iFi AUDIO micro iTube2 Tube Pre-Amplifier, Buffer & Power Amp

I am curious as to if anyone has auditioned this product or currently owns it as a way to get a complimentary tube sound to their solid-state system?

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I own one and quite like it for certain types of music. I use it without gain as a tube buffer which to my ears makes everything a bit less dry, more wet, which to me means that notes are rounder and there is more perceived space around the notes. Stage opens up a bit as well. The effect is more subtle than “omg what a difference” but noticeable. The iTube also has 3 settings for bass enhancement but I prefer the Schiit Loki for that. I never use the 3D function as I don’t care for it’s effect.

From what I can remember, compared to the Schiit Saga+ preamp in active mode I think the “tube” effect of the iTube is more pronounced.

The only down side is that there is no bypass function so if you don’t want the added distortion in your chain you either have to disconnect it or have a DAC and an amp with both balanced and SE connections so that you can switch between balanced (no iTube connected) and SE (with iTube) on your amp.

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Thank you for that info, I like iFi products and saw this today and was curious to learn more about it.

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iFi Audio micro iTube2 Tube Buffer Review

PREAMBLE

If COVID-19 social isolation had any positive side, it was the fact it gave me time to sit down and reflect over my (too many) audio components. As I gazed over my beloved gear, I realized I spent way too much money. Was all this stuff worth it? I still only have one set of ears after all, and I’m not even counting my speakers yet.

0324201532a_HDR by drjlo2, on Flickr

Although I love listening to music through them all, as I gazed to the side, I see the iFi micro iTube2 sitting there doing its tube thing, and it struck me that this diminutive $400 device has saved me tons of money I would have spent on uber amps to optimize all these headphones to the nth degree. Gees whiz, thanks, iTube!

iTube2.3 by drjlo2, on Flickr

THE NITTY GRITTY

I’d rather not dwell on the many different functions of iTube2, e.g. 3D, XBass, SET/PP, preamp/gain mode mainly because I prefer the sound with everything disabled, and much ink has been spilt elsewhere already. Although I am reviewing a tube buffer, which audiophiles tend to frown upon in general (for a good reason), I am a purist at heart, and my system simply sounded the best with every function bypassed, with the lone GE 5670 tube in its default “studio” setting in the middle toggle position.

(From ifi website)

iTube2front by drjlo2, on Flickr

HOW DID iTube2 SAVE ME MONEY

The Stax SR009 is infamous for being unforgiving, sterile, bright, stealing your lunch, and cheating on taxes, etc. I’ve listened to them over the years through various 'stat amps and speaker amps/transformer, and to this day, I had not found that mythical perfect amp. The Stax faithful swear by the DIY T2 amp for SR009, but that is a 5-figure DIY unicorn. Next best compromise has been to run them with 2A3, 300B SET tube amps via transformer, and while the midrange with certain amps are TO-DIE for, low-watt SET’s do not take you all the way to the promised land in terms of bass definition and dynamics or ultimate detail resolution.

Of the amps in house currently, the one with the most detail resolution and bass prowess is an ICE Edge 1200AS2 class D amp. Yes, class D steals your lunch and cheats on taxes, too. Actually, on speakers, this amp sounds superbly neutral, detailed, smooth, and clean. But when powering something like SR009, the combo sounds too squeaky clean although detail and dynamics are off the charts.

Inserting the iTube2 before the amp introduces the right amount of even-order harmonic bloom, texture and richness through vocals, while slightly smoothing/rounding off leading edges. Those who own SR009 can likely imagine how beneficial these changes are to SR009. The end result allows one to listen past SR009’s cool character while fully enjoying the incredible resolution, speed, and dynamics as well as that special electrostat sound. Through this setup, vocals and instruments feel like sparkling water bursting open cheerfully from their bubble of harmonic air in that electrostat style. This unique sound signature IME cannot be duplicated with other driver technologies and is what got me into 'stats in the very first place when I listened to the mighty Orpheus.

0326201714 by drjlo2, on Flickr

Well, is the iTube2 only good for Stax SR009 then? It also saved me money with Abyss 1266 Phi TC. I love the Abyss, but there must be a reason JPS Labs demo’s the Abyss on $6K Xiaudio Formula S+Powerman combo. Even then, there are Abyss owners who prefer uber expensive tube amps even over the solid state duo. Again, the ICE Edge amps sounds good with the Abyss via my DIY cable to power off the speaker posts. But it was the type of sound one admires rather than immerse into. More often than not, I found myself reaching for my 300B SET amp for Abyss. Things change when I insert the iTube2 in the class D chain, however. Now the jury is out on which amp can provide more immersion and pure enjoyment. 300B SET sounds, well more 300B-like, in a wholly different unique way from how electrostats stand apart. 300B afacionados out there are probably nodding their heads at this point. iTube2 does not turn the amps into 300B SET sound, so don’t be buying iTube2 to turn your solid state amp into SET amps. It adds just enough tube bloom and texture to make music sound more intimate, human, and involving with acceptable sonic compromises elsewhere.

THE DARK SIDE

So what are those compromises? Any device added to the signal chain adds distortion, and iTube2 does not defy the laws of physics; signal does not pass through this device with 100% transparency. But why would I buy it if signal didn’t change? The upside has been described, and the downside is a slight loss in detail, clarity, and bass definition. Luckily, the amount of loss is truly slight when compared to how much is gained in voluptuousness and texture, likely acceptable to even purists like me. One can maximize these benefits by minimizing extra cabling whenever possible.

