LTA ZOTL Ultralinear+ Power Amplifier Review

This post is not so much a review as it is an update on the differences between two amplifiers from Linear Tube Audio (LTA), the ZOTL Ultralinear+ Amplifier, and the original LTA ZOTL Ultralinear. I will also share the differences I heard between the two amps in my current reference system. I’ll start with a little bit about LTA including information about the ZOTL Ultralinear+ from their website.

Mark Schneider founded LTA in 2015 to manufacture David Berning’s designs.  An exciting thing about the ZOTL Ultralinear amp is that David designed it 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 Berning 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. It also delivers a big dose of realism.

Both the ZOTL Ultralinear and the ZOTL Ultralinear+ use Berning’s advanced and proprietary switching power supply optimized for audio. They also have all of the benefits of ZOTL technology. These include three times the tube life, one-third the heat, a super-wide frequency response of 8hz-60Khz, and an under 2-ohm output impedance to play nicely with all speakers. Both also have a sophisticated speaker protection system to prevent damage to the amplifier and your speakers, if there is ever a tube issue.

What’s Different with the ZOTL Ultralinear+?

On the LTA website they say:

“After trying over two dozen component combinations, and countless hours of listening tests and comparisons, the new ZOTL Ultralinear Plus 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 high-end non-magnetic Audio Note Tantalum and Holco Metal Film resistors, each type and value specifically chosen for each location.”

As I was listening and making notes to review the ZOTL Ultralinear+, my immediate reaction was that while I heard a difference between the two amps, it was not a big difference. In fact, the difference between the Ultralinear and the Ultralinear+ was not as much as I heard comparing the original microZOTL Preamp and the microZOTL Preamp Level 2 that I just reviewed (by the way, this difference was so significant that I purchased the Level 2 preamp).

Then it dawned on me that it has been almost five years since I listened to the original ZOTL Ultralinear amp. Plus, I didn’t listen to it in my current reference system. To review the two preamplifiers, I simply swapped out my LTA microZOTL Preamp with the Level 2. I didn’t make any other changes to my system. This made it very easy to hear any differences.

Since I no longer had a ZOTL Ultralinear amp in my system, I asked myself what I could do to get a fair comparison between the ZOTL Ultralinear amp and the ZOTL Ultralinear+. I remembered that my friend Ken Askew owned this power amp. So, I made arrangements for him to bring it over so that I could listen to it. This helped considerably.

After listening to both, I will stand by my statement. There are not as many differences between the two amps as there are between the two preamps. However, the differences are very significant and very easy to hear.

Comparing the Ultralinear+ to the Original Ultralinear

In my review of the original ZOTL Ultralinear amp, I said, “…the Ultralinear has the ability to be incredibly rich and nimble at the save 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. 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.”

Every word of this description is as true for the ZOTL Ultralinear+ edition as it was in for the original. Additionally, the ZOTL Ultralinear+ has deeper and more powerful bass. The ability to hear the air in and around a standup bass or a big bass drum is as realistic as I have ever heard.

This new version of the amp also has all of the rich tones that one could ever want from their music system. It is still able to carry the pace and rhythm of the performance in a way that lets you experience much of the joy of live music. The ZOTL Ultralinear+ also has a slightly faster and prettier top end. I could easily hear this when I listened to cymbals and bluegrass instruments.

No Amp is Perfect

Of course, no amp is perfect, and this includes the ZOTL Ultralinear+. However, when I listened to it on its own it seemed nearly perfect. The First Watt Sit-3 is an amp with similar power at about the same price.  Compared to the ZOTL Ultralinear+, the Sit-3 has a prettier sound overall, but it is much less powerful. It lacks the rich tones and deep bass of the ZOTL Ultralinear+. I think it would be safe to say the SIT-3 has a mid-range and top-end that is sweeter and prettier than the real thing. I found it very difficult when switching between these two amps to know which one drew me more into the music emotionally.

However, there is an easy answer to this quandary. You can buy a pair of Butler Audio MONAD 100-watt monoblocks and get the best of both worlds plus considerably more power. The only problem with this solution is that the MONADs cost $20,000 or roughly three times what the ZOTL Ultralinear+ costs.


If you don’t know by now, I love the ZOTL Ultralinear+ and I highly recommend it. Without a doubt, it is the best Class AB tube amp that I’ve heard in my room.

It’s a simple decision at its price point. LTA is pricing it the same as their original ZOTL Ultralinear amp, $6,800. If you own the original amp, the question is whether or not it’s worth $1,500 for you to upgrade it to a ZOTL Ultralinear+. Based on the time I spent listening to both amps, I think the answer is an easy yes.

Linear Tube Audio

ZOTL Ultralinear+ Power Amplifier – MSRP: $6,800

1 thought on “LTA ZOTL Ultralinear+ Power Amplifier Review”

  1. Thanks for the follow up! Glad you got to hear them side by side. As a Beta tester for the Plus upgrades I did the same. I agree with your listening impressions but would add a subtle but important sonic improvement. The UL + is slightly more full bodied sounding through the upper bass region. While the original was excellent in this regard the UL + renders strings and horns with a bit more texture that is closer to the real deal. In its current guise the amp is completely addictive!

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