Reviewing the Linear Tube Amplifier Ultralinear, an Incredibly Rich and Nimble Amp


Let’s start with a little background information. Mark Schneider founded Linear Tube Audio (LTA) in 2015 to manufacture David Berning’s designs. Mark has a background from an engineering career that included management, manufacturing and product design. Mark was the architect behind the fastest document scanner in the world, but he was forced into early medical retirement. After a multi-year recovery, he decided to commit himself to his previous passion, high-end audio. He was drawn to the uniqueness and complexity of David Berning’s designs along with their spectacular sound. It is no surprise when I think of legendary and creative tube amp designers, David Berning is one of the first names that jump into my mind. David Berning personally approves all LTA models to ensure that the build quality met his extremely high standards.


The LTA Ultralinear is the latest ZOTL amplifier designed by David Berning, ZOTL is his Zero-hysteresis output transformerless audio design.  Click here to read about the design and patents. I was really excited to get this latest LTA amp in for review. The LTA Ultralinear outputs 20 watts per channel using 17JN6 tubes, a Compactron-style TV sweep tube that can’t be easily used in traditional transformer-coupled amplifier designs. The ZOTL circuit is able to take advantage of these great-sounding, under-utilized tubes, and in this case, does so in what can be considered the only ultralinear amp without traditional output transformers.

Another exciting thing about this amp is that David designed the amplifier specifically for high-efficiency speakers. It seems David and Mark were talking one day, and Mark mentioned that many of his customers use high-efficiency speakers. So David designed an amp that has a balance between triode and pentode mode. The Ultralinear topology delivers a less forward sounding presentation, which is still very accurate and detailed, and it delivers a big dose of realism.

The power supply is David’s advanced and proprietary switching power supply optimized for audio. The Ultralinear amp has all of the benefits of ZOTL technology such as three times the tube life, 1/3 the heat, a super-wide frequency response of 8hz -60Khz and an under 2-ohm output impedance to play nicely with all speakers. The amp also has a sophisticated speaker protection system to prevent damage to the amplifier and your speakers, if there is ever a tube issue.

Fern & Roby Audio designed the casework featuring front and rear panels milled from slabs of aluminum. They use Cardas RCA, WBT copper binding posts, an industrial toggle switch on the front panel and a stereo to mono switch with all of the markings laser engraved. This is a big step up in looks from previous LTA products.

Listening to Music

I did all of my listening to this amp in my reference system, and I’ll start by saying this is the best Class AB amplifier I have ever heard. The first thing I noticed was that the LTA Ultralinear was the quietest amp I have ever heard; not the quietest tube amp, but the quietest amp. I think this enabled me to hear some of its most captivating qualities; its incredible sense of pace and rhythm, explosive dynamics, and micro-dynamics. I found myself tapping my foot almost as often as I do when listening to live music. The amp is so unbelievably natural that it was hard to think about anything but the music, the glorious music.

So, I’ve let the cat out of the bag. I like this amp. I like it a lot. If you have high-efficiency speakers and you don’t want to spend five figures on an amp that weighs a ton and heats up your room, then you need to hear this amp. There are very few SET amps that can stay in the game with the Ultralinear. It has the ability to magically take recorded music and almost convince you that it’s live! Yes, there are some SET amps that can do this, but the ones I know of start in the five figures and work their way u0.

I think this incredible ability starts with the Ultralinear’s ability to be both incredibly rich and nimble at the same time. The music seems to float effortlessly in space and never seems forced or strained. The bass has a rhythm that enables music to sound very lifelike. Maybe the most important thing about this amp is how tonally accurate it is. Instruments and voices simply came to life in the room when I was listening.  This is an amplifier that pulls off a small miracle in that it has such a big tone and at the same time it has realistic, but not overdone, detail, speed, and micro-dynamics. The system seemed to introduce fewer distractions in the space between me and the performers; a trait I have heard from a select few amps to date. It provided a sensual and emotional experience that drew me into most performances.

