[SFDude]

JLM, good to hear the flooding damage issues are mitigated, although it is a headache to deal with.

Also, I'm curious if the DSPeaker isn't already doing some signal processing that sort of neutralizes or negates the effects of iTube2. I heard the effects of this unit at RMAF a few years ago and it was noticeable, also doing some of the similar things that iTube2's 3D mode does (although via different methods).

BTW, just got back from a work trip so not much time to listen and do some more observations on the unit. Ready to ship off to JakeJ next tomorrow and I'll finalize my last observations.

-dave

[JLM]

Dave,

Don't know, it's the only DAC and/or preamp I have on hand.  The DSPeaker also has DSP capabilities which I do use, but unaware of anything that would cause it to not "play nice" with iTube 2.  Can you be more specific? 

[SFDude]

Don't know, it's the only DAC and/or preamp I have on hand.  The DSPeaker also has DSP capabilities which I do use, but unaware of anything that would cause it to not "play nice" with iTube 2.  Can you be more specific? 

I haven't dived into what the iTube2 is doing but it seems to be apply analog signal processing which may be doing something with the signal coming out of the DSPeaker unit (which is applying digital signal processing) that is causing odd effects? It would be interesting to see how this unit sounds when inserted between a modern home theater preamp (that processes a bunch of effects in the digital realm) and power amp(s).

I'm speculating here so don't take anything I'm suggesting as definitive.

[konut]

Earth to Pez. Please read your PMs.

[brother love]

Pez,

I didn't get a response to a PM sent to you yesterday as well, so to be on the safe side ...

Received an email from you yesterday with instructions for last reviewer Ted to sent it to me next.  As per our prior correspondence a couple months ago, please remove me from the tour list since I have already purchased an iTube2.

Since we have had some "gremlin issues" with you not receiving my Yahoo email responses for some bizarre reason, I wanted to be sure that this gets caught quickly (fyi, I sent an email to Ted also).

Thanks

[konut]

I'm sure this will all get sorted a some point. Meanwhile, I get the extended audition. 

[Pez]

Hey guys,
Sit tight for now. Sorting some things. Sorry for the email snafu. We will get things moving shortly.

[konut]

Hi Pez,
       I get uncomfortable sitting tight. I'm a loosey goosey sort of guy. I hope that's OK.

[konut]

I'd like to thank Pez and AMR for the opportunity to audition the iTube 2. I need to apologize for this review because I was not able to utilize the iT2 in an optimal configuration of my setup. I am missing my Bryston BDA-1 DAC which is in for repair with an unyet determined problem. For the review my system consists of: Sony BDP S580 Blu Ray player(which is usually just used as a transport).  Sony XDR X1HD tuner.  Sony KA1ESA cassette deck.  Tortuga LDR1 passive pre.   Wyred4Sound SX500 monoblocks.  SP Tech Timepiece Minis with Aether Audio Black Boxes. VMPS Super tweeters. AntiCable speaker cables. Sweetspot Reveal interconnects. The super tweeters sit atop the speakers, in the same plane as the other voice coils, firing toward the back wall.

As you can see, not a tube in sight. To say that my system is dry would be an understatement. When I fire it up the ambient humidity drops by 30%. The Sahara desert calls up and asks "WTF?". I wanted to see if this gadget could get me some of that tube goodness everyone talks about. i am/was scheduled to review the Tortuga Audio Tube Buffer. The fantasy was that I'd get both simultaneously and pit them against each other in a Texas Steel Cage Death Match with the winner pounding its chest and roaring at the top of its lungs. Alas, it was not to be. I did get the Tortuga a few weeks ago, explained to Morten the problem with my DAC, and he graciously agreed to send the unit at the end of his tour by which time I, hopefully, will have my DAC back.

