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September 2013
iFi micro iTube 'Swiss Army Knife'
Hi-Fi's most funky box of tricks?
Review By Clive Meakins
ifi
don't need much in the way introduction now as they are well established as an
off-shoot of AMR. Some of their diminutive and very affordable products use
technology trickled down from their AMR big brother. This time the technology
inside the iTube is very much all iFi. The iTube uses the now familiar iFi
designed plug-top power supply and iFi extruded aluminum casework.
iFi position the iTUBE as a Swiss Army knife of
HiFi and it is so. It can be configured:
As a buffer with zero or 6dB gain
As a single input preamp with zero or 6dB gain with manual volume control
To tailor bass spatial location to the way our ears work
To ameliorate digital edge and harshness
It would be all too easy to dismiss the iTube as a gimmick; seriously, do not be tempted to do this. The iTube is a very well-conceived piece of kit. I must confess that when I was told what the iTUBE does I was a little skeptical about it; had it been April 1st would have been thinking I smell a rat. There is no rat; instead it's something every music buff should consider buying. Was asked to ensure I ran the iTube for a full week 24/7 and duly complied... and then some; I grabbed an occasional listen and can confirm the sound does improve with burn-in.
The iTube has a warm heart; the heart is a miniature NOS tube,
a GE 5670. This conservatively run tube endows the iTube with a pleasing warmth
to the touch. The dot on the iFi logo is a hole above the tube providing
ventilation and red glow confirming operation. Neat.
Looking at the underside of the extruded enclosure reveals a set of DIP switches for you to set some of the iTube modes. It comes with a tool for you to use to flick the switches, a set of interconnects and power lead adapter you may find useful should you not want the power lead firing a long way out of the side of the iTube. The functions you'll need in daily use are accessed via two switches on the front panel and there's also the volume control which only operates in preamp mode. Most of my listening was done with my system setup with the following:
Trans-Fi Salvation record deck, Transfiguration Spirit
cartridge, iFi iPhono
JPLAY into Metrum
Octave mkII DAC with iFi
iUSBPower
Bent
Audio AVC-1 preamp
LadyDay LD91 300B SE power amps
Two XTZ Sub Amp 1 DSP
Bastanis / Trans-Fi hybrid open baffles speakers
Buffer
Without Gain
As a buffer the iTube offers an extremely easy
1M ohm input impedance. In my time I've used the solid-state Burson Buffer and
the tube-based Musical Fidelity X10D. The X10D was far from transparent, it gave
warmth but added grunge. The Burson Buffer is way more transparent, seemingly
adding little sonic footprint.
My first aim was to check how well the iTube performed as a
buffer, was it transparent? I found that insertion loss due to introducing the
iTube into my system is frankly very hard to detect. I'm not confident I could
reliably tell you whether or not the iTube configured as buffer was in my system
or not, except perhaps with the very best recordings. The very best
recordings are just ever so slightly less open and airy with the buffer; the
difference though is incredibly small indeed. You might think this renders the
iTube buffer redundant; it does as a buffer in my system because I don't need a
buffer but a lot of people with passive preamps will benefit from using the
iTube as a buffer. The key point for me is that the buffer is as near
transparent as is possible so I'm comfortable that by using the 3D
HolographicSound and Digital Antidote Plus functions I'm not compromising my
system with a worryingly degrading buffer. Should you need a buffer to better
match your sources to a passive preamp and power amp then I foresee very
worthwhile sonic benefits simply by using the iTube as a buffer.
Buffer With
6dB Gain
Using the buffer with 6dB of gain configured
via the dip switches on the underside of the iTube I could detect no change in
the sound versus without gain. I reduced my AVC-1 preamp level by 6dB to make
this a fair test.
Preamp
Without Gain
Next up was running the iTube as a preamp
without gain; the sound was remarkably good. The main drop-off I noticed versus
my far more expensive AVC-1 preamp was that the bass was not as tight as I'm
used to. With lesser preamps I usually find soundstage width and depth are
compromised, not so here. The iTube couldn't quite match the bass tightness, the
overall openness and treble decay of the AVC-1 but the iTube put up one heck of
a fight and that's without taking price into account. The iTube is easily good
enough to be a serious alternative to many preamps, especially as it provided a
friendly 100 kOhm input impedance. The downside is that there's only one set of
inputs and outputs. Indeed the iTube was hampered in my comparison with the
AVC-1 by my needing to use dual RCA adapters with the iTube as I needed the
preamp to output to both my bass amps and main amps.
Preamp With
6dB Gain
When switching the preamp to give 6dB of gain I
set the level to match how I was listening with zero gain. I struggled to hear
much difference and if anything the sound quality improved ever so slightly in
terms of bass clarity.