This is another of those rare pieces of gear that defies having its sound described by parts; for example by the midrange and soundstage. That just isn’t what you think about when listening to a system that has an Ultaraliner amp in it. So I’m going to write this review in a way I’ve written only a few reviews previously. In this post, I’m going to talk about how my system sounded with the LTA Ultralinear when playing a few important instruments.

Violins, Violas, Cellos, and Most Importantly Fiddles

As I often mention, one of my favorite recordings is Starker’s King of the Cellist, Starker plays Kodaly. This is one of the most beautiful recordings of a cello I have ever heard. I find Starker’s playing comes across as quite intense but full of feelings. The cello is warm, beautiful and quick. With the Ultralinear in my system, there was a great sense of breadth and space, not only around the instrument but also within the instrument as well. It enabled me to experience the excitement of the moment the bow first touches the strings, and, for several seconds after Starker pulls it off of the strings. The sound of the cello flowed with unabashed emotion, and there was something just so right about the sound.

Violins and violas sounded just as good as the cello, very sweet, but never bright or strident. I could easily hear the different layers and textures of the tones of the strings as a bow passed over each of them. Massed strings were full-bodied and extended while never being abrasive.

I love Bluegrass and Gypsy Jazz. Whether the fiddle was played by Stéphane Grappelli or Alison Krauss, the sound in my system powered by the Ultralinear amp was magical.

Plucked Stringed Instruments

It wasn’t just bowed strings that sounded great, so did plucked strings. It made no difference whether it was a blues guitar, a standup bass in a jazz group or a harp in a classical ensemble. It also made no difference whether it was Wes Montgomery, John Williams, Jimi Hendrix, Eric Clapton or even Chet Atkins, they all sounded wonderful with the Ultralinear. The amazing thing was, even with each of their different instruments and styles, they each sounded natural and tonally correct. Thinking in audiophile terms, I think there are three things that are partially responsible for this rightness. First, it’s the way this amp allowed my system to sound weighty and natural without inhibiting the speed of the micro-dynamics. This really enabled an acoustical instrument to sound real.

Very often I’m in the mood for bluegrass and recorded dulcimers, and dobros sounded so much like the real thing with this amp. I grew up hearing a lot of bluegrass, and it’s a musical genre with lots of emotion and incredible micro-dynamics contrasting from all of the different handmade small string instruments. My system, with the Ultralinear driving my Teresonic XR speakers, enabled me to really enjoy recorded bluegrass.

When listening to classical music, plucked strings come from all kinds of stringed instruments. The same traits I talked about above make for some of the most enjoyable classical listening sessions I can ever remember. Whether it was a harpsichord or a harp, they all came to life in my listening room.

I had a friend who is a very accomplished guitarist over to visit, and as we listened to the Melody Gardot Live in Europe LP, he commented on how incredibly real the guitar sounded.  I do agree with my friend as this Ultralinear gets the leading edge, the decay and the tonality of the guitar nearly perfect.

Drums, Cymbals, and Percussion

I don’t know about you, but I find it very difficult to know if a system is accurate when playing drums. As I have shared before, I remember one night at the Columbus Symphony Pops concert when, during intermission, they changed the setup on the stage for the guest that was coming out for the second half of the concert. The difference was between what we audiophiles would call slow, overdone bass with the first set and fast, tight bass with the second set. Now, I ask you, how would you know this if you weren’t there? Yet, there is something I can tell you about both drum sets and drummers. They both carried the rhythm and pace of the music. I think that’s what we always have to consider when judging the ability of a system when it comes to drums. It’s easy to rob all of the weight and substance from your system if you try to get every recording to have fast and tight bass. However, there are few exceptions when the drums shouldn’t convey real rhythm and pace. The Ultralinear, in my system, showed its ability to carry the rhythm and pace.