The main problem I had was using the crappy analog output of the Sony Blu Ray to evaluate the iT2. It suffers from the usual digital glare. It was readily apparent with the Tortuga buffer as well as the iT2. They could not "fix" that. There are a couple of CDs that seem to not suffer as much from this so those are what I used to put the iT2 though its paces. The iT2 was inserted between the Tortuga passive pre and the amps. I played Sergio & Odair Assad Play Rameau, Scarlatti Couperin, and Bach. I started with the buffer only mode in the SET position.The first thing I noticed was that the unit shared the same characteristic as the Tortuga buffer and Paul's grandfather in A HARD DAYS NIGHT. It's/he's very clean. Had it been otherwise the review would have ended then and there. I cannot tolerate distortion. (Wait, I can see that bubble over your head where its written "Then why are you using the crappy output from the Sony?". Well, I gotta use SOMETHING!) Next I noticed that the full frequency range seemed to have more presence. The lows seemed more solid, the midrange had more detail, and the high had more authority. I'm guessing that this is the function of a better impedance match. Then I sampled the functions of the 3D Holographic switch. As advertised, this separated the 2 guitars farther apart. I could see this as being useful in a desktop system, and at the extreme 30 degree+ setting, for some enjoyable late night, lights down toasted/baked experiences. There seemed to be a slight touch of ringing at this setting. Then I tried the XBass+ switch. This added some low end body to the acoustic guitars that was pleasant. I could see this switch as being completely dependent on volume, the particular characteristics of ones speakers,  and the particular recording. I found no sonic anomalies with this in any setting, suffice to say that with my speakers on some recordings the bass was lumpy. A transparent loudness switch was my impression. The next disc was Sade Love Deluxe. The striking thing was the rendering of the vocals which had more texture and clarity. Fundamentals and overtones more distinct yet smoothly blended for a more natural sense of the voice. I tried the different SET, middle, and push pull setting but I'm afraid the deficiencies of the Blu Ray output obscured any differences. I had no real preferences.
      The next day I hooked up the Sony tuner. This source has a much better analog output than the Blu Ray. It was easier to hear the effects of the various setting positions the downside being I could not repeat the same recordings and was at the mercy of whatever programming that was on at the time. I'm blessed living in an area with an excellent jazz station, KNKX, and a descent college radio station , KUGS, that plays a lot of contemporary music. I enjoyed the presentation with the iT2 in the system without the glare of the Blu Ray.
     A couple of days later I decided to fire up my cassette deck. I have a bunch of recordings that I made in college when I worked at the coffee house in the student union. One of the downsides of having a passive pre was that the cassette decks' anemic output could not really present the music to its best advantage. I set the dip switches to the +9db position. It was great to hear Leo Kottke, Sonny Terry & Brownie McGee, and Jonathan Edwards again in all their full throated glory! I was also reminded why I adopted CDs when they appeared. The hiss from cassettes, even though not especially apparent during the most of the music, gets annoying during quiet passages.
     I enjoyed my time with the iTube 2. I could see this unit as being a superb tool in a desktop or project studio setup.

[konut]

Addendum: 

Neglected to post a pic.




Sorry for the fuzzy picture which obscures the protective layer of dust on everything.


Pez kindly allowed me to keep the iT2 a few extra days so I tried the it in preamp mode dispensing with the Tortuga passive. It sounded great! It was only when I went back it the Tortuga, only,  that I noticed a slight increase in clarity but missed the increased heft that the buffering offered. The other thing was I realized how much I value the balance control and remote function that the Tortuga supplies. If I were just starting out the iT2 would be at the top of the list for value and quality and the feature set that it provides. 

[Rusty Jefferson]

Sorry for the delay getting this review in.  I appreciate the AMR/iFi folks sending out this piece of gear for evaluation.  Very generous!

I've been most interested reading about other members systems, and in particular seeing photos.  The photos help give peoples comments about the iTube and how it works in their system perspective. 

Although my system does do some things well, it does not do probably the most important thing a quality stereo should do, and that's recreate a believable 3 dimensional sound field of a live un-amplified acoustic performance.  One that is completely transparent so the listener has no idea where the music is coming from, and instruments can be placed both behind and in front of the speakers themselves, as well as beyond their width.  Rather, it's quite 2 dimensional.  There is front to back depth, and width, but because of the speaker design, no 3rd dimension. 
My speakers are control room monitors (UREI 813C) and were intended to be mounted in an infinite baffle. Because that wasn't possible in my home, I needed to build a pair of subwoofers to reinforce low frequencies.



The trade off for not getting 3 dimensional sound is I do get big, effortless, dynamic, coherent sound.  Always a trade off in this hobby. At the listening position, it's measured remarkably flat from 25hz-13khz. Bass is solid with no hint of tubbiness, midrange is as natural as I've heard, and highs are smooth and clear, though rolling off above 13khz. I never considered horn speakers till I heard these.

I won't go into all the details, but I was growing concerned that bi-amping (the subs are passive) with 2 solid state amplifiers that have modest input impedance (33k ohms each), and an active tube preamp with normalish high output impedance (3-4k ohms) might not be the best combination.  I didn't need the gain of the active pre (speakers are 102db) and I am not a fan of transformer coupled tube amps. I was able to borrow a well designed solid state preamp, which got me a nice low output impedance, and sure enough dynamics and drive improved immediately, but the sound was too hard for critical listening.  I then borrowed a Berning ZOTL preamp which has similarly low output impedance (<2ohms) and is 12au7 based. Okay, now I'm getting the best of both worlds, except for the cost. A little interweb research and talking with a couple friends in a local diy club turned up the idea of a buffer, and within short order I had an iTube on the way.

I initially installed the iTube last year between my PS Audio Directstream DAC and the amplifiers without a preamp, as the DAC has volume control. Results were good. Not great, but good. Then, I borrowed a First Sound passive preamp and installed it between the DAC and the buffer.  Magic, much to my surprise, that adding a passive and another set of interconnects could make such an improvement. The system now had the drive and dynamics (low output impedance), plus the natural richness of a quality tube preamp (iTube), and whatever magic happens in a passive preamp (that I don't understand). 

So, when this tour came up I thought I'd sign up and see if there will be any difference in my system with the iTube2 since the original was so successful for me.  I did several days of listening evaluation, and then took it to a friend's home for measuring. I only examined it in the 0 gain buffer mode.  I cycled through the preamp and 9db buffer modes with the original, but quickly preferred the 0 gain buffer.

I've always used the original iTube without any 3D filters and the Digital Antidote turned off.  In my system, that has the most natural presentation.  The 3D filter in particular, just blurs instruments (piano in particular) in the image.  So, I decided to start with the 3D in the "disengaged" position, Bass boost "off", and output in "Classic".  After many cycles through the same tracks at the same levels, both alone and with my wife helping do blind comparisons, we both came back to this same starting point. We felt is was the cleanest, most natural of the combinations. This sounded very similar to the original, with just a little less gain in the high frequencies.

The SET and Push/Pull output settings each sounded more restricted in the high frequencies than Classic, with SET being the most restricted. Bass did not appear to change at all with any of the 3 outputs. Fortunately for me, these observations were apparent when we measured it. Because of what we were perceiving as restricted highs, the iTube 2 did open up more of the music library for casual listening.  Many of the poorly made cds of our youth were far more enjoyable.  Still not good, but more enjoyable.  We regularly switched from Classic to Push/Pull when a bad (but beloved) cd was played.  The Xbass wasn't necessary with my system, but I could see this being a good filter for smaller systems, or perhaps headphone use. And like the original, the 3D settings were just a distraction here, including the "default" setting. Only the "disengaged" setting seems appropriate.





The buffer measured extremely well.  Almost perfect square waves from 20hz-20khz, even when driven far harder than they would ever see in use.  The measured output impedance was what is listed as the "corrected" impedance in the specifications, 160 ohms.  There was a subtle, but distinct reduction in gain of higher frequencies for the P/P and SET output settings compared to Classic, but no other change to the square wave. That squared with what we were hearing with music.  Some of the engineers present had some questions about how the filters are being implemented.  Don't know if that's something AMR can share.  My assumption when I purchased the original iTube was that it was hybrid, tube input stage, transistor output stage.  The iTube 2 specs do say it's a tube output stage, but the engineers wondered how they achieved the low output impedance with a tube output stage, without transistors.

In looking at distortion in the Classic setting, it certainly appears to be a hard clip, typical of an op amp being present.(?) Distortion in all 3 output settings is very low.
 


Clipping in the SET output does seem more tube like.


I couldn't be happier having the iTube(s) in my system.  It is a wonderful match for my system, is dead quiet, and reasonably priced.  I could see how it may not be appropriate for all systems, or may not positively influence all systems, but I'd imagine more than not might be improved by adding one. It has excellent measurements, appears well designed and implemented. (Insert thumbs up emoji here)

My system consists of:
Music stored on a NAS, uncompressed FLAC>Sonore SSR renderer>PS Audio Directstream DAC via i2S>First Sound Passive preamp(I still need to pay for)>iTube buffer>split output from the buffer, 1 output to full range amp (Parasound Z Amp or Berning SET) 1 output to an active crossover for the subs>UREI 813C full range, 2x8 cubic foot subs with 2245h JBL 18" woofers.

All analogue, digital, and speaker wires Omega Micro/Mapleshade, except 1 pair of Dueland analogue between DAC and preamp.

[Pez]

Thanks for the thorough review! I have asked our guys to give some answers for the more technical aspects of your review. Most of our guys are in Munich at the moment so bare with, we should be able to get an answer soon.

[Pez]

On behalf of the iFi I just want to say thanks to you all. THIS TOUR ROCKED!!!!
 

This tour was my first major kick off on Audiocircle and I can't tell you how awesome it has been to see it take off here and other places because of this tour! So thank you all for taking the time to give us your impressions of this awesome piece. As a thank you we are going to raffle off both iTube 2s.

THAT'S RIGHT BOTH OF THEM!!! In order for me to do this I need to make sure all reviews are in!!!!!11!1!!1 If you were on the tour and have not finished your review yet, now is your last chance to participate in the raffle by submitting your review! Winners will be picked at random. One for east coast another for west!

[WireNut]

I was scheduled for the tour but didn't receive the unit.
I was hoping to compare it to my Yaqin CD3 tube Buffers.

[SFDude]

This tour was my first major kick off on Audiocircle and I can't tell you how awesome it has been to see it take off here and other places because of this tour! So thank you all for taking the time to give us your impressions of this awesome piece. As a thank you we are going to raffle off both iTube 2s.

THAT'S RIGHT BOTH OF THEM!!! In order for me to do this I need to make sure all reviews are in!!!!!11!1!!1 If you were on the tour and have not finished your review yet, now is your last chance to participate in the raffle by submitting your review! Winners will be picked at random. One for east coast another for west!

Wow. Not only do a bunch of us get to try out new gear from iFi, you're RAFFLING OFF the demo units? This is how a company wins customers, one at a time. I had been actually thinking of getting an iFi Phono 2 last week to replace my current phono (it's MM only) as a result of the great build quality of the iTube 2 and being affordable.

Nicely done iFi. I'm also wondering if Pez had something to do with this raffle business also. 

-dave

[Pez]

Dave,
You are all to thank for this. Because despite my best efforts, this tour went off without a hitch! and We have you ALL to thank for this!

We love you guys and count ourselves lucky to have fans like you! Keep rockin' into the weekend AC! 

[WC]

My audio system before the iTube2 was a Raspberry Pi to Schiit Modi USB DAC to Marantz SR-6005 AV Receiver to ACA Pass Amp monoblocks to Boston Acoustics HD-9 speakers. I don’t run a sub.

I tried the iTube2 at first as a buffer. I inserted it between the DAC and the Marantz. There appeared to be a little more weight to the music with the buffer inserted than without it, but it was just a slight change. Next I inserted it between the Marantz and the ACA’s and had a similar slight improvement. I tried out the listening modes and did not like the bass boost. Could not notice a perceptible difference between the tube modes.

I next tried it as a preamp. This is where I noticed an improvement in my system. When set as a 0dB preamp, it had much improved resolution and clarity. I could make out the instrument separation much better. Most of the songs sounded better, but there were a few that this clarity made difficult to listen to. Over all I liked operating it as a no gain preamp (other than having to get up and change the volume and only having one input).

I changed the setting on the iTube2 to the 9db gain preamp. I having been running this for most of the last week. I compared this setting to the 0 dB gain setting, by playing some of the same albums. Overall the sound had less separation of instruments and less clarity than the 0 dB gain setting, but the songs that were difficult to listen to before sounded better. Music seemed a little more congested. The sound was slightly better than using my Marantz as a preamp.

I listened to a lot of my favorite albums during the time I have had the iTube2. They sounded good. I generally listen to folk and rock music.

Would I buy one?

I don’t know. I am currently in the process upgrading my system by building a new amp and DAC and intend to build a preamp and new front speakers. I may have a greater need for it in the future, but I won’t know that until later since I am changing just about the whole 2 channel music train.

Thanks Jason and iFi for the opportunity to try out the iTube2. I will post a pic tomorrow.

[charmerci]

I thoroughly enjoyed listening/comparing the itube2 - a nice component in a small package. 

[WC]

Here is a pic of the iTube2 in my system: