Review: iFi Audio iTube (tube magic for all systems)

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.

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.

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)