In several reviews, I’ve mentioned that it has always amazed me at the symphony when the percussionist would strike the little triangle and I could so clearly hear it with all of the other symphony instruments playing. A system with great detail shouldn’t hit you in the face with the sound of the triangle, but you should hear the sound of the tinkle among the other instruments in the orchestra. It’s not that everything should have its own etched-out space, but that you can hear everything distinctly as part of the whole. The more easily you can hear these little percussion instruments, the more natural and orchestra sounds. Now, in jazz, often the same instruments are played by the drummer and are much more forward in the performance. Again, a really lifelike system can do both of these if playing a well-recorded performance. I found the Ultralinear to be very good at enabling orchestral music to sound like a performance.

Horns and Woodwinds

I grew up listening to my father’s Pete Fountain records; he played a great clarinet. I also love to hear the great saxophone players of jazz. On the classical side, flutes and oboes really appeal to me. To truly experience woodwinds, your system must have a great balance from the upper bass through the top-end. Woodwinds move small amounts of air, but this air is a very essential part of their sound. You can hear it when you listen to them live whether you notice it or not. If your system doesn’t let these fine details come through, the music will sound nice but not lifelike. Then, there is the matter of coherency with woodwinds.

There is an incredible flute recording on the Opus 3 test record. The flute and the breath are obviously from one source, and the breath is not exaggerated, but it is definitely there. I hope I’m letting you know how beautiful and lifelike my system plays these instruments with the  Ultralinear.

Horns are more demanding, both in frequency range and dynamics. Most systems struggle with horns. It is just difficult to get the explosive dynamics, the bite and the body of a trumpet or cornet right without sounding edgy or just downright bright. With the Ultralinear in my system, horns were full-bodied and at the same time never edgy or bright.  So it was no surprise that with the Ultralinear big-band music came to life without a hint edginess. My system had the ability to get really loud in the most effortless way. This was one area where this amp brought the sound to the best I have ever heard.

The Organ and Piano

Most people seem to think reproducing the sound of a pipe organ is about how low the bass is in your system. Yes, they can play really deep, but the most unique sound of a pipe organ is air. It’s nice if your system can reproduce the notes from the biggest pipes. The best I’ve ever heard a recording of a pipe organ sound was on my stacked Quad 57 ELS  speakers years ago.

I love to hear a really big pipe organ like the one at Davies Hall in San Francisco. That is, I love to hear them played live, but I’ve most often found it to be such a let down in my home. I think we misunderstand what it takes to reproduce a pipe organ. Who cares if your system can play down into the low 20Hz range? Without proper reproduction of the air, your system will never sound much like a real pipe organ. The sound of organs is all about air, lots of moving air.

It’s also about dynamics. It’s about hearing the hall the organ is being played in and the added weight, decay, and harmonic textures. I got almost all of this with the Ultralinear in the system, and it made listening to organ music truly magical.

The piano may tell us more about a system than any other single instrument. It plays over such a large frequency ranger. It can be powerful or soft. It reacts sonically to how hard or easy the pianist strikes the notes. It can sustain a note, or the note can be quickly released. The piano is also capable of incredible dynamics and micro-dynamics.

It’s not that I listen to piano solos that often, it’s just that if a system can’t get a piano right I find that it usually just doesn’t sound right overall. With the Giscours finishing off my system, I find the piano sounds very right. It sounds very coherent from top to bottom, and it has the speed to keep up with the instrument. I think I spent more time listening to solo piano recordings while the Ultralinear was in the system than I have ever done over the same period of time; enough said.

The Human Voice

The most important thing for my system to get right is the human voice. This is part of what draws me to the Lowther-based Teresonic Ingenium XR speakers. With the Ultralinear, vocals had body and soul. It does this by letting you hear more of the ai4 and more of the vibrato of the voice. It also allows the voice to occupy a more natural space resulting in voices sounding more like real people singing and less like well-recorded voices.  With the Ultralinear in my system, there was the immediacy I have come to expect from my speakers when driven by a great Class A amplifier and great sounding big tones also.

The Soundstage

Maybe the best thing I could say here was the soundstage always sounded natural. It did not bring attention to itself by sounding flat and two dimensional. On the other hand, it did not float instruments in the air in such a way as to make you think about the soundstage more than about the music. It was a beautifully coherent soundstage with great scale and plenty of three-dimensionality. This was about as good as soundstaging gets in my room.

