Note: All current production units include Cardas speaker binding posts and a pair of stereo subwoofer outputs, not shown in the photos above.

ZOTL Ultralinear+ Integrated Amplifier Overview

For those who demand the best, but want to keep things simple. The ZOTL Ultralinear+ Integrated amplifier delivers the magic, realism, and 3D soundstage of our patented ZOTL technology, all in one (gorgeous) package.

A single-component solution, the ZOTL Ultralinear+ Integrated amplifier incorporates the acclaimed ZOTL Ultralinear+ power amplifier, a Berning-designed preamplifier, and LTA’s digital control system–beautifully packaged in a Fern & Roby-designed case.

The ZOTL Ultralinear+ Integrated generates 20 watts per channel. This means it can easily drive speakers with sensitivity ratings at or above 88db for critical listening. For smaller rooms or non-critical listening, it can drive speakers rated down to 85db. In any configuration, listeners enjoy startling realism, plentiful bass, low noise, plus gorgeous mids and highs.

What’s New in the Plus+ Version

LTA is proud to announce the next generation, and first-ever upgrade, of the Ultralinear flagship amp. Introducing, the ZOTL Ultralinear+ Integrated Amplifier.

After trying over two dozen component combinations, and countless hours of listening tests and comparisons, the new ZOTL Ultralinear+ Integrated Amplifier 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.

Stereo subwoofer output has also been added. For those who prefer mono subwoofer output, that can be requested at no additional charge.

All new units ship with the Plus+ Upgrades installed. Existing ZOTL Ultralinear Integrated amp customers can get all these upgrades via our Ultralinear+ Integrated Amp Upgrade Program.

What’s Included in the New Plus+ Upgrades

1. 100,000µF of additional capacitor storage

2. Audio Note & Holco resistors

3. Subwoofer Output

4. Updated Volume Control w/ Adjustable Gain & “Hi-Res” Settings

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.

Reviews & Testimonials

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.

The Audio Beatnik Ultralinear Integrated Review

The Ultralinear Integrated’s sound starts with its ability to be both incredibly rich and nimble at the same time. The music flowed effortlessly into my room. The bass delivers real rhythm to the listener. It was very easy for me to feel like I was listening to live music. 

Tonal accuracy is the most important thing to me. Just as I discovered when I reviewed the Ultralinear Power Amplifier, the Integrated has amazing tonal accuracy. Instruments and voices simply came to life in the room when I was listening. 

This is an amplifier that pulls off a small miracle. It has such a big tone and at the same time, it is realistic. Yet the detail, speed, and micro-dynamics are not overdone. With the Integrated, my system seemed to introduce fewer distractions than I hear from most recorded music. This made it so much easier to be drawn into the music instead of listening to how my system sounds.

Enjoy The Music

I began to notice that the Ultralinear was capable of a degree of nuance and subtlety that was somewhat reminiscent of the Shindo Cortese when fitted with F2a power tubes instead of the 300B tubes it can otherwise employ. The F2a presentation is a bit less rich, weighty, and dense, but it is remarkably nuanced, subtle, and deferential which creates a kind of seductiveness that I found nearly impossible to resist. I found myself drawn to the Ultralinear in much the same way, or, I should say, for many of the same kinds of reasons. I would own a Cortese in a heartbeat if I could. I have no difficulty imagining settling in long term with the Ultralinear either.

New: Updated Volume Control w/ Adjustable Gain & “Hi-Res” Settings

Now shipping is our new 8-bit volume control, which gives you 128dB of total attenuation via 100 individual steps. We use precision thin film Nichrome resistors with low thermal noise and ceramic circuit boards with low dialectric constant for the highest level of clarity and transparency.

For the ultimate in control, you can activate the “Hi-Res” setting in the menu system, which offers 199 steps to dial in exactly the volume level that works best for you.

We’ve also added the ability to adjust the gain via the menu system. This adjusts the volume level to allow for finer low-level attenuation when using sensitive speakers or headphones. There are three settings: 0db (default), -15db, and -30dB.

Listening room sound. Living room simplicity.

Integrated with your life

We get it. You want the best sound you can get, but you don’t have the space, or desire, for separate components. With five inputs, LED display, brass touch buttons, home theater mode, and remote control, the ZOTL Ultralinear+ Integrated amplifier gives you world-class sound that fits into your life.

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 1.2 ohm output impedance means it plays nicely with all speakers.

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).

Patented perfection

The Ultralinear Integrated amplifier is based on David Berning’s patented ZOTL technology. For a technology to be patented, it must be deemed “new, useful, and non-obvious.” We think that sums up our approach quite nicely.

Looks as good as it sounds

The low-resonance aluminum chassis of the ZOTL Ultralinear+ Integrated is designed in Richmond, Virginia, by the award-winning industrial design crew at Fern & Roby. Brass touch buttons, LED display, and machined aluminum front and rear panels exude quality.

Premium components = premium sound

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.

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 hour range. Why? Because we use ⅓ the current through the tubes, which results in lower heat and dramatically longer tube life.

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+ Integrated amplifier is hand built by technicians with years of experience building the complex ZOTL circuits. All our products are backed by a 3-year warranty and a 14-day in-home audition policy.

ZOTL Ultralinear+ Integrated Amplifier 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, with all markings laser engraved.

David Berning designed, hand-built by Linear Tube Audio, with casework by Fern and Roby.  

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: 4 single-ended Cardas RCA stereo, 1 balanced input using two 3-pin XLRs

Speaker Output: 4 Cardas speaker binding posts

Headphone Outputs: Low: 300mW per channel @ 32 ohms, High: 2W per channel @ 32 ohms

Tape Monitor: 1 stereo tape monitor out, 1 stereo tape monitor in

Subwoofer Output: Stereo subwoofer output (Mono option available upon request)

Front Panel Controls: 7 brass touch switches (power, input, tape monitor, up, down, menu/select, back), volume control, and headphone speaker switch

Remote Control: All front panel functions using paired Apple TV Remote

Volume Control: 100 stepped attenuator (smallest step 1/1000th of total value) using Vishay Dale 1% precision resistors

Output impedance: 1.2 ohms

Input impedance: 47k

100V / 120V / 240V operation: Auto-switching

Hum and noise: 94dB below full output (measured at 20Hz-20kHz)

Power output with 8-ohm load: 20W, 0.5% THD

Frequency response (8-ohm load): 6Hz to 60kHz, +0, -.5dB

Amplifier class: Push-pull Class AB

Size: 17 inches wide, 5 1/8 inches tall, 18 inches deep (including connectors)

Net weight: Amplifier: 18 lbs./8.2 kg

Finish: Aluminum case

Tube complement: 2x 12AU7 preamp, 2x 12AX7, 2x 12AU7, 4x 17JN6

Home Theater Function can select any input for fixed volume

Display: 16 Levels of brightness and programmable 7-second time out

MM/MC Phono Stage: All settings configurable via front-panel digital menu system. See manual for more details.

Inputs: MM or MC
Preamp Gain (MM/MC): 34dB, 42dB, 54dB
SUT Gain (MC only): 20dB, 26dB
Resistive Loading (MC only):
20dB loading options (ohms): 20, 50, 75, 150, 200, 270, 300, 400, 470
26dB loading options (ohms): 20, 40, 50, 75, 90, 100, 120
MM loading: 47K ohms
Capacitive Loading: 100pF, 220pF, 320pF
Custom loading options are available. Please contact us prior to ordering if this is required.

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