Topping DX9 Discrete DAC
Digital audio specialist Topping has earned a global reputation for exemplary design and class-leading performance at accessible prices. With a range of DACs and amplifiers starting at £100 and stretching towards £2,000, the company’s products deliver exceptional value for money for both hi-fi systems and head-fi applications.
Topping’s latest premium-level device, the DX9 Discrete (£1,299) – a fully balanced DAC, preamp and headphone amp in a smart, compact chassis – is now shipping to the UK via Electromod. It stands apart from any other device on the market thanks to an array of proprietary technologies, including Topping’s ‘PSRM’ discrete 1-bit digital-to-analogue conversion architecture and ‘NFCA’ hybrid headphone amp circuitry. The result is a supremely versatile device delivering a remarkable sonic performance in a wide range of systems with headphones, speakers or both.
As well as having a clearly audible effect, this clever technology is also visible. The top of the DX9 Discrete’s chassis incorporates a tempered glass window that reveals the circuitry beneath like a panoramic sunroof. The glass is etched to highlight each section and the circuitry illuminated with a gentle orange glow – visually impressive and fascinating too!
Design and build
Solidly built and perfectly proportioned, the DX9 Discrete’s aluminium chassis measures 340x60x225mm (WxHxD) – small enough to fit comfortably on a desk, table or sideboard yet sufficiently large to ensure its impressive circuity isn’t compromised. A single multifunction rotary control sits centrally on the fascia, programmable for easy access to the functions its owner uses most often, flanked by a pair of crisp colour displays.
These 2-inch displays are highly configurable thanks to Topping’s Aurora UI, with nine colour schemes, adjustable brightness and more. Users can choose to show data such as incoming file format, sample rate and volume level, or select a ‘spectrum analyser’ (FFT) display – one for each channel – to represent the audio signal’s frequency components in real time. Another option displays classic VU-style meters, showing signal levels as the music plays and adding vintage appeal to this cutting-edge device.
The DX9 Discrete’s classy look and feel is further complemented by a neat remote control, housed in a unibody, CNC-machined, high-density aluminium chassis with a fine sand-blasted finish. Topping’s DACs span a variety of sizes and, most interestingly, technical designs. While most brands select an off-the-shelf DAC chip from a single supplier to build their devices around, Topping has engineered a collection of technologies to suit different applications, customer preferences and price points. At the lower price tiers, several high-spec DAC chips are used from leading suppliers ESS Technology and AKM, carefully selected and masterfully implemented. The range also includes an ‘R2R’ DAC, using a ladder-like network of resistors instead of chips to convert digital signals to analogue.
Several years ago, Topping began developing something completely different, specifically for its top-tier devices – a proprietary technology unlike anything seen in comparatively priced DACs. It’s not an R2R design, nor does it use third-party off-the-shelf DAC chips. Instead, it’s an innovative digital-to-analogue conversion technology with a discrete 1-bit architecture, designed and built entirely in-house – Topping calls this ‘PSRM’ (Precision Stream Reconstruction Matrix).
The DX9 Discrete represents the third iteration of Topping’s PSRM technology, following 2024’s D90 III Discrete and 2025’s D900. While the D900 – a pure DAC/preamp with no integrated headphone amp – is PSRM’s pinnacle with its 32-element architecture, the DX9 Discrete’s refined 16-element implementation delivers an outstanding technical and subjective performance that sets it apart from other DAC/headphone amps on the market.
More about PSRM DAC technology
When DAC circuitry is described as ‘discrete’ – using individual electronic components for the conversion process rather than an integrated chip-based solution – it’s usually assumed to be an R2R design. But PSRM is, essentially, a 1-bit delta-sigma DAC technology; while R2R uses a ladder of resistors to represent different bit values, PSRM uses a high-frequency 1-bit stream.
The process involves discrete 1-bit modules converting digital audio streams into analogue voltage by turning each audio sample into an ultra-fast train of 1-bit pulses. The density of this pulse train – the proportion of ‘ones’ versus ‘zeros’ – represents the instant waveform level; these pulses are then averaged/smoothed with an analogue reconstruction filter. While in essence this is a form of delta-sigma processing, the implementation, algorithms and circuit choices are unique to Topping.