Comparisons and Conclusion

The most obvious comparison I had on hand was the Pass Labs XA30.8, which is close when it comes to rated power and price. Some of the advantages of the LTA over the XA30.8 have nothing to do with sound. The XA30.8 weighs nearly 90 pounds more, it runs very hot, its heat sinks are very sharp and it will make your electric bill go up. There are sonic differences as well. First, the Pass is not as forgiving of recordings that are thin, etched or bright sounding. The Pass is not as rich-sounding, but this can be a positive or a negative depending on your system and taste.

The Pass XA25 is closer in overall sound to the Ultralinear, but it doesn’t have the big tone of the Ultralinear or the same kind of magical midrange. The LTA amp is also much more dynamic. Neither the Pass Labs XA25 or the Ultralinear are as immediate and forward sounding as the Pass Labs XA30.8. Overall in my system, the Ultralinear seems to have just about a perfect balance, and I expect it will for most systems built around high-efficiency speakers.

I think you can tell I love this amp. I love how it sounds, I love how long the tube life is, I love that it’s not very heavy. 

💡If you enjoyed this article, you may also want to take a look at The Beatnik’s review of the MZ3.


23 thoughts on “Reviewing the Linear Tube Amplifier Ultralinear, an Incredibly Rich and Nimble Amp”

  1. Thanks for another excellent review Jack…
    Can we have your thoughts of the LTA Ultralinear vs the First Watt SIT 3 ?
    Thanks! Ken ….The Dog

    1. Thanks for the kind words, Ken. I love both amps, but they are very different in presentation. The LTA is not as forward sounding has a smoother frequency response. The wonderful m SIT 3 is more immediate sounding with a magical midrange and with magical tonal colors. It will totally depend on your speakers to which amp will be best in for you. I think the LTA Ultralinear is the best non-class A amp I have heard on my Teresonic speakers which use Lowther drivers and are 104DB efficient.

  2. Sometime ago, after reading your review of the Pass XA30.8, I took it in for a month-long audition (a friend who was going to Europe lent it me) and much to my surprise it bested a cultish Japanese tube amp I thought would have to pried from my cold fingers. (I was no newbie to your reviews;I had already adopted High Fidelity Cables.) Three plus years of wonder with the XA30.8 I find myself moving to smaller quarters where the amp I can’t lift by myself just doesn’t fit. What to do? Then I read your review of the Ultralinear. Are your ears still golden? Dare I trust the Audio Beatnik again? Of course I should and just in case he’s off his rocker there’s a 14 day home trial. Now, having taken delivery of the Ultralinear and settled in to some early phase burn-in listening, I can say you are at one with your rocker. Thank you again. This amp is all you say it is and actually more–to my ears anyway. If you come across something finer please headline the review “Ultralinear Spoiler Alert” so I’ll be sure to avoid it. Just no fun thinking what could be better than this. And I can easily lift it with one hand.

  3. Any thoughts on how the Ultralinear (20 watts/channel) compares sonically to the Microzotl? I’m considering the possibilities of using with Avantgarde 107 db sensitive Horns in a big room.

    Maybe the Microzotl v2 or v3 in mono? Or maybe the Ultralinear in mono? Or perhaps the Microzotl as preamp with Ultralinear.

    Appreciate any thoughts from listening experience. Thanks!

    1. Will thank you so much for reading The Audio Beatnik. There is a new Microzotl 3 being debuted at the Capital Audio Show this weekend. It is a Microzotl with most of the improvements from their new preamp. It should look nicer and sound better. It will have ceramic circuit boards and a better remote volume control. I hope to have it in about two weeks. I think it will be the perfect product for a pair of 107 dB speakers. As much as I love the Ultralinear amp I still prefer the pure class A Microzotl on my 104 dB speakers. The 3 can also be used as a preamp.


  4. Jack,

    Not sure if you have received the Microzotl 3 yet, but I am interested in your thoughts on using the M3 as a pre-amp with the SIT-3 with a pair of 97db deficient speakers. Any thoughts would be appreciated.

  5. Great review Jack. As the owner of an Ultralinear paired with high efficiency speakers from Daedalus Audio I found your comments very much aligned with my impressions of this amp. I am confident that when paired with the right speakers this amp will rival anything on the market today. The key is using it with a high efficiency design–the amp was specifically designed to work with this type of speaker. When I first put the amp in my system my first reaction was to wonder whether the amp it replaced (a very fine amp that retails for 50% more money) was broken. That is how good the Ultralinear sounds.

  6. Hi, great review and so inspiring. I am curious to know how the Ultralinear compares with the ZOTL 10. I am running the rare beast of a preproduction Ultralinear with stepped volume control and debating (purely for sonic purposes, as I’m currently using just one source), the following:

    1. Keep it and add an mz3
    2. Keep it passive
    3. Buy a Z10 (which I’m pretty sure might sound like an MZ3 /ZOTL 10 combo)

    Would love the Beatnik beat on this. I have to say I’ve never heard a more transparent sounding amp as is.

    1. Thanks for reading our site. I had both the ZOTL 10 and Ultralineasr in house at the same time. I much preferred the Ultralinear. So, I think choice 1 is the winner here.

      The Audio Beatnik

  7. You probably don’t know this, but the Ultralinear is now also available in an integrated, same 20 watts. I know, I have one, maybe the first? My system never sounded so alive.

    1. We knew about the new amp but haven’t had a chance to review it yet. Glad you are enjoying it. And thank you for your comment.

  8. Hi, Could you share your thoughts on a comparison between the Ultralinear and the First Watt Sits? Particularly Sit 2 and 3? I have super high efficiency horns– Avantgarde. Thanks much!

  9. Hi Jack. Thank you for your impressive and very detailed review. It seems to me, that we have likely the same taste musically. Actually I operate the LTA microZOTL Preamplifier in combination with the PASS Labs XA25, which are driving my beautiful speakers Sonus Faber Olympica III with 90db sensitivity. Despite your enthusiastic review of the LTA Ultralinear you are still operating the PASS Labs XA30.8 in your reference system. This confuses me a bit I must confess. The point is, that I’m thinking of replacing my PASS Labs XA25 by the LTA Ultralinear. Would this be a real upgrade, or just a step aside or even worse? I really would appreciate your thoughts about this possible changement. Thank you, with best regards from Switerland, Reto

  10. Reto–I’ll be interested in what Jack has to say but at 90db I would suggest either going with the Pass XA 25 or the LTA ZOTL 40 Reference, which has more power and is designed to handle more difficult loads than the Ultralinear. The key to the magic people are hearing with the UL is pairing it with the type of high efficiency speakers it was designed to drive. LTA has made some significant improvements to the ZOTL 40 Reference which push it’s performance nearly up to the extremely high bar set by the UL when used with speakers of lower sensitivity like yours.

    1. Hi, Jack. This detailed and dynamic and coherent review, though 2018, is extremely helpful to those of us operating long-distance to make amplifier decisions. What say you to Reto and Mark above regarding 90-dB speakers (like my Marten Miles 5s)? Maybe you don’t have a frame of reference, since your focus is the Teresonics. Thanks much.

  11. Thanks for a great review. Just started researching this amp and came across your write up. Currently using a Line Magnetic 508 integrated and I think LTA will be my next amp. Been pretty happy with the LM but looking to take it to another level. I’d love to hear the ultralinear but since I tend to use speakers that range from 85-90 dB efficient (6-8 ohms). I want an amp that will sound great with speakers of this efficiency or higher. Do you think the ultralinear would be enough or should I be considering the ZOTL 40?

    1. Adam, thanks for the question. I’d probably go with the ZOTL 40 given you speaker efficiency. I’m pretty sure if you wanted to try the Ultralinear and it didn’t work, I’m pretty sure the folks at LTA would work with you, possibly on a trial period.

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