iBasso DX270 R2R Ultra Digital Audio Player

The iBasso DX270 is a reference digital audio player built around “R2R Ultra”, iBasso’s deep reconstruction of the resistor-ladder DAC. A hybrid of 20-bit R2R and a 4-bit string DAC, in an eight-channel, fully differential discrete design with 344 precision resistors, is controlled by iBasso’s FPGA-Master 3.0 and a hardware resistor compensation network. The result is 130dB of dynamic range and THD+N better than −97dB, overcoming the zero-crossing distortion common to R2R designs with almost perfect linearity. Around it are non-SRC Android 13 and the Linux-based Mango OS, a Snapdragon 665, 4.4mm and 3.5mm headphone outputs, a 4.4mm line out, and a 12V input that unlocks up to 1,575mW per channel.

Eight-channel, fully differential R2R

The DX270 is fully balanced, with L+, L−, R+ and R− each containing two R2R DACs: an “8-channel R2R” layout. This differential design with dual DACs is the key to solving zero-crossing distortion. Where a signal passes through zero between positive and negative voltages, traditional single-channel decoding can leave gaps; the differential output of the two DACs fills them for smoother transitions, keeping the DAC linear even with small signals and pushing R2R dynamic range to an industry-leading 130dB.

20-bit R2R plus a 4-bit string DAC

For the most significant bits, the DX270 uses a string DAC, which approximates the target voltage directly through series resistors and switches. It gives a large dynamic range, low spurious energy and excellent THD+N, at the cost of needing more resistors, so iBasso invested heavily: 344 high-precision resistors in total, nearly double the count of a standard R2R DAC, for a more delicate, natural and pure sound.

FPGA-Master 3.0

Based on years of iBasso’s algorithm development, FPGA-Master 3.0 has 7.5 times the logic of version 2.0. As the main audio controller it fetches data directly from the processor, using synchronised system clocks with two ultra-low-noise Accusilicon femtosecond oscillators. It is also the “hardware calibration master”, detecting and compensating for component errors in real time, reducing their non-linearity and sharpening the precision of the resistor compensation network, which further optimises THD+N and dynamic range. It also gives you a NOS (non-oversampling) mode and four digital filters: fast roll-off, slow roll-off, low-latency fast roll-off and low-latency slow roll-off.

A hardware resistor compensation network

Alongside the FPGA’s algorithms, a compensation network of 76 very precise resistors improves decoding accuracy, extends the dynamic range and reduces distortion. This software-plus-hardware approach takes the R2R Ultra DAC past traditional performance ceilings: the equivalent resistance is accurate to 1.4 parts in 100,000.

Zero-crossing distortion, solved

Near zero signal level, zero-crossing distortion causes a loss of detail, unwanted noise or muddy bass, a common problem in traditional R2R DACs. With its fully differential design and precise calibration, the DX270 takes zero-crossing distortion down to −120dB, so subtle harmonics of instruments and the nuances of a voice come through clearly.

Outstanding linearity

Music’s complex waveforms are made of many frequencies, and if a DAC’s output is not perfectly linear it adds harmonic distortion, intermodulation and waveform distortion. With very closely matched resistors, precise switches and an optimised circuit, the DX270 goes beyond mainstream R2R linearity: iBasso’s measurements show it still linear at −120dBFS, and a dynamic range of 130.3dB and 130.1dB (AES17) on the two channels. The result is a “night-black” background and a natural, realistic presentation.

Two JRC analogue volume chips

Volume is controlled in the analogue domain by two dual-channel JRC volume chips, four channels in all. At low volume they attenuate noise along with the music, so at a typical listening level (50mV) the DX270 still achieves over 91dB SINAD for a clean, natural sound.

12V DC input and Super Gain

On battery, the balanced output gives 1,050mW per channel into 32Ω. Connect the supplied 12V adapter and the amplifier’s supply rises from ±8V to ±12V, unlocking Super Gain mode with up to 1,575mW + 1,575mW into 32Ω, enough to handle complex music and all kinds of headphones with ease.

Non-SRC Android 13 and Linux-based Mango OS

Android 13 has a refined interface and runs your streaming apps, and it bypasses sample-rate conversion at the system level so apps such as Mango Player work at their best. Switch to Mango OS, iBasso’s Linux-based music system, for dedicated playback with many advanced algorithms: lower processor load, no Wi-Fi or Bluetooth interference and lower EMI make for a purer sound. A Snapdragon 665 with 4GB RAM and 128GB of fast UFS 2.1 storage keeps everything smooth, