Hardware Reviews



Quantization Noise Killed The Cat, an odd name for a DAC but this is no ordinary converter. Made in Norway for both the music lover and the hands on audio enthusiast the AB-1.2 is an asynchronous USB DAC in a compact box with a micro USB connector, RCA phono outputs and a light on the front. There are two switches on the back but they do not need to be used. The angle is that it’s totally open source, it has been built by enthusiasts for enthusiasts but is equally useful to music lovers because it’s pretty much plug and play. Unless you have a Windows machine and then you will need a driver as is pretty much always the case where Class 2 audio (sample rates over 96kHz) is concerned.

It is small and inexpensive, $170 or about £110 including shipping. It support all the usual sample rates up to 192kHz and runs an AKM4330 DAC chip. The box is much as you’d expect at the price, lightweight but equal to the task unless you hook up chunky interconnects in which case it will fall off the shelf, but that is easily remedied with some sticky feet or a cat, a small heavy cat that is.

What’s interesting is that it’s a modular device and if you are so inclined it’s possible to add a better power supply, alternative analogue stage or even a serious case. The USB 2.0 mini-B connection is a little inconvenient because you can’t get decent cables with it on, but you will probably have such a cable in the house already as it’s a popular size. I found one on my camera cable. Its makers advise against cables longer than 3m, which is generally a good idea with USB audio.


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My listening was with a Macbook Air running JRIver MC19 and first impressions were positive, it has poise, something that you have to pay quite a lot to achieve with CD and not a common quality with computer audio. Especially at the affordable end of the scale, next to a Cambridge Audio Dacmagic Plus which is a rather better made and equipped device it sounds quite forthright and shiny. This may be because you can’t exactly leave the QNKTC on to warm up in the way you can with a mains powered device. Taken on its own merit it delivers a highly coherent sound with strong imaging. Drums are well served, the natural acoustic around them making for particularly vivid stereo solidity. This coupled with a good grasp of pace means that you can overlook the slight forwardness.

In many respects reviewing this DAC in the context of a high resolution system is hardly realistic, but it does many of the things that high end DACs do, so it’s hardly out of its depth. The QNKTC looks like it should be a headphone amp/DAC, that is nearly always the case with compact converters these days, but the presence of RCA outputs means that you can use cables of the quality that will reveal its potential. And being an open source device it can’t be impossible to convert it to headphone driving operation.

This is a transparent enough converter to reveal nuances in the source material, I have a selection of vinyl to DSD recordings which JRiver in turn translates into PCM so that this DAC can play them. The vinyl transfer sounded sweet but the CD rip of ostensibly the same record (mastering tends to vary with format and vintage) had far nicer bass, phatter, juicier and with better leading edge definition across the band. Bass has always been a digital strongpoint of course, we love vinyl for its silky treble and open midband. With more up to date recordings this DAC extracts plenty of space and subtlety, the snare on Down in the Hole (John Campbell) has distinct reverb and the pace real drive. In fact everything played revealed its three dimensionality.


Out of interest I also contrasted it with a more expensive converter in the form of the Rega DAC, this has a drier balance but rather more power to engage thanks to first class timing. The Rega however is only good up to 96kHz so less ready for the high res revolution that seems to be gathering pace. The QNKTC put in a sweeter, richer performance with greater image scale. It has the sort of presentation that one associates with high end converters, whereas the Rega specialises in making you listen to the notes and the phrasing. The QNKTC will appeal to those looking for great imaging, it resolves low level detail uncannily well and makes all manner of recordings sound good. Laura Marling’s Little Love Caster is heart rending in its hands, but it’s a great tune.

I like the way that this DAC delivers such high sound quality for the money in a package that has the option of being upgraded by the end user. One suspects that its makers might regret encouraging this sort of behaviour, you can imagine how much support it could require, but it’s true to the spirit of audio adventure. And for that I salute them.

Update: since this review was published the QNKTC has become the Henry Audio USB DAC 128, this is the same product with an easier name and a different front plate.


Asynchronous USB Audio powered by Golledge high-quality crystal oscillators at 22.5792 and 24.576MHz
Supports the common sample rates of 44.1, 48, 88.2, 96, 176.4 and 192ksps
RCA (phono) stereo outputs
Asahi Kasei AKM4430 DAC
Atmel AVR32 general-purpose MCU programmed in open source C
ASIO driver for Windows programmed in open source C
Low-noise 3.3V LDOs powered from USB
The AB-1.2 is modular. An USB-I2S Module is plugged into an Analog Board.
Option of experimenting with power supply.
Lots of internal headers for experimenting.
Size Hx W x D: 32 x 114 x 120mm
Weight: 306 grams


Price when tested:
$170 including delivery
Manufacturer Details:

Henry Audio




Jason Kennedy

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