BALANCED AUDIO TECHNOLOGY REX digital-to-analogue converter
+ Superlative performance across the board; complete absence of any digital glare; will add colour and warmth to any solid-state system.
– In terms of sonics and tonality, nothing; noise floor not absolutely silent as normal for a tube-based design, but negligible once the music starts.
IT HAS been almost 37 years since digital audio playback was introduced to the consumer market with the launch of the Compact Disc back in 1982. In its relatively brief history, we’ve seen the birth and death of multiple physical formats (goodbye miniDisc, Digital Compact Cassette – and debatably, the CD itself?) and the progression to high-resolution formats and streaming delivery systems.
The technology has evolved so much since then and likewise, the quality of playback – yet, there remain significant numbers of detractors to digital audio. The critique most heard is that digital is cold and sterile, lacking an ability to warm the heart and make a connection to the human soul the way analogue formats can.
Whether there is any merit to these claims is debatable – but anyone would be hard-pressed to say the same if they listen to the REX digital-to-analogue converter (DAC) from Balanced Audio Technology (BAT).
Any product from the BAT stables with a REX label on it is not to be taken lightly. It signifies that this is the company’s top-of-the-line, no holds-barred product and represents the pinnacle of BAT’s engineering expertise. So, the REX DAC joins the REX II preamp and mono-block power amps on the BAT throne. It is also interesting to note that there is no REX phono stage… yet!
What makes the REX DAC so worthy of the crown? For starters, it does all the usual digital formats up to 24-bit/384kHz PCM and 4x DSD (11.2896MHz). At the very heart of its digital-to-analogue conversion process is not any ordinary chip, but a field-programmable gate array (FPGA) from AK Design.
What does AK stand for, you ask? Well, those are the initials of Andreas Koch, the main man behind the design and creation of the DSD format. If you want the digital decoding done right, who else to go to but the one who came up with the concept in the first place? (Kind of like listening to a recording of Sergei Rachmaninov playing his own piano concertos, eh?)
It doesn’t stop there. The REX is a fully-balanced dual-mono design and employs two large toroidal transformers in its power supply, backed up by a bank of massive custom-made capacitors.
The other thing you’ll see is that it employs six 6C19 triode tubes. These are rated at six watts each, which would actually be enough to power some high-sensitivity speakers. Using them in a line-level stage means they will be working way below any maximum operating demands.
Finally, instead of using direct or capacitor coupling in the output stage, BAT has decided to use amorphous core output transformers instead. The exact electrical science of why this is superior is complicated, but let’s just say transformer coupling is what is used in legendary and highly-regarded mixing consoles – the Neve, for example (do a search and you’ll see recording and mixing engineers raving about its superior sonics).
All this hardware takes up some serious real estate – the massive 14.5 x 48 x 39cm (h/w/d) unit weighs in at 14.5kg.
Setting up the REX is a snap. As it is a fully-balanced design, there are no single-ended outputs available and you have to use locking XLR plugs. Those who do not have XLR connectors can still use it with XLR-to-RCA converters, as I did.
It has six digital inputs – one USB, two Toslink optical, two S/PDIF electrical RCA and a single AES/EBU XLR.
Getting it to work with the Sony HAP-Z1ES HDD audio player was as simple as running a USB cable between the two units. With the Windows-based PC running jRiver Media centre, all you have to do is to download and install the drivers from the BAT website and select the relevant option on the media-playing software. For Mac users, it’s simply plug-and-play, of course.
As expected with a complement of six tubes, the REX does run hot, so ensure that it has sufficient ventilation; an air-conditioned room will also add to your personal comfort.
With all that in place, the only thing left to do is to let the music play and immerse yourself in the REX DAC’s marvellous sonics.
And simply glorious it is. It’s not about analysing in detail each and every aspect of its performance, it is the gestalt, the sum of its parts, the ability to draw you into the sonic landscape it paints that beguiles and keeps you listening hour after hour.
As a vinyl aficionado, my listening preference, admittedly, veers towards LP playback (fellow record lovers will understand what I mean). The physical aspect (i.e., the hands-on ritual when playing LPs) aside, there is nothing in the sound that makes me yearn for vinyl. The REX managed to imbue a warmth and a connection to the music that I have never ever experienced with digital playback.
Playing the same music on vinyl and high-resolution digital files was fundamentally different, of course, but provided valuable insights. LP playback tends to be harmonically rich, but the REX does deliver this in huge spades, Yes, it was of a different nature but it provided a similar musical feel – the sensation that you hare hearing more than just the notes the performer is relaying with his instrument or voice. Going out of the way somewhat here, but in some instances (the Doors and Led Zeppelin remasters, for example, where the source files are presumably the same) there was actually better low-end and treble extension as well as transients with the REX!
What really vowed me was listening to “inferior” CD-resolution 16-bit/44kHz playback. In every DAC I’ve used until the REX, there was always the feeling that there was “something missing” from the music, in addition to some graininess – particularly higher up the frequency range – that detracted me from complete immersion in the sound. This was almost completely negated when using the REX. Yes, there was a lower level of absolute resolution and the soundstage was a little flatter than with high-resolution files, but the resulting sonic retained the same musical allure and was never fatiguing. This gave new life to the entire library of rips from my CD collection!
Another outstanding aspect of the REX was how it painted a vast soundstage from everything I put through it – superior to anything I have heard in my system before. It wasn’t just about an increased breadth and solidity of the imaging, there was a tangibility to each individual instrument and voice within the mix that drove it home.
I attributed this to the REX’s ability to bring out the subtleties of the artistes’ performance – the rise in volume as bow pressure is increased across the strings or the crescendo in a the human voice as the singer goes through an emotive phrase. It was all so palpable that the overused phrase “sounds so real it was almost like a live performance in the room” applies here.
As the REX uses tubes, you should expect some low amount of tube noise. That said, it can’t be heard at normal listening volumes and you won’t notice anything once the music gets going anyway. I only noticed it when I pumped up the volume to see if I could hear it.
THE LAST WORD
Will the BAT REX DAC suit everyone’s taste then? I would say yes in a heartbeat. To be able to achieve such a high degree of analogue-like playback from any digital medium is truly something to be heard with your own ears.
The only possible situation where it may be “too much of a good thing” is when the rest of the system is already warm-sounding and employs tubes in multiple components along the chain – but then again, this may be exactly what the tube-loving crowd may actually want.
True, not everyone will be able to afford the REX DAC, but that’s the price one will have to pay for such a kingly performance.
Sources: Sony HAP-Z1ES HDD Audio Player, Toshiba notebook running Windows 10 and jRiver Media Centre; M2Tech Young DAC, Chord Mojo / Amplification: Odyssey Audio Tempest preamp, Odyssey Audio Kismet monoblocks / Speakers: Magnepan .7 / Cabling: DH Labs SilverSonic USB cable, Clear Day Double Shotgun speaker cables, an assortment of pure silver interconnects
Malaysian price: RM88,000
Malaysian distributor: Sapphire Audio Systems (+6016-220 5797) / Find your distributor.
Great review of the BAT REX DAC!
I am looking for a high-end streamer and DAC. My friends who are BAT enthusiast recommend BAT, but 3 dealers, of which 2 are BAT dealers, recommends the:
over the BAT
What are your thoughts?