Who follows Alpha Audio a bit will probably already have read a review about the Dutch company Metrum Acoustics. And whoever comes here more often knows that we play at Alpha headquarters with the Pavane and the Ambre. It is therefore no secret that we have a bean for Metrum Acoustics. For your humble servant, the Onyx is the first introduction to Metrum Acoustics in your own set. The Onyx is a logical choice because we have been playing with Nos dac ourselves for years. Saying that we were curious about the results is therefore a serious understatement.
The name Onyx comes from a bicoloured mineral that is often used as jewelry. You can see the Metrum Acoustics Onyx as a hi-fi jewel, but one that doesn’t want to stand out. One who prefers to work discreetly. Who keeps himself in the background and lets the music speak for itself. A dac shouldn’t stand out in the set either. He must be invisible. Set and forget as the English say.
What is it?
The Metrum Acoustics Onyx is a so-called NOS dac. That means the Onyx is not upsampling or oversampling the signal. And that no filter is used in the output. In addition, the Onyx uses a ladder principle. Metrum works with in-house manufactured Transistor chips – now second generation – to convert the digital signal in ladder form to analogue.
On the Transient chips there is also an fpga which processes the incoming digital signal in two and divides it over the two internal dacs (there are actually two dacs in one module). Under the hood of the Onyx are four of these Transistor modules. So, in fact, eight dacs. By using only the upper registers of the dac, a lower noise floor and better linearity is achieved. At the output, the two signals are merged again. Metrum also uses this technology in the Adagio, Jade and for example Pavane.
Finally, the Onyx is a dual-mono dac. This principle ensures that the separation of both channels is very high (>120db) so that instruments can be positioned perfectly.
The Metrum Acoustics Onyx has 4 inputs as standard. USB, coaxial, optical and AES/EBU. However, as with the Jade, you can replace the USB module with an I2s connection to control an Ambre via Ethernet, for example. We play balanced via the AES/EBU connection because this gives the best results with our NADM50. At the back we find both single-ended and balanced outputs.
At the front all connections are neatly lined up and with the very fine, but minimalist, remote control you quickly go from one input to another. A blue light indicates which input is in use. The cabinet is neatly made but rather sober in appearance. In addition to our black version there is also a silver version available.