Here’s the beauty of the MZ2-S headphone amp.

It’s something all headphone amps share - but for some reason, it feels truly special with this one. You won’t notice it the first time you use it, but every subsequent time, you’ll find yourself waiting for it. Anticipating it.

It occurs before you start listening. You make sure the external power supply is on, that your cables are all connected, that your DAC is alive. You pick your music, and slide your headphones on. You hit the power button on the front of the MZ2-S, you turn the volume up…

And then you wait.

Not long. No more than thirty seconds. But in an age where so much music is available on demand, where gratification is instant, where we can have almost any audio experience we desire immediately, those thirty seconds are a lifetime. You have to wait for the tubes to warm up, you see. These are sensitive instruments, remember, and they won’t take kindly to Taylor Swift blasting through them before they’ve woken up.

At first, having to wait is surprising, almost irritating. But once you hear what this amp can do, once you’ve experienced it, it becomes the sweetest torture. There’s nothing wrong with having every song in the world instantly playable at your fingertips, but every so often, we need a something that reminds us of how good anticipation can be. The MZ2-S is that something. It’s expensive, and specialised, and not for everyone. But if you’re willing to give yourself over to it, you’ll be in for one of the greatest musical experiences a human being can have. 

Linear Tube Audio MZ2-S

Design

Let’s get into the details. Physical first.

Linear Tube Audio, the makers of the MZ2-S are a Washington, DC company who have been making phenomenal amps for a long time. Mark Schneider, their head honcho, began working with audio whiz Dave Berning in the 1980s, developing a technique in 1996 known as Zero-Hysteresis Output-Transformer-Less amplification (ZOTL). We don’t really want to go into exactly what this involves, mostly because we can see you drifting off already, but the upshot is that it’s informed the company’s products ever since, and has largely set them apart as an amp maker of superlative quality. They are best known for their MicroZOTL range, of which the MZ2-S is the latest version of.

The differences between this model and previous ones are largely internal, and start with the power supply, which has had a full makeover with an upgraded regulator. (Our review unit did not have this upgraded regulator installed, but we can certainly appreciate how it would make things different).

In addition, having an external power supply significantly reduces operational noise. That’s a big deal, especially when you’re dealing with sensitive electronics. We’ll touch on this a little bit more when we talk about the sound of the MZ2-S, but we can say that we never heard any audible noise coming out of this thing, even after long periods of operation, and at high volumes. It’s miraculous. That’s without talking about the heat it generates, or lack thereof, thanks to the low-current ZOTL circuit. After three hours of listening, it was still only mildly warm to touch. When you consider that most tube amps get uncomfortably hot after a while, that’s quite something.

The amp itself? It’s sweet. The front is unremarkable: volume knob, 6.3mm headphone port, nifty input selector. We did have some trouble with the power switch: it’s set flush with its housing, often leading to accidental half-presses. When the lone complaint you have about a unit is that its power button is fiddly, you know you’re dealing with something good.

Round the back, you’ve got two stereo inputs, and two always-on speaker outputs. The amp only puts out one watt of power, which is remarkable enough in itself, but it can quite comfortably drive any speaker over 90dB in sensitivity. We tested this, and it works like a charm.

The top is where the action is at. A clear plastic cover shows you the inner workings, including four gorgeous Russian Tung-Sol tubes. You may not be familiar with these, but take it from us: they are absolutely some of the finest around. Although they don’t have the overt glow of something like the Woo Audio WA7 Fireflies amp, they still emit a nice orange light when heated up. The cover is removable, and tube rolling (switching out existing tubes for ones you pick yourself, in order to customise the sound) is straightforward. We know this because when the unit arrived, one of the tubes was completely cracked. No fault on LTA’s part – they’d packed the unit carefully, and quickly sent out a replacement tube. You shouldn’t ever have to roll the tubes, which are of beautiful quality, but it’s nice to know that the option is there.

So it looks good, runs well, has a more-or-less idiot-proof design. But ultimately the question is this: what does it sound like?

Linear Tube Audio MZ2-S

Sound

Here’s the thing. We listen to a lot of audio equipment here at TMS. There’s a constant train of gear trundling in and out of our offices. But this is one of the few pieces of kit which we were actually sneaking off to listen to on the weekends, or late at night. The sheer joy of realising what it did to our music collection, having to wait for it to heat up, sliding on the headphones knowing - knowing - that we were going to hear something special, was just a revelation.

What does it sound like? It sounds like a gift from God. That’s what it bloody well sounds like.

For the most part, all tube amps sound good. Even those who obsess over solid-state amps will admit that there is something about these cylindrical pieces of glass that is just…different. And yet, we can comfortably say that not all of them sound like this one. It’s not just that we could hear every single element in the mix of whatever we listened to. It’s that every single one of those elements had an indescribable richness to them. No matter what we threw at it, it continued to treat each instrument like a precious, fragile jewel, something to be wrapped up in layers of soft velvet. It was glorious.

We know, we know. You’re supposed to be clinical and scientific when assessing an amp. But we’re not detail-obsessed audiophiles here. If you tell us that this amp is a Class A unit that uses radio frequency to change the voltage current transfer characteristics of the output tube, we will nod and smile, but we won’t actually be moved. But in the face of the sheer audio goodness this thing puts out, it’s difficult not to be. It’s almost impossible not to slip into hyperbole.

As we mentioned, briefly, when talking about the power unit, the noise floor is so low as to be effectively non-existent. And it worked on just about every headphone we used on it, and this being TMS, we had quite a few to pick from. At 2Ω output (1 watt at a 4Ω load) it’s capable of driving pretty much any dynamic and planar headphone. In the end, we settled for our Beyerdynamic DT 770 Pro (80Ω) cans as our default, mostly because they didn’t color the sound at all. Why would we want them to, when the MZ2-S is painting the music in just about every color of the rainbow?

Linear Tube Audio MZ2-S

 

Should You Buy It?

However, this kind of audio wizardry comes at a price. To get the MZ2-S, you’ll have to shell out $1845. That’s not including your headphones, which you’ll want to be decent, or your external DAC (we used the superlative Optoma uDAC5). That’s a lot of moolah, and not everybody will be able to afford it. That doesn’t make it overpriced; it’s worth every cent. But it’s not going to be for everyone.

Look at it this way. If you love your music, if you obsess over it, then an amp like this is an investment. What you’re buying here is not just a clunky black box. You’re buying a lifetime (or at least, ten to twenty years before the tubes need replacing) of those thirty seconds. The thirty seconds where you can find a good chair, pour yourself a drink, pick what you want to listen to, get comfy. You’re buying yourself an endless series of breaks from reality. You’re buying yourself the finest musical experience around.

Again, it’s hard to talk about the MZ2-S without sounding like we’re delivering a sales pitch. But outside of a fiddly power switch, it simply doesn’t have any weaknesses. It’s an almost perfect amp. And if you’re prepared to make the leap, it will be one of the best things you’ll buy.

See the Linear Tube Audio MZ2-S

Linear Tube Audio MZ2-S
 

Good:

Superlative sound and usability
 

Bad:

Annoying power button
 

Best For:

Investing in your music
 

Alternatives:

Woo Audio WA7 Fireflies

Without question one of the best-looking amps around. It’s slightly cheaper than the MZ2-S, and while it doesn’t offer sound that is quite a spectacular, it’s still a worthy alternative.

Fosgate Signature

While technically more hybrid than tube, audio designer Jim Fosgate’s baby is still one seriously impressive machine. The features include a surround sound mode, which gives the audio a more natural, immersive feel. It also looks terrific.

 

Breaking Down The Specs:

Amp Price Weight Dimensions Impedance Output THD*
Linear Tube Audio MZ2-S $1895 3.5lbs 9.5" x 8" x 5.75" 1W/4Ω 1%
Woo Audio WA7 Fireflies $1599 5.3lbs 5.1" x 4.8" x 4.8" 32Ω 1W/32Ω <0.03%
Fosgate Signature $1499 5lbs 11" x 7" x 5.5" 30Ω 1W/30Ω 1%

*THD = Total Harmonic Distortion

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