In our reviews we often describe the latest products of well-known brands, and so they are eye-catching devices, regardless of their functionality and price range. This time we decided to test something very rare - a tube headphone amplifier made in Greece. Although Lab12 is quite successful and presents its products at international exhibitions, the company is pretty much unknown in the audiophile world. On the web there were just a few coverages, and one review written by Matej Isak from the Mono and Stereo magazine with whom we collaborate. The company is situated in Athens, and beyond the home market its products are distributed in four European countries. They are Hungary, Norway, Switzerland and Poland. In the catalogue we find a power cord and five boxes for different uses - preamplifier, DAC, power amplifier, headphone amplifier and a passive preamp with source selector. All combine classic design and valves - even the DAC output stage is built around the tubes.
The company also announced three new models, but certainly it's not a giant, and probably will not be one over the next few years. However the described model has two enormous advantages that make it a hot item. Firstly - this is a very versatile headphone amplifier with built-in USB converter and preamp. Add a digital coaxial output and you will receive a device that can be a partner for headphones, active speakers and amplifiers or even act as USB-SPDIF converter. Secondly - the price. $1200 for a tube headphone amplifier combining so many features and handmade in Europe is a very reasonable offer, at least in theory. How will it work in real life?
Design and functionality
There are many things for which you can fall in love with this device almost immediately after unpacking. HPA is a very handy and well-made box. Reading about the manual production I had mixed feelings, because it all depends on the skill of the person who holds a screwdriver and solder. This can be noticed even in the way of cable assembly. Some plugs look like they were set up by an experienced jeweler, others bend, break and fall off after some time. Greek amplifier has been put together very well and it works infallibly. Housing parts fit together perfectly, sockets on the rear panel are arranged logically and conveniently, the potentiometer is running smoothly and rotates with a gentle, pleasant resistance. We have it all here - the elegant front finished with car lacquer, the meter with visible mechanical components backlit in green, convenient volume knob, a big headphone jack and valves glowing in orange inside the device. You can see the inspiration from Luxman and Dan D'Agostino amps, but I don't think anyone will complain about this.
When the power cord is connected, the LED labelled USB In should light up. This is because the HPA can work as a USB-SPDIF converter even when the rest of the circuits is turned off. People who use this feature can reduce energy bills and tube wear. When you press the main power switch on the back of the IEC socket, two more LEDs light up, the output power meter illuminates and the valves begin to heat up inside the enclosure. On the rear panel we can find the selector of headphones impedance, preamplifier output, digital coaxial output, two analogue inputs for external sources, USB type B and a rotary source selector. I have to admit that the transfer of this element to the back is quite unusual, and it may cause difficulty to owners of more complex systems. If you use only one input, generally there is no problem, but if you often switch to, for example, the USB port and one of the analogue inputs for listening to the CD player, turntable, receiver or streamer, you will have to to leave yourself some space to be able to reach the knob. If we put the amplifier on the desk, it will be easy, but it can be a nuisance in the tightly built-in cabinet. Perhaps the designers decided that placing the selector in the back is so beneficial because of the topology of the device that it's worth doing even at the expense of functionality. Or maybe they came to the conclusion that anyway the HPA should not work in tight crevices, because as a tube device it heats up and needs proper ventilation. Nonetheless, in the back we have also the selector of the headphones impedance. We can choose two modes - HI and LO, but the manufacturer must have forgotten to inform users about the division point. Or maybe we are just free to experiment and choose the best option for each of our headphones. Either way, choosing this device you have to remember to provide it with some air and leave yourself access to the rear panel.
Going back to the good news, the HPA is completely hassle-free to install and use. Even connecting it to the computer runs absolutely smoothly. The manufacturer recommends using a USB cable for audio applications, but beyond this guideline they don't mention a driver or compatibility with the operating systems. After plugging the USB cable, the computer should detect a new device and display a message about the successful installation of the drivers. I didn't even have to change the audio output device because it has been converted automatically. The maximum parameters supported by the built-in converter are 16 bits and 48 kHz. It could be better, but on the other hand, if you are not a computer geek, you will have fewer problems.
HPA is an OTL amplifier, so there is no output transformer. We have a simpler structure, which - in theory - should provide a high quality sound. OTL devices can be fickle, but Greek engineers ensure that the HPA will work with headphones with impedance from 32 to 600 ohms, which in practice allows you to connect almost all of the headsets available on the market. As for the finish, you can choose the front panel in natural aluminium as well as in several painted versions - white, black and orange. Cons? For those who plan to use the preamp in combination with a power amplifier or active speakers, the lack of a remote control may be a problem.
Theoretically the tube sound should be associated with something very specific, but audiophiles understand this concept very differently. For some it is a warm sound temperature and prominence of midrange, some point to the immersive space and delicate treble, and others love the tubes for a great microdynamics and realism that gives the feeling of close contact with music. No matter what criteria we choose, the HPA meets them all. Its performance is full of very specific elements which together create a natural and consistent sound. It would seem that a combination of proper tonal balance with a deep, full bass, reasonably heated midrange and clear highs is a rather difficult task, especially in this price range. Preamplifiers for tens of thousands dollars can combine opposites, but is it possible to get the same effect with inconspicuous and reasonably priced device, which in addition is made so beautifully and can replace several other devices in the audio system? To do this, you need to be not only a very talented designer, but also a pretty good businessman. The product must be imported from Greece, put on the shelf, and therefore the distributor and the dealer have to receive their profit margin. The Lab12 itself must pay taxes, electricity and phone bills, shipping fees and rent a property to exist. The manufacturer also wants to earn something after buying parts and paying employees. In my opinion, after deducting the cost of housing and packaging, a few hundred dollars was left for electronics. I'm sorry, but that's the brutal truth.
Now you understand why I was not expecting miracles. I was hoping to hear the good sound, maybe a little too insulated, but generally acceptable. Meanwhile, I got a full composition, very interesting and refined in every detail. HPA is not the best headphone amplifier in the world, but in this price range its performance totally outclasses the competition. For many audiophiles it will be the perfect blend of tube warmth and transistor dynamics, sound temperature and transparency, solidity and rhythm.
To properly check the tested amp and find in its performance some flaws, I made use of the whole arsenal of headphones and CDs that expose different types of shortcomings. I was not afraid of the effects of the amp's cooperation with headphones with detailed and slim performance, but I thought it might have been worse with opposite mates. I thought that with headphones such as B&W P5 or Jabra Revo the sound will be a bit boring, but it wasn't bad at all. The HPA has its own character, so personally I liked connecting it with a bit braver headsets like Denon AH-D340 and Beyerdynamic DT990 PRO. My guess is that excellent results could be obtained with Sennheiser HD600 or HD700, the top models by Beyerdynamic, Audio Technica and AKG. I am also positively surprised by the built-in DAC. Of course, if you want to achieve even better results, you can invest in a separate DAC. But it is not necessary to enjoy a truly great sound. Everything you need for a start are headphones, computer and a decent USB cable.
Build quality and technical parameters
The Lab12 HPA is a headphone amplifier with built-in DAC, working as a preamp with RCA output and coaxial digital output. The manufacturer used three 6N1P double triodes in OTL topology, which allowed to obtain the frequency response from 5 Hz to 100 kHz (-3 dB). The enclosure is made entirely of metal. The front wall is a thick piece of painted aluminium, while the rest is closed by two profiles made of steel. The entire electronic circuit was mounted on a separate circuit board, attached to the side rails. What's worth mentioning is a small power plant in the form of a transformer made by T.Giatras Transformers company based in Athens. The quality of components doesn't give the reason to gripe. The electronic schematic is rather well thought out and quite conventional. The logo on the tubes suggests that they were made by Voskhod company. All of them are mounted on ceramic bases, which leaves us some room for experiments. If you for some reason don't like the sound with standard valves, you can easily find and install other ones.
Asus Zenbook UX31A, Audioquest Cinnamon, Naim CD5 XS, Cardas Clear Light, Sennheiser Momentum On-Ear, Beyerdynamic DT990 PRO, Focal Spirit One, B&W P5, Jabra Revo, Denon Music Maniac AH-D340.
Greek amplifier looks great and is able to engage the listener for long hours. I was wondering what is the reason of this. The key to success is probably the fine combination of all those features that make the music the most interesting. The HPA does not reproduce the sound, it plays with all its passion. Of course you can say that the violin is always controlled by man, but I believe that someone has also put a lot of heart into constructing this device. The HPA has a soul and it can be heard clearly.
Analogue inputs: 2 x RCA
Digital output: Coaxial
Analogue output: pre-out
Frequency response: 5 Hz - 100 kHz (- 3 dB)
Headphone impedance: 32 - 600 Ω
Maximum power consumption: 65 W
Output impedance: 4 kΩ
Dimensions (H/W/D): 11/32/29 cm
Weight: 6 kg