ZOTL Ultralinear+ Amplifier
ZOTL Ultralinear+ Amplifier
The ZOTL Ultralinear+ is the latest amplifier design by David Berning: the first ultralinear amplifier not limited by traditional output transformers.
Note that we are now using Cardas speaker binding posts, not reflected in the photos above.
ZOTL Ultralinear+ Power Amplifier
LTA’s most detailed amp, refined amp
Micro-detail across the frequency range increases realism and encourages long listening sessions
20 watts per channel, perfect for speakers 88dB or above
The latest amplifier design by David Berning. Striking a balance between triode and pentode mode, the new ZOTL Ultralinear+ amp provides the unique advantages of each while maintaining all the benefits of the ZOTL circuitry.
The ZOTL Ultralinear+ amplifier delivers uncolored detail and realism without sacrificing natural mids and powerful, controlled bass. The ZOTL Ultralinear+ is our most detailed and refined amp. Many listeners compare the presentation to SET amps, while offering much more power.
Listeners enjoy the less forward, distortion-free presentation that is “more pleasing to listen to” the Ultralinear offers.
What’s New in the Ultralinear+ Version
“There is tonal sheen, midrange elegance, and startling, controlled dynamics like never before. The “Plus” upgrades reveal more emotion in the music.”
LTA is proud to announce the next generation, and first-ever upgrade, of the Ultralinear flagship amp. Introducing, the ZOTL Ultralinear+ power amplifier.
After trying over two dozen component combinations, and countless hours of listening tests and comparisons, the new ZOTL Ultralinear+ power amp improves the tone and texture across all frequencies, and there is more detail and clarity around the performers.
These sonic upgrades are achieved through adding a massive 100,000µF of additional capacitor storage and changing the resistors in the audio path to non-magnetic Audio Note Tantalum and Holco Metal Film resistors, each type and value specifically chosen for each location.
Reviews & Testimonials
Review by a UL+ Beta Tester and LTA Customer Mark D.
As I said at the outset, the standard UL was the best amp I’ve ever heard in my system. Unbelievably, the UL+ makes an even more compelling presentation with better timing, spatial cues, separation of musical lines, bass weight, and tonal realism through the lower midrange. If you have somewhat high efficiency speakers like mine the UL+ is probably as good as it gets for amplification--regardless of price.
Customer Bill S. on the “Plus” version:
I was expecting to hear an improvement, but was not prepared for what I heard last night. Mark had mentioned that an upper-mid smear had been alleviated and that there was increased musicality top to bottom and I agree, but still was unprepared. What I heard last night was simply a sound that was more organic, fleshed out and much more musically correct, but at the same time more relaxed and easy to listen to. The differences were not subtle at all. By comparison the music in my room went from: “that’s nice - background music” to “you have to sit and listen to this!” because it sounds so damn good. Bottom to top the sound was more alive and full, with much more drive, punch and control. I didn’t want to turn it off.
After about 4 hours when I did turn it off and walked into the next room my wife said “what are you all smiles about”? I think she knew.
Listening Notes from LTA’s Director of Sonic Quality
Yes, that is a real job title - some people have all the luck - and along with a cadre of test listeners, it’s their job to make sure the sound of the Ultralinear+ upgrades keep the LTA sound our customers love while raising the bar in the right areas.
Whether you are Sunday morning classical, late night jazz, or sweaty rock club listeners, everything comes out sounding sweet and immersive with the “Plus” version. There is tonal sheen, midrange elegance, and startling, controlled dynamics like never before. The “Plus” upgrades reveal more emotion in the music.
We’ve found that with the “Plus” update, listening fatigue is a footnote of the past, no matter the source. Even the most challenging torture tracks become immediately palatable and better yet, unskippable. When pushing to "live sound" decibels, instruments and vocals stay in place and simply get more vivid and real instead of breaking up or becoming shouty (suggesting the listener be more reasonable with the volume control.)
Whatever your preference, you'll find new appreciation for your all time favorites and fall in love with the latest new releases.
Upgrade your Ultralinear power amp
Existing Ultralinear power amp customers can upgrade their units via our Ultralinear+ Upgrade Program.
“It’s fair to say that the ZOTL Ultralinear amplifier is a smashing sonic success.”
Reviews & Testimonials
This is an incredibly detailed amp. I mean detailed in a good way, without sounding analytical in the process. Its ability to unravel complex passages resulted in a supreme sense of spatial clarity. This was a function of preserving transient decay into an exceptionally low noise floor.
The results confirmed strong similarities with the SIT-3 in detail resolution and harmonic textures, though the UL was more dimensional, especially with respect to soundstage depth.
It’s fair to say that the ZOTL Ultralinear amplifier is a smashing sonic success.
Stereo Times “Most Wanted Product of the Decade”
What makes this amplifier so special is you would swear you’re listening to a SET 2A3 amplifier because of its beautiful tonality/colors and spatial qualities, yet the overall dynamics and bass control rival a much more powerful solid-state design.
The Linear Tube Audio ZOTL Ultralinear is quite remarkable. It fools you into thinking that it's a reference SET for its ability with tonality and color. It provides rich, vibrant and gorgeous timbres along with an overall silky smoothness that just floats the music into the room in relaxed fashion. However because of its overall speed, dynamics, lower bass extension and control you know it couldn't be a flea-power SET.
Think of the ZOTL Ultralinear amplifier as a world-class SET for its inner glow of gorgeous color/timbres plus the sense of aliveness and dynamics of a more powerful push/pull. This amplifier would be welcome in any system with standard speakers and listeners who prioritize beautiful tonality and timbres, first-rate imaging and the aliveness and 'speed' of live music.
