Chord Electronics Debuts Quartet Upscaler

Posted by The Sound Organisation on May 22nd 2026

Nearly 8 years ago, Chord Electronics introduced the M Scaler, an ingenious piece of kit that upscaled digital audio files to something approaching the richness and depth of true master analog playback. It was hailed as "remarkable", "unparalleled", "transformative and profound" with over 1 million filter taps processed on a single FPGA circuit. Now comes the next generation of that technology, refined and improved over the past decade and upgraded to a reference-class product: The Chord Electronics Quartet.

The upgrades begin on the circuitry level, with the Quartet utilizing 5 FPGAs instead of 1. Additionally, Rob Watts has made substantial improvements to the Watts Transient Alignment filter. This new Blackbird WTA filter offers a tenfold improvement in timing accuracy and utilizes over 4 million taps. Chord Electronics has also integrated a new Pulse Array ADC that allows even analog sources to benefit from the upscaling capabilities of the Quartet. The Quartet enters the line-up under the Choral range, pairing perfectly with the the flagship Dave DAC along with the Etude Amplifer, Symphonic Phonostage, and Prima Preamplifier.

Here's what Chord Electronics has to say about the new Quartet:

The Quartet represents the most significant advancement in digital audio technology in Chord Electronics’ history. A reference-class digital upscaler, the Quarter addresses a fundamental flaw inherent in standard digital playback: the subtle but critical mistiming of transients.

At the core of the Quartet’s performance is the all-new Blackbird WTA (Watts Transient Aligned) filter. Representing the culmination of 46 years of specialised research, the Blackbird filter utilises a staggering four million filter ‘taps’—the technical measure of interpolation complexity. The Blackbird WTA represents a tenfold increase over previous WTA designs, achieving a tenfold improvement in transient timing accuracy, plus it has even more ‘taps’ at its disposal for even better performance. To process this complex interpolation algorithm without compromise, the Quartet utilises five (5x) Xilinx FPGAs, (five times the processing power of the reference DAVE DAC).

Technically, nearly 100 per cent of the filter’s mathematical coefficients reach the theoretical ideal ‘sinc function,’ in other words, the ‘gold standard’ for perfect waveform reconstruction. Crucially, all filtering is executed directly within the hardware architecture. By avoiding the software-industry shortcut of FFT convolution, which converts audio to frequency data and back, introducing further timing errors, the Quartet preserves pure signal integrity, delivering unmatched transient fidelity.

For the first time in a Chord Electronics upscaler, the Quartet integrates a proprietary Pulse Array ADC (analogue-to-digital converter). This allows analogue sources, including high-end turntables, to benefit directly from the device’s upscaling power. By employing advanced decimation filtering, the integrated ADC eliminates traditional aliasing distortion, outperforming even dedicated studio-grade conversion hardware.

To protect the digital signal from interference, the Quartet benefits from a two-box configuration. The sensitive audio circuitry is isolated from an independent, Rob-Watts-designed power supply that incorporates a proprietary pinch-off RF filter architecture, achieving the exceptional sonic purity of a battery-powered device from a mains-connected unit.

The rear panel features comprehensive, isolated connectivity, including USB-B, optical, and dual BNC outputs capable of supporting maximum resolution up to 768 kHz. The Quartet is compatible with all Chord Electronics DACs and is capable of unlocking the full potential of the DAVE DAC.

Chord Electronics teased the release of the Quartet at recent audio shows, notably making waves at the Bristol Hi-Fi Show as covered by John Darko and Jason Kennedy, and even back to the 2024 Munich High-End. But now the technology is perfected, and the attractive housing that fits within the Choral range has been released worldwide, with the first model due to arrive in the United States this summer. The Chord Electronics Quartet retails for $35,995 and will be available at select retailers. Click here to find a Chord Electronics Retailer near you.

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