Another consideration is that an audio device is not going to work universally for everybody in all situations. I tried the iTube2 feeding Jotunheim R for Raal SR1a ribbon headphones, and surprisingly, I preferred the results without the iTube2, which seemed to interfere with Raal’s studio monitor like signature. The extra interconnect cabling needed between iTube2 and amp does influence the sound significantly, so I even got rid of the interconnect using some adapters. Better, but still not quite what I wanted to achieve. SR1a is so new to the scene with very limited direct amplification choices, so I look forward to the brand new Raal HSA-1a amp and hopefully others. But dear Lord, why are good stuff always so expensive?

(Example of how to bypass extra cabling between iTube2 and Jot R)
0327201820 by drjlo2, on Flickr

Now on to slightly less wonderful news. My speaker systems didn’t seem to benefit much from having iTube2 in the chain. This leads me to believe iTube2 works its best magic when it comes to super neutral, clean type of headphones with amps leaning in the same direction. If your headphone or speaker system is already tweaked and dialed in to the exact balance you like, it’s easier to upset that balance than enhance it. This is not to say somebody else will have the same experience as me with their setup, however, so YMMV as usual.

WISHLIST FOR iTube3

This is a selfish wishlist for a future product that I would buy in an instant at twice the current price:

First, a bypass switch would really help so iTube can be left in the system even when the tube effect is not needed. Also, OCD audiophiles always prefer a quick way to A-B the differences. Additionally, the SET and Push-Pull mode don’t really represent the best of the breed sound, more like a taste of them only. I would much rather just have the middle “classic studio” setting but with a knob to dial in the amount of tube effect. That would be awesome.

Secondly, the toggle switches need to be remade so that bypass/neutral position is at bottom for all 3 switches, with increasing effect as toggle is switched up once, then twice. For example, currently from bottom to top, XBass toggle goes bypass >+12dB >+6dB and 3D goes Plus > bypass > 30 degree Plus. And the letters are way too small to read.

Thirdly, tube rolling is unnecessarily difficult and voids warranty. I understand iFi wanted to keep their products in same chassis profile and hide the tubes inside, but half the fun with tube gear is in tube rolling. I understand iFi considers the stock GE JAN 5670 tube to be already premium and as good as they come, but sometimes an audiophile just needs to find out for himself. Yes, I would love a hole on top where tubes stick out and rolling doesn’t void the warranty. This leads to…

TUBE ROLLING FOIBLES

iTube2.4 by drjlo2, on Flickr

iTube2.5 by drjlo2, on Flickr

Some tips for those who dare void their warranty. The daughterboard on top would appear to hinder tube rolling; however, there are no screws, and it just pops out from a single connector socket. This really helps because the tube socket is not the usual variety and grabs the tube pins with death force, feeling like they are soldered on initially. Firmly grab the board on the sides with your left hand and apply strong, steady force up on the tube with the right hand while applying micro wiggles, and the tube will eventually come out. Tubes do go in easier, but I applied some Caig ProGold on the tube pins for future ease of rolling. The board dimensions look too small to accomodate the taller Bendix 6385 or other 6N3P tubes, so the hole on top would really help, which will double as vent holes because iTube2 gets pretty hot with only a pinhole in the chassis.

More tips. You will see a skinny silicone band on the stock tube. My first thought was, “Boy, a ring that thin couldn’t possibly be effective as tube vibration dampers.” Don’t throw it away because its purpose seems to be to prevent the tube from rubbing on the small chassis. There is literally zero air between the tube/ring and metal chassis. Also, as you reinsert the board, there is no way to prevent the edge of the chassis from rubbing on and moving the ten tiny toggle switches on the bottom of the board, so make sure to reset the tiny toggles after assembly. And there seems to be a metal pin on the bottom of the board that prevents the board from going in further. If this happens, don’t force it and find the little pin and gently nudge that inside.

FYI, above review is solely based on the stock GE JAN 5670 tube, which does seem to be an outstanding tube as iFi promises.

PROLOG

So should you buy one? I think if you read this review so far, you probably already know the answer for your particular system and personal tastes. $400 is not exactly pocket change, but then again, I have bought $2000/pair 300B tubes before. Nope, I’m not too proud of that kind of purchases.

Lastly, some well-heeled audiophiles may think, “Hey, I already own an expensive tube preamplifier. I will just use that instead of iTube2.” This may or may not be true. For example, I own several preamplifiers, and one of them is a uber-modded tubed preamp. Its switches have been bypassed, volume control converted to shunt mode, caps changed to teflon caps, etc, all in the name of maximizing transparency. Ironically, this preamp does not add enough tubiness to replace iTube2. It does its intended job of providing gain while remaining super clean and adding just a whisper of tube sweetness and space, but iTube2 adds significantly more tube sound, just enough for Stax SR009 and Abyss.

Then what about using less costly tube buffers or preamps? I have tried some of these in past, and while they can sound quite tuby, they tend to throw away the baby with bathwater in terms of detail preservation and speed. Perhaps you have a tube device that walks the fine line, but iTube2 has already hit the line for an affordable price IMHO.

Happy listening!

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Great review. It certainly gives us a taste of what it’s like. But the fact that it’s so difficult to tube roll is a great shame.

1 Like

Awesome, Review. I own v1 and it worked out for me for a while. I have outgrown it and now sits in my drawer :slight_smile: