M-DAC, Audiolab 8200P, Denon AH-D7000, Hifiman HE-500, SoundMAGIC HP200, WeSC Chambers RZA Premium, Epiphany Acoustics Atratus, Schiit PYST, Arcam rBlink, Samsung Galaxy Note 2

No member lists contain this item yet.
iFi Audio iTube
By:
Description:

A specially‐developed active Class A tube buffer/pre‐amplifier with two active correction circuits dedicated for digital and analogue audio sources, including the 3D Holographic Sound® system and the Digital Antidote Plus® circuit, in order to bring the "magic of tubes" to any music playback system.

Details:
DetailValue
Models:
Model Name/TypeMPNEAN/UPC
Head-Fi.org › Head Gear › Headphone Amplifiers › Desktop Amps › iFi Audio iTube