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.
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 up.
Audiogon Forum Post (LTA Customer with Daedalus Speakers)
I am saving perhaps the best for last here, I was completely blown away by the spacious soundstage this amp produced. It transformed the soundscape, adding multiple layers of depth and copious cushions of air around the performers. Everything became completely three dimensional in a way I have only heard in rooms that allowed for a much better setup than mine. It is this type of spatial realism, when combined with such vivid, realistic tonal color and transient fidelity, that makes the Ultralinear so intoxicating--so NECESSARY.
Plays nicely with others
The ZOTL Ultralinear was specifically designed with high-efficiency speakers in mind. Yet a super-wide frequency response and less than 2 ohm output impedance means it plays nicely with all speakers.
Stereo + mono, at the flip of a switch
The ZOTL Ultralinear outputs 20 watts per channel. Need more power? Like all of our power amplifiers, it can be used as monoblock or stereo amps at the flip of a switch.
“I was completely blown away by the spacious soundstage this amp produced.”
Unique tubes, unique amp
The ZOTL Ultralinear uses 17JN6 power 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, inexpensive, and widely available tubes.
Never buy another set of tubes
Most tube amplifiers run through tubes every 1,000-2,000 hours. That sounds like a lot until you consider that we estimate tube life for our amps to be in the 10,000-20,000 hour range. Why? Because we use ⅓ the current through the tubes, which results in lower heat and dramatically longer tube life.
“The Linear Tube Audio ZOTL Ultralinear is quite remarkable.”
Tube tone + solid state detail
Traditional tube amps are known for their liquidity and linearity, but their “warmth” masks details and can sound thick. Solid state amplifiers give you that detail, but can be “clinical.” ZOTL amplifiers give you the best of both worlds: beautiful tube tone with the clarity of solid state (while being entirely tube-based.)
Looks as good as it sounds
The low-resonance aluminum chassis of the ZOTL Ultralinear amplifier is designed and manufactured in Richmond, Virginia, by the award-winning industrial design crew at Fern & Roby. Sturdy toggle switches and machined aluminum front and rear panels exude quality.
Patented perfection
The ZOTL Ultralinear amplifier is based on David Berning’s patented ZOTL technology, the only advance in tube technology since the 1950’s. For a technology to be patented, it must be deemed “new, useful, and non-obvious.” We think that sums up our approach quite nicely.
Premium components = premium sound
If you use cheap, generic parts, guess what kind of sound you’ll get? That’s why we use only premium, name-brand components. Belleson regulators. Vishay Dale resistors. Mundorf caps. Typically, these are names you’ll only hear in amps that cost $10k or more.
“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!”
Made in the USA
Every LTA product is designed and built by hand in Takoma Park, Maryland, by a group of technicians who are also musicians, audiophiles, and music lovers. Some of whom have been with us since the company’s earliest days.
Quality assurance
The ZOTL Ultralinear amplifier is hand built by technicians with years of experience building the complex ZOTL circuits. All our products are backed by a 2-year warranty and a 14-day no-questions-asked return policy.
Speaker Recommendations
LTA amplifier owners have found great enjoyment using their amps with a variety of speakers outside of the below ranges. The below are guidelines, not rules.
Critical listening environments: 88db sensitivity and above
Smaller rooms / lower volume levels / non-critical listening: 85db sensitivity and above
If you have questions about your specific speakers, chances are someone we know has tried them. Don’t hesitate to reach out with questions about your specific setup. Also, don’t forget we have a 14-day no-questions-asked return policy.
Specifications
Inputs: One pair L & R Cardas RCA
Outputs: One set of stereo Cardas speaker binding posts
Amplifier class: Push-pull class AB
Power output: 20 watts per channel @ 8 ohms
Sensitivity: 1.2V RMS for 20 watts output
Frequency response: 8hz to 60khz - +0, -.5db
Output impedance: 1.6 ohms
Input impedance: 50k
100V / 120V / 240V operation: Auto-switching
Hum and noise: 94dB below full output (measured between 20Hz-20kHz)
Gain: 21db
Stereo/Mono: Switchable Stereo-Mono
Dimensions: 17 inches (43 cm) wide, 5 inches (12.7 cm) tall, 13.875 inches (35.2 cm) deep
Weight: 17lbs
Tube complement: Two 12AU7 and two 12AX7 input tubes, four 17JN6 power tubes - Autobias for all tubes. All tubes NOS.
Details
The ZOTL Ultralinear is the latest ZOTL amplifier design by David Berning, utilizing his Zero-hysteresis output transformerless audio design and his unique power supply.
The ZOTL Ultralinear amplifier 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.
David designed the amplifier specifically for high efficiency speakers. A balance between triode and pentode mode, the ultralinear topology delivers a less forward presentation which is "more pleasing to listen to". The ZOTL Ultralinear delivers accuracy, detail and realism. Pianos sound like pianos. The bass is controlled but fluid. Very transparent, no hum and very dynamic.
The power supply is an advanced switching supply optimized for audio that only David Berning deploys.
All the benefits of ZOTL technology, including 3 times the tube life, 1/3 the heat, a super wide frequency response of 8hz -60Khz, and a under 2 ohm output impedance to play nicely with all speakers, are all included. There is also a sophisticated speaker protection system to prevent damage to the amplifier and speakers if there ever was a tube issue.
Fern and Roby Audio designed the casework featuring front and rear panels milled from slabs of aluminum, Cardas RCAs, WBT copper binding posts, front panel industrial toggle switch, and a stereo mono switch with all markings laser engraved.
David Berning designed, hand-built by Linear Tube Audio, with casework by Fern and Roby.
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