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iFi-audio Micro Series – iTube/Pre-amplifier Review: Part I

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Setup and associated equipment

I believe the vast majority of people interested in iFi products will probably use them in a computer setup or with a moderately priced or inexpensive audio system; either desktop or traditional two channel audio. With this in mind, I decided to audition the various iFi components with my Virtue Audio M451 Sensation integrated amplifier, rather than my usually more expensive electronics. An OppO 981 DVD player normally used as a transport for reviews operated solely as a CD player in conjunction with the iTube.

The only exception to the moderate price rule for this review is my AAD 2001 stand-mount monitor speakers. I chose the AAD 2001 speakers, rather than lower price speakers I own, because of their resolving ability. They are able to reveal any changes to the equipment played through them.

iTube – $299

The iTube is unlike most other tube buffers I have experienced or have seen in the marketplace. Most other tube buffers are just that, what you see is what you get. A few include a line level preamp section, and a few others will also feature a built-in headphone amp. What does the iTube offer besides the class A active tube buffer, with adjustable gain settings of 0 dB and 6 dB, for the paltry $299 retail? Well, it can also be used as a single source analogue preamplifier, with the same two gain settings. The device includes some interesting features I’ve not seen currently offered by competitors, these being Digital Antidote Plus (DAP) and 3D Holographic Sound, with both using analog filters for operation. DAP is actually several decades old, invented to smooth the harshness inherent in many early CDs, by way of time and phase correction. The 3D Holographic feature is supposed to widen the soundstage of bass frequencies to match the higher range frequencies, with the narrow setting for desktop speakers (switch up) and normal setting for the typical room speaker position (switch down). The 3D feature is off with the switch in the middle.

Included with the unit is an ultra low noise power supply, a pair of generic RCA cables (the kind formerly included with mass produced audio gear), information/warranty card and a tiny screwdriver to facilitate moving the underside micro switches. The information/warranty card describes the various features and functions of the unit. There is a caveat emptor that the iTube should only be used with the specially designed power supply and warns against replacing it with one of your own. In a word, don’t! Darren Censullo told me a few units were damaged as a result of owners switching to a different power supply.

Mr. Censullo also told me the iTube was designed to be sonically neutral, and added that an NOS GE 5670 tube was selected. Well, it happens I have extensive experience with the 5670/396a/2C51 family of tubes. I have auditioned Western Electric, Tung Sol, Raytheon, GE, and several other brands on different tube DACs. The GE was the closest to neutral of the lot. It thus makes sense that this particular tube was chosen to match the design purpose of the buffer. The iTube’s design also does not stress the GE tube, and Mr. Censullo happily said to expect approximately 100,000 hours of life, which almost made my eyes pop out of my head!

A nice design touch is a drilled out hole on the top of the chassis where the dot is on the first i of the silkscreen iFi. This was done to provide ventilation and show the illumination of the GE 5670 tube when the unit has been turned on. I think it’s pretty clever, but an impish move. I would actually like more ventilation on the chassis top since the unit gets quite hot to the touch after being on for several hours, due to inadequate heat dissipation.

I should also add that the iTube requires about 20-30 minutes of playing time before sounding its best.


7 Responses to iFi-audio Micro Series – iTube/Pre-amplifier Review: Part I

  1. Tom says:

    An incredible improvement with the Itube, is to hook up a 9v Astron power supply with a Reality Cable power cord. This improvement will blow you away.

  2. Paul Mah says:

    Hi Tom,

    Thanks for the suggestion. I’m actually using an Astron PS to power my Virtue Sensation amp.


  3. Fred says:

    I thought that I was done buying stuff for a while and then I read this review. Sounds like a great deal. I want one.

  4. Niv says:

    Thanks for the excellent review Paul. I’m thinking of getting an iTube and have read many reviews of it. Only your review mentions “Preamp and buffer on”, which according to the review sounds the best. But none of the other reviews or the instruction manual talks about this configuration, I was wondering could you kindly clarify what you meant by “Pream and buffer on”, as I thought it could be one or the other, but not both at the same time.

    Thanks a lot!

  5. Paul Mah says:

    Hi Niv,

    Glad you enjoyed my review. On the underside of the iTube there is a dip or micro switch which allows the user to select direct mode (iTube circuit only), thus bypassing the unit’s analogue volume control, or tube preamp mode, thus utilizing tube buffer and volume control. Of course, if you select the direct mode, you will need a separate volume control, either from a preamp or source (e.g. CD player with volume feature), because then the unit is a pure DAC.

    If you do get the iTube and desire a warmer sound, I recommend either a Western Electric-or, its Canadian subsidiary, Northern Electric-396a, or Tung-Sol 2C51. Note that doing so may void the warranty. Hope this helps.


  6. Stanley Wahr says:


    Great review and thanks a lot.

    I have the same question Niv asked you and after your answer about the direct mode selection using the micro switch(es) i still can’t figure it out. I’m unfortunatly not that smart. Is it possible you provide a picture from the setting where the buffer and the preamp are both enabled so that I’m 100% sure what I have to do the get it right? I hope I don’t ask to much of your time.

    Thanks a lot!!!

    Stanley Wahr

    • Paul Mah says:

      Hi Stanley,

      The iTube was sent back to the distributor after my review. All you have to do is make sure the dipswitch is set on the preamp position and not on the direct position. Once done, both preamp and tube buffer is on. That’s it! Happy New Year!


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