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
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.
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.
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!
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.
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.
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.
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.
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.
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