Balanced Audio Technology REX DAC

What happens when you bring together two of the foremost designers in their respective fields to collaborate on one no-holds-barred product? In the case of combining the skills of Andreas Koch, one of the co-inventors of DSD, and Victor Khomenko, one of the world’s preeminent designers of output stages and power supplies, you get the world’s most musically natural sounding DAC.

Over the years we have experienced a number of attempts at curing hard digital sound. As good as some DACs are, many of us still prefer the sound of analog LPs. It would be unfair to say there is only one thing in the REX DAC that is a panacea, there is no single silver bullet, but digital can sound “analog-like” when every area of design is fully taken into account.

Features

Tube stage

The first thing you’ll probably notice is that it has tubes. Six 6C19 triode tubes in fact. These are the same tubes you’ll find in a BAT REX II preamp. They are extremely powerful (rated up to 6W each!), reliable and have wonderful sonic characteristics. This alone makes the REX DAC unique as one of the few DACs on the market with a real vacuum tube output stage.

The Andreas Koch FPGA DAC

The second thing you’ll notice is the AK Design DAC board. Andrea Koch has developed a custom FPGA based DAC using a proprietary algorithm, a physcoacoustic filter, that maintains the transient nature of a music signal without ringing or smearing. This filter has been developed through many years of research and experience, and has been custom tuned for the BAT REX DAC. Using this filter, all signals are converted to 128FS 1-bit Delta-Sigma, creating the most “analog-like” digital sound you’ve ever heard. And that is on ANY music you play, not just specially encoded types.

The Power Supply

We all know that a major factor in a components’ sound quality is the power supply. In that aspect, the REX DAC’s power supply would put most amplifiers to shame. It uses TWO large toroidal transformers and BAT’s custom made power supply caps. As you can imagine, the REX DAC has a big, powerful and effortless sound.

Amorphous Core Output Transformers

Take a look at those two non-descript black boxes near the tubes. Those are potted amorphous core output transformers. This is one area where Victor really took the gloves off. Most DACs are direct coupled or use capacitor coupled outputs. In developing the most recent series of BAT preamps, Victor discovered that transformer coupling yields far superior sound, with wider bandwidth and lower noise. It’s also much more reliable for long term use. The amorphous core transformers in the REX DAC are 10X more expensive than the standard transformers used in all of our preamps (except the REX II). They provide a natural yet detailed sound that simply draws you into the music.

Balanced Architecture and Zero Feedback

Core to BAT’s philosophy are balanced circuit designs with zero feedback. The REX DAC is no exception to that philosophy, it benefits from over twenty years of BAT developing some of the world’s best balanced amps and preamps.