Review: Linear Tube Audio MZ3

I just dropped the Linear Tube Audio (LTA) MZ3 at our local UPS store. It’s hot (112, says The Weather Channel), so I rushed back home to the shady, cool listening space that is my office. On the way back, I was thinking about the LTA amplifiers and the impact they’ve had on me. Every component I get quality time with and each review I work on simultaneously broadens my perspective on music and playback, while focusing my own preferences. It also has me thinking about why I listen to music, and why hifi is relevant. I don’t want to go on too long about why, when you are more interested in what the MZ3 is and how it sounds, but the more time I spend listening the more I believe that the why is as important here as anywhere else.

The Linear Tube Audio MZ amps and Zu Druid MKIV are a match made for the single(ended)-minded enthusiasts.

Reading virtual stacks of reviews, including those from adept and wise industry stalwarts, can only provide a guide for our own adventures and cannot replace experience. It’s a sign of our times that we often confuse information (often found online) with knowledge. I know it’s obvious, but bears repeating. Naturally, I’ve developed my own bias over the years. I find these are regularly dispelled by listening, and occasionally a component surprises. I am reminded of how little I know each time I review a remarkable component. My good fortune. For some time I’d imagined a clear path to sonic satisfaction. As it happens, the path is winding and perilous: Here be dragons!

On that note: The well known idiom, according to The Atlantic, is in fact, not printed on any known map. Apparently, there is just one globe— The Hunt-Lenox globe (c.1510)—that contains these words. Interesting.

image credit: Rare Book Division, The New York Public Library

You see I get off track, entranced by shiny (and other) things and the sonic sorcery of innovative audio engineering. Time and time again, I must remind myself to keep the music in focus. Hifi gives music its due. This came to mind when I read recent comments on hifi culture. I humbly submit (an outsider’s view) that the cultural disintegration some describe may be less about the cost of certain components (we all need to make money, and many things are quite expensive to make) and the strengths and weaknesses of certain formats (why wrap our identities around DSD, MP3, vinyl, or tape?), and more about how we perceive/value music, and, that the technology currently drives the culture. It seems today that technical progress is our primary goal. Acknowledging the importance of technical innovation, perhaps we as hifi citizens should consider another purpose alongside this one?

Now, back to it. I invest in hifi because I want to get as close to the music and the performance as playback will allow. The LTA MZ3 does this more effectively than any other amp I have spent quality time with.

Linear Tube Audio was founded by Mark Schneider in 2015. Their mission: to build components that bring exceptional realism and accuracy to playback. LTA opened with their update on David Berning’s original personal amplifier design, the MicroZOTL 2.0. Since that time, Schneider and Berning have collaborated on several amplifier designs.

In response to my request for additional comments on their products, he offered this:

If someone is new to LTA, they might look at our amps and think, “This is just another tube amp,” and not understand how very different and unique what we’re doing inside the amps is from any other amp manufacturer – indeed, it’s the only advance in tube technology since the 1960’s.

This fact in itself is sort of trivia to a consumer – you don’t need to know who David Berning is or understand ZOTL technology – but why we do things differently and the results of this different approach are very important: supreme realism and detail, 3D soundstage and imaging, and dead quiet backgrounds.

There are other non-sonic benefits to the way we operate the tubes as well: we run 1/3 of the current through the tubes than traditional tube amps, which means they run much cooler (no more running solid state in the summer because of the heat) and the tubes last much longer, think 10,000-20,000 hours vs the normal 1000-2000 hours.

The LTA MZ3 is a Class A push-pull amplifier that utilizes two amplification stages (12AT7 input tubes and 12SN7 power tubes) and no feedback. Of course, the patented David Berning ZOTL circuit is central to the design. There are jumper settings on the board allowing us to switch to 6SN7’s (the current choice for my own MZ2). My sample has 3 pair of RCA inputs, 2 pair of RCA outputs, and loudspeaker binding posts. We have many options here. On the face of it, we have a power button, input selector switch, volume control, digital display, output selector switch, and 6.5mm headphone jack. LTA offers a 2 year warranty and a 14-day no questions asked return policy.

The case, designed by Fern and Roby, is handsome, simple and very well built. No corners were cut. The chassis even feels good to hold. I think this may be the first amp I actually want to touch. I’m a Weirdo. Yes. Seriously though, you can feel it’s inert-ness. The amp is well-ventilated and gets warm to the touch. I have had some space-heaters here before. Not ideal for desert dwelling, but it was just a part of the experience. Now, I can truly appreciate a tube amp that sounds like this, and doesn’t get hot. The MZ3 maintains the desktop-friendly size of the MZ2, as well as their unique external power supplies. This is one benefit to removing the output transformers from the circuit.

I won’t load this review with more specs, and additional detail that’s already available regarding David Berning’s patented ZOTL circuits. Briefly, and at its most basic, the ZOTL circuit functions without the output transformers that the majority of classic tube amp circuits require. First, and somewhat like a radio transmitter and receiver, the audio signal rides a carrier signal, which is amplified by the tubes, then the carrier is dropped at the output. In place of output transformers, the ZOTL circuit utilizes impedance converters that handle the output and impedance matching for the amplifier/loudspeaker pairing. This allows LTA to avoid compromises to sonics that many output transformers present, and as I hear it, delivers more of the tube to listeners.

In response to my question regarding their preferred power tubes, Schneider replied:

If you can get Tung-sol 12SN7 Black Glass, these are the best tubes we’ve ever heard.

Because of the transparency of the ZOTL circuit, our amps are a platform for tube quality (and source quality). The better the tube the better the sound.

Since our amps are so quiet, they reveal any noisey tubes right away. For that reason and more, we source and supply only premium, fully tested tubes in our amps. This is an ongoing process that takes hours a week of testing, burn-in, more testing, and keeping everything organized. It’s worth it, though.

We use a number of different types of tubes across all our products. Because of the nature of the NOS tube supply chain, we’re not wed to one particular brand. We can’t be. But we have our own methods and secret suppliers that give us regular access to world-class tubes. I’ll leave it at that, but you’ll find the regular suspects among our tube collection: Amperex, Bugle Boys, Mullard, RCA, etc.’

A family portrait: the LTA MZ2 and MZ3

The MZ Comparison

Let’s say you, like me, own an MZ2—would I recommend an upgrade?

On a practical level, the new remote-controlled stepped attenuator and digital display will please the friends of convenience. The sleek chassis is certainly display-worthy. It does sound better than the MZ2. There’s a long list on LTA’s site, highlighting the upgrades that were made to the PSU, circuit boards, parts selection, chassis design, volume control, full function display and more. This is a huge leap in build quality—no detail overlooked. I’d call out the LPS+ cable with the locking XLR connector. Maybe not a top priority for buyers, which is why I bring it up; LTA and Fern&Roby left nothing out.

The MZ2’s original switching PSU next to the larger LPS+ for the MZ3

Before we get into my listening impressions, here’s another comment in response to my question about which styles of music are used when listening to LTA amps in development:

Well, the very first track played on our very first version of our very first amp was “Season of the Witch”…

One of the compliments we get is that our amps suit all sorts of music. I think this comes from the fact that we test our amps using all sorts of music. And since many of us are musicians, and those who aren’t are avid live music fans, we are very tuned into what real instruments sound like in real life. We are all about realism and trying to recreate the original performance in your room, so this certainly helps us fulfill that goal.


I think playback should be affecting. What’s the point, otherwise?

Music should not only get you dancing and thinking, but occasionally put the hurt on you; it can break you down and put you back together again. The Linear Tube Audio MZ3 in my system delivered the most engaging playback I have heard at home. This level of transparency to source could inspire hyperbole. My thought was that while listening to the MZ3 with the Aurorasound VIDA phono amplifier (also a very fine, musical and transparent amp) in the system, I could see into the grooves.

