Rotaxis Audio claims that the Rotaxis Core 64 DAC is “ a reimagining of what digital-to-analog conversion should be – pure, elegant, and inherently analog. Built with no feedback, no noise reduction, and no digital trickery, the Rotaxis DAC restores music with unrivaled clarity and timing accuracy. It’s not built for the sake of pretty graphs. It’s not another op-amp box with marketing hype. The Rotaxis DAC is a built-from-the-ground-up, timing-focused, passive resistive ladder DAC designed with one goal in mind: to reproduce music in time, not in code . ”
Most modern DACs rely on high-speed digital processing such as delta-sigma modulation, noise shaping or digital filters that manipulate the signal to achieve impressive measurement specifications. The Rotaxis DAC does none of this. Instead, it offers an original architecture:
1. PulseAxis Staircase Design
At the core is a true resistive ladder with 24-bit resolution. Each bit is represented by a series of precisely matched resistors (typically 64 per exponentially weighted bit) arranged in a ring configuration that Rotaxis Audio calls a PulseAxis array. This isn’t just a row of resistors on a board — they’re specially woven into rings to reduce EMI, thermal drift, and crosstalk. Each bit isn’t just statically triggered. It’s clock-accelerated at a base frequency of 11.2 MHz and a sub-frequency of around 100 MHz — each ladder is triggered in quarter-clock intervals grouped by current weight (most significant bits first), allowing each resistor to stabilize before activating the next. The result is completely clean transfer between voltage levels, with no aliasing, no pops, and no zero-crossing errors. The per-bit averaging effect surpasses the best laser-trimmed integrated circuits and approaches metrology level, and is scalable from an available future model with 32 levels per bit to 4 rings of 64 resistors per bit! The resistor rings are physically intertwined on the board and counter-rotate to eliminate radio interference.
2. Thermaphase Averaging
Instead of digital noise shaping, Rotaxis Audio uses a proprietary analog system called Thermaphase. Rings of 64 levels eliminate audible patterns, and everything left over goes into ultrasound, where it is filtered out by a four-pole RC filter.
3. GlitchLock Timing
Rather than relying on one large clock refresh cycle, the Rotaxis DAC breaks up the activity using a timing system called GlitchLock, dividing the refresh cycle into quarter-note pulses within the DAC and octal pulses between the two polar ladders. This ensures that the current never jumps or overlaps at bit boundaries, minimizing distortion and noise. The result is ultra-low distortion—without digital filtering or noise shaping.
4. Class A output with transformer isolation
No op amps. The Rotaxis DAC output stage is fully discrete, Class A, and connected to the output terminals via Lundahl transformers. This preserves phase, eliminates ground loops, and provides the instant dynamic response found in the best analog gear.
5. Modularity and upgradeability
The Core64 model in its base version offers:
– USB, SPDIF and I²S digital inputs
– galvanically isolated power supply (external unit only)
– no touch screens, no noise – just a small volume and sampling rate indicator
In the future , an external control and streaming unit will be available for the Rotaxis Core 64 DAC , connecting via I²S over HDMI, allowing Core64 owners to expand their system without replacing the main DAC.
