The DX1 II uses an ESS ES9039Q2M DAC chip for digital-to-analog conversion. Compared with the previous DX1 generation, this platform enables higher dynamic range and lower distortion figures, which are reflected in both the line output and headphone amplifier measurements.

Low distortion affects signal purity, the intelligibility of micro-details, and the reduction of background noise. The 128 dB DNR indicates a wide dynamic headroom, helping reproduce the contrast between quiet and loud passages more accurately. The -140 dB crosstalk figure on the 4.4 mm balanced line output shows especially strong channel separation, which is also important for imaging and stereo positioning.

USB processing is handled by the 16-core XMOS XU-316 platform, which supports high-resolution playback up to PCM 384 kHz and DSD256 over USB. This digital processing platform provides stable USB audio operation with modern computer systems, working with a dedicated Thesycon USB driver under Windows and driverless operation on macOS.

The DX1 II USB input can operate in both UAC 1.0 and UAC 2.0 modes. UAC 2.0 is ideal for higher-resolution computer audio playback, while UAC 1.0 can provide compatibility with devices such as Nintendo Switch or PlayStation consoles. After switching modes, the USB cable must be disconnected and reconnected for the new setting to take effect.

One of the DX1 II’s key features is its high-precision 10-band parametric EQ. The PEQ can be adjusted by frequency, gain, and bandwidth, and it also supports separate settings for the left and right channels. This enables far more detailed tuning than a simple treble and bass control, as it allows targeted correction of specific frequency ranges.

PEQ operation is supported up to PCM 192 kHz / 32 bit. The function can be used through the headphone outputs, line outputs, and optical output, so the DX1 II can be integrated not only as a DAC or headphone amplifier, but also as a digital correction unit. The device can store up to three EQ profiles, which can be recalled manually or quickly via the C preset buttons on the remote control.

TOPPING Tune software provides detailed PEQ adjustment, including the import of target curves and raw measurement curves. The system can generate compensation from these data, allowing the character of headphones, speakers, or an entire system to be aligned more precisely with a desired tuning target. Multiple storable profiles are especially useful when the DX1 II is configured for different tasks, such as music listening, gaming, and movie watching.

The TOPPING Home Web platform offers a visual drag-and-drop PEQ interface. Community features allow users to apply EQ files, share their own profiles, and try other settings. Some platform functions will be introduced gradually in future updates, so their full availability should be verified.

The DX1 II features a dedicated optical input and optical output, supporting PCM 24 bit / 192 kHz and DSD64 DoP signal processing. This connection allows the device to function not only as a USB DAC connected to a computer, but also to receive digital signals from a TV, CD player, digital transport, streamer, or game console. From a galvanic isolation perspective, the optical path can also be a favorable choice in systems where separating the digital source from the audio components is important.

The optical output is especially useful when the DX1 II is used as a digital interface or DSP processor. A signal received via USB or optical input can be forwarded to an external DAC after PEQ processing. This allows an existing DAC or amplifier to remain in the system while adding the DX1 II’s 10-band parametric EQ functionality.

The DX1 II headphone amplifier section is built around a four-channel, fully balanced architecture. The independent left and right channel signal paths, extending from the DAC stage all the way to the output, support more precise control, stronger channel separation, and cleaner playback, especially when using the 4.4 mm balanced headphone output.

The device offers high-output headphone drive for headphones with different impedance ratings. The 4.4 mm balanced output can deliver up to 1000 mW x 2, while the 3.5 mm single-ended output also provides ample headroom for most headphones. As a result, the DX1 II works not only as a DAC, but also as a compact yet powerful desktop headphone amplifier.

The DX1 II’s two gain stages provide more flexible matching with different headphones and earphones. In Low Gain mode, the device offers finer volume control and a lower noise floor, which is especially beneficial with sensitive IEMs. In High Gain mode, greater drive headroom is available, allowing more demanding headphones to be controlled with greater confidence.

The device’s low noise floor and favorable output impedance support clean, stable playback from both the 3.5 mm and 4.4 mm headphone outputs. This allows the DX1 II to be used effectively with sensitive earphones as well as more serious headphones, while maintaining a quiet background and precise volume handling for everyday listening.

The DX1 II’s sonic character is built around clean, detailed, and stable playback. Low distortion, wide dynamic range, and a quiet background help music reach the headphones in a more natural, accurate, and less noisy form. The balanced amplifier architecture can be especially beneficial on the 4.4 mm output, where improved channel separation and more precise imaging may be achieved.

The bass range is controlled, the midrange is clean, and the treble is presented with an organized and detailed character. The device is not built around an exaggerated or forced tuning, but instead provides a precise foundation for shaping the sound to match the system and headphones. With the built-in PEQ, tonality can be customized in detail, so the DX1 II can be understood not only as a fixed sonic signature, but also as a flexible starting point for system tuning.

The DX1 II’s 3.5 mm headset connector supports TRRS gaming headsets with microphone input in addition to conventional headphones. The microphone input supports sampling up to 192 kHz / 24 bit, allowing the device to provide both playback and voice communication with a single headset. This design reduces dependence on motherboard audio solutions and provides a more consistent audio path for gaming, calls, or voice recording.

The 10-band PEQ can also play a role in gaming use. By targeting specific frequency ranges, separate profiles can be created to emphasize footsteps, environmental cues, or voice clarity, for example. In this form, the DX1 II is not simply a USB sound card, but a headphone hub equipped with configurable DSP.

In preamplifier mode, the DX1 II provides volume-controlled line output through both RCA and 4.4 mm balanced connections. This makes it possible to drive active speakers or a power amplifier directly from USB or optical input without using a separate preamplifier.

The balanced 4.4 mm line output offers a higher signal level and stronger technical foundation for systems where clean signal transfer, low noise, and strong channel separation are important. The RCA output is more practical for traditional hi-fi systems, while the 4.4 mm output can be advantageous with active speakers or amplifiers equipped with balanced inputs.

The DX1 II can be controlled with an infrared remote, which works without pairing or connection setup delay. The remote can switch between headphone, line output, and preamplifier output modes, as well as Low and High gain stages. Switching between the three EQ profiles is also directly accessible, providing quick operation when multiple usage settings are required.

The remote also supports switching between PCM filter modes. The eight filter modes are designed for fine-tuning digital filtering, so the device can be adjusted not only through software, but also through direct control. With the C preset buttons, PEQ, gain, and output mode settings can be recalled, simplifying switching between different system configurations.

The DX1 II’s USB-C connector serves as both a USB audio input and a 5 V power input. The device receives the power required for operation from a computer, tablet, or other compatible USB device, so a separate AC mains power supply is not part of its operating concept. The internal discrete low-noise reference power supply provides a separate and more stable power environment for the DAC and analog amplifier stages.

With tablets, compatibility may depend on the USB power delivery rules of the specific model. Some tablets may not provide sufficient or properly authorized USB power, so operation should be verified with such devices.