Thelonious Monks music for the soundtrack for Les Liaisons Dangereuses

The MZ3 delivers remarkable immediacy, convincingly real tone, dimension, speed and scale that bests every amp I have had here. It takes the talents of the MZ2 and strengths of the ZOTL circuit, and pushes them further. It is somehow quieter than the MZ2. I said in my review of the MZ2 that it was dead quiet, so this is impressive. I agree with LTA’s claims that the noise floor is lower, the image is larger, and the tonal integrity solidified.

Listening to dozens of records and streams, I experienced over and over again the ability the MZ3 has to remove most artifacts from the playback. Of course, this puts your sources in sharp focus. I trust the MZ3 would scale up for-ever…Kidding. Sort of. Though they do present a leaner (in comparison to my tube amps) sound, neither MZ amp goes anywhere near anemic. Maybe you dig a bit more bloom, in ah, your boom. I get that. My 45 DHT (the fantastic Toolshed Amps Euphoria 45) amp does blur things slightly in comparison to the MZ’s, and the AN UK OTO SE is decidedly more mid-forward and dense. Perhaps if your sources are lean and hungry (Gladiator?….anyone?), the MZ3 isn’t an ideal match? I’d still recommend a test.

the Bill Frisell Trio Live from 1991

In my system, voices and acoustic instruments are tantalizingly present, and well defined by their mass. Breath isn’t frosty, or carrying electric shards of high frequency hash. This is fine resolution, an abyssal noise floor and ultralinear performance creating a clean-room for you and your music. Not clinical, only devoid of those distracting playback artifacts. The amp will, given the right material, deliver a multi-dimensional image. Of course, through headphones this was even more apparent. Complex music was more clearly communicated. The low frequency performance (combined with the VIDA’s supreme low freqs) is just bananas: resolution, texture, control, and reach. This is a Head-Fi denizens desert island amp. No doubt.

At times, an idea I was reminded of recently came up: that loudspeakers are essentially microphones in reverse. Listening to Larry Grenadier’s The Gleaners record, I could imagine him standing there in front of the two mics (there’s a photo in the liner notes) with his bass. I could almost feel it. An instrument that large has Presence, and the MZ3 in my system was communicating a small bit of that energy to me.

The Zu Druid, Toolshed Amps Euphoria 45, and Aurorasound VIDA Prima

I know the one watt club has few members; there aren’t a lot of people who own loudspeakers with a sensitivity of 100db+.

I recently bought a pair of Zu Druid MKIV (101db – 12 ohm) from Zu Audio. I have had both the MZ2 and MZ3 driving them along with my 45 DHT amp, and the AN UK OTO SE integrated. LTA’s specs say we’re getting half a watt into 14 ohms. I know—crazy. My small, quiet listening space, which is roughly 10′ x 13′ x 9′, is ideal for low watt amps and sensitive loudspeakers. I was streaming modern recordings, in all styles of music and with louder recordings measured (cell phone SPL app, so take this for what it is) peaks of 91db+ from my listening position (approximately 7′ between the speakers as well as my seat) with the volume at 11:00. The scale and stability of the stage is impressive. It doesn’t hurt that the Druid are supremely dynamic, tonally virtuous, and freaky responsive. Combining this with the MZ3’s tonal balance, speed, dynamic range and bandwidth made for the most convincing playback I have experienced. Of course, more power does things the MZ3 cannot. Yes. Still, you may be surprised.

If you are a SET amp camp resident, then I recommend an audition. If you are a headphone enthusiast, you should join your SET friends in line. This is an amp you should hear.

Thanks for listening.

Linear Tube Audio MZ3
Price: $3700.00

System Details:

Clearaudio Concept TT (w/upgraded PSU and Satisfy black tonearm)
Aurorasound VIDA standard phono amp
Soundsmith Carmen MKII cartridge

Border Patrol DAC SE
Sonictransporter i5
Sonore microrendu

Zu Druid
Audioquest Nighthawk
Mr.Speakers Aeon closed
Fostex TH610

Luna Cables.