Linear Tube Audio MicroZOTL MZ2 Review Page 2


The first thing I notice about this amplifier is that the perceived frequency response seems very even. There is a warmth and depth to the sound that I typically associate with tube amplifiers, but without the usually accompanying bloat or frequency colorations. It’s definitely still a tube amp, but there’s a real sense that the MZ2 isn’t fudging things quite as much as more traditional tube amps I’m used to. This has some benefits – namely that it works with a wide variety of music and the aforementioned frequency response is perceived as flatter. On the other hand, it won’t take the edge off an unmodded HD800 or headphones with forward treble.

Part of the clarity that the MZ2 exhibits is also in transient detail. A lot of all-tube amps either have an exaggerated leading-edge attack, or they soften transients. The MZ2 feels like it exists somewhere between a solid-state amp and a tube amp. I wouldn’t say it has the ‘best of both worlds’ but it seems to have a very crisp, tight attack that despite being very dynamic, never turns into fatiguing white noise, no matter how loud it was pushed. The MZ2’s transients also seemed to emerge from an auditory ‘space’ rather than being up front and in your face. What I mean by this is that the sound stage, something usually fairly weak in headphones, always seemed to be the source of transient energy, so that when the leading edge of an instrumental or vocal attack hit, the noise didn’t artificially jump out. This is behavior a lot of amplifiers can exhibit, where the sound stage degrades during sudden dynamic or transient contrasts, and the behavior usually worsens when turned up loud. I couldn’t reach a point where this behavior was exhibited by the MZ2 at any volume I could tolerate. Personally, I find this behavior very pleasing, though it’s certainly has a distinct ‘sound’ to it that I’ve not heard to this extent.

The transient behavior I noted above seemed to extend from bass to treble, and the amp certainly didn’t exhibit a surplus of treble ‘air’ that some tube amps do, nor did it push the midrange forward. There was a slight bloom in the bass, but I actually heard this more as a sense of harmonic richness rather than the all-out ‘bloomy’ saturation some pure tube amps exhibit. The bass behavior, despite this slight richness, is surprisingly tight. Almost par with a couple very good solid state amplifiers I have currently and it certainly isn’t boomy or lacking in perceived control. I suspect the ZOTL technology if measured, probably has a very good damping factor for a tube amp, as this sense of control extended to the remarkably clean midrange. Again, with tube amps, I’m used to hearing some saturation, peakiness and general coloration. Here, the amp was nearly on par with some tube hybrid and solid-state amps I compared it to – the midrange was clean, deep and detailed. Treble likewise was very clean, and while there may have been a tiny hint of sparkle or sweetness at 10Khz, I actually felt the treble was one of the least tube-sounding aspects of this amp. It wasn’t dry, it wasn’t bloomy, it was simply clear and dynamic.

I threw a pretty wide variety of headphones at it, from super power-hungry planars, to very sensitive high-impedance dynamics and everything in between. The amp handled all but the most power hungry planars extremely well. If you’re looking to power an HE-6 or other headphone that eats current for breakfast, you might be better served elsewhere. While the MZ2 didn’t sound anemic, nor did the sound seem to break up as it does with lesser amps, but high powered solid state amps simply had more to offer here. That said, I was able to drive current Mr. Speakers, mid-priced HifiMan and Audeze headphones all without feeling the amp was being pushed too hard. It holds up exceptionally well even to some of these fairly inefficient cans. Unusually, I didn’t feel it paired any better or worse with high-impedance dynamics than inefficient planars. All the headphones seemed to work equally well with the amp, and it gave me a similar sonic personality with all of them.

You may see this as an upside or a downside, though I think at the very least it supports LTA’s claims about the benefits of the ZOTL technology.

Personally, I find the mostly even tonality with a touch of richness to be really pleasing, it has a sweet sound on simple music, but retains plenty of clarity and detail on complex music. I’ll mention also that I tried the ZOTL as a preamp in a few hi-fi systems, as well as my recording studio setup. It performed admirably and had a mostly linear sound, as with headphones, but a more readily apparent warmth. The transient behavior was even more enhanced and the soundstage the MZ2 throws with speakers is positively huge, in a really pleasant way. Dynamics have a real heft and sense of scale to them, even on smaller speakers.


Linear Tube Audio has something quite special on their hands in my opinion. I tend to like tube amps that lean to the neutral and fast side of things, but I still appreciate the liveliness and richness they bring. There are only a few amps I’ve heard that pull this off, and the ZOTL is the newest member of that list. It is not the amp to pick if you’re looking to tame bright or harsh headphones, and I’ve heard tube amps that do the ‘airy’ treble and ‘holographic layering’ tricks better than this one. Where the MicroZOTL excels is in its truthfulness and its value for the money. The MZ2 isn’t cheap, but I feel that it represents an excellent piece of gear for the asking price, and it’s’ something I would contemplate purchasing if I were in the market for a tube amp at the price. It’s not a very nice tube amp for an attainable price: it’s a very nice tube amp at an attainable price that will drive just about anything in a comparable price range equally well. Finds like this are rare in the tube world, where parts can be expensive and engineering tradeoffs abound – everyone is looking for that sweetspot of performance and price, and generally, only time, testing and listening will tell. In the case of Linear Tube Audio’s MZ2 I think we have a real sweetspot product. Get your ears on this one if you’re in the market for a really balanced tube amp.

Linear Tube Audio

Simply Nobody's picture

May be inner/Fidelity could also review the new Manley Absolute tube headphone amp? :-) ........

Grover Neville's picture

I’ve actually got it right here and am in the process of reviewing it!