3D
Holographic Sound
This function is intended to improve our
ability to detect the location of bass instruments, there are 3 settings:
Direct, Hi-Fi and Desktop. ifi went back to the work by Alan Dower Blumlein from
the 1930s at the very dawn of stereo. This is linked of the Binaural patent by
Blumlein. Essentially it's about our hearing bass frequencies differently that
those higher up the spectrum due to the dimensions of the human head.
Direct
– this simply operates as a buffer, switching out the 3D Holographic Sound.
Hi-Fi
– with this setting bass is supposed to be better located by the listener.
Using a modern recording with a bouncy bass, in this case Caro Emerald / Deleted
Scenes from the Cutting Room Floor, the drums became more distinct. There was
less of a simple thump and more of a bass sound with shape and texture, it
sounded more realistic. Moving onto Annie Lennox / Diva I found the bass guitar
notes to be cleaner, the best way I can put this is that the bass notes were
better described. I could not
locate bass any better but it was time now to move onto analogue recordings to
investigate further. With Sonny Rollins / Saxophone Colossus I could be sure
real (i.e. nothing synthesized) instruments were being played so this should be
a good test. Playing Moritat first of all I had to find a way to get myself to
ignore Sonny's sax, which was a challenge. In HiFi mode the double bass sounded
less thrumy, I could better hear the double bass strings vibrating; I could
better locate Doug Watkins on double bass. A side effect of this more detailed
and cleaner sound was that the double bass shrank back into the mix a tad. I
simply turned my bass amps a little to compensate and all was good. In more
typical systems it may be necessary to move the speakers a few inches closer to
the rear wall to re-balance the bass.
Desktop – used on my main system, the soundstage became a little wider and now left and right seem to bend around towards the listing position almost like a control bridge on ship or a major computer installation but this is not how this mode is intended to be used, nonetheless it was interesting. I tried the desktop mode with my desktop/holiday system which is a laptop running Foobar2000/ASIO4ALL into a USB DAC and Creative Labs active T40 speakers. The whole soundstage expanded, switching 3D Holographic Sound out of the system resulted in a shut-in sound. 3D Holographic Sound works really well, the improvement in Desktop mode was dramatic.
Digital
Antidote Plus
The purpose of this feature is to reduce
digital harshness. iFi acknowledge the work by Anthony Taddeo in the 1990s and
have built on this. There was a time when I could tell from outside a room
whether a CD or record was being played; the spit present on vocals was a dead
giveaway. Those of us with NOS DACs probably suffer least or quite possibly
bought NOS DACs because we are particularly sensitive to spit and spitch sounds.
iFi refer to the wider digital harshness issue "digititis". The Digital
Antidote Plus feature of the iTube curtails the ability to hear hardness on "s",
"t" and similar sounds. Whilst the Metrum Octave mkII DAC I was using is very
good in this respect there are recordings that are a still little too spitty for
my liking, so I chose some of these. I found switching in Digital Antidote Plus
was useful in providing a well judged compromise between fixing the problem and
not wrecking the "presence band" frequencies. This is a great facility to have
on hand, I found I used it more than I expected to.
Conclusions
It would be all too easy to dismiss this
diminutive box of tricks as just as a plaything. This would be a mistake.
1) The iTube operates as a very useful buffer, assisting sources with a less than ideal ability to drive tricky loads, quite likely via a passive preamp.
2) The iTube preamp capabilities are surprisingly good, as a
single input preamp it holds its own in my reference system in terms of sound
quality.
3) The iTube spatial effects due to 3D Holographic Sound are of long-lasting interest,
4) The iTube Digital Antidote Plus does a surprisingly useful
job in reducing "digititis".
You can place the iTube between pre and power amps, though in my case this wasn't viable long-term as I require two outputs from a preamp. For me it's not a question of whether I need an iFi Audio iTube; rather it's how many do I need? I could do with one iTube for my DAC, another for my phono stage and a third one for my desktop system.
Specifications
Type: Stereo analog preamplifier with audio 'enhancements'
Input Voltage: AC 100-240v, 50/60Hz
Input Impedance: 1M Ohm Direct Tube Buffer
100 kOhm preamplifier with volume control
Output Impedance: <1 Ohm
Corrected Output Impedance: <200 Ohm
Dimensions: 175 x 67 x 28 (LxWxH in mm)
Weight:278 grams (0.61 lbs)
Warranty: 12 months
Price: $299, €299 and £275 including European VAT
Company Information
ifi Audio
E-mail: contact@ifi-audio.com
Website: www.ifi-audio.com
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