The Chord Electronics Quartet upscaler represents the most significant advance in digital audio technology in the company’s history. Designed to overcome one of digital audio’s last great challenges, the subtle but crucial mistiming of transients, it brings listeners closer than ever to the realism, emotion and natural flow of live music.

At the heart of Quartet is the all-new Blackbird WTA (Watts Transient Aligned) filter. The culmination of 46 years of dedicated research by Rob Watts, Blackbird features an extraordinary four million filter taps, a tenfold increase over previous WTA designs. This remarkable achievement delivers a corresponding tenfold improvement in transient timing accuracy, revealing greater musical detail, depth and realism than ever before.

To process this unprecedented level of interpolation without compromise, Quartet employs five Xilinx FPGAs, delivering five times the processing power found in the reference-grade Chord Electronics DAVE DAC.

Nearly all of the filter’s mathematical coefficients approach the theoretical ideal sinc function, widely regarded as the benchmark for perfect waveform reconstruction. Just as importantly, all filtering is performed directly in hardware. By avoiding FFT-based convolution, a common industry shortcut that converts audio into frequency data and back again, introducing additional timing errors in the process, Quartet preserves signal integrity and delivers an astonishing level of transient precision and musical authenticity.

For the first time in a Chord Electronics upscaler, Quartet also incorporates a proprietary Pulse Array ADC. This innovative addition allows analogue sources, including high-performance turntables, to benefit from the same advanced upscaling technology as digital inputs. Its sophisticated decimation filtering virtually eliminates traditional aliasing distortion, setting a new benchmark that surpasses even many professional studio-grade converters.

A carefully engineered two-box architecture further elevates performance. By physically separating the sensitive audio circuitry from an independent Rob Watts-designed power supply, Quartet minimises unwanted interference and noise. The power supply itself incorporates a proprietary pinch-off RF filter, delivering a level of purity often associated with battery-powered systems while retaining the practicality of mains operation.

Around the rear, Quartet offers comprehensive, fully isolated connectivity, including USB-B, optical and dual BNC outputs supporting resolutions of up to 768 kHz. Fully compatible with all Chord Electronics DACs, and specifically engineered to complement the DAVE DAC, Quartet unlocks new levels of performance, transparency and musical engagement, bringing listeners even closer to the original recording.

The Chord Electronics Ensemble stand is available separately

Technical Specifications 

Digital inputs: 2x BNC (or dual BNC), 2x Optical, 1x USB-B (galvanically isolated)
Digital outputs: 1x Optical 192 kHz, 1x S/PDIF, 2x Dual BNC 768 kHz output
Analogue inputs: 2x RCA
Full Power consumption: 130 W
Standby power consumption: 20W
Upscaler DimensionsH x W x D (mm): 78 x 335 x 152
Power Supply DimensionsH x W x D (mm): 78 cm x 335 x 152
Weight: Upscaler 3 kg; Power Supply 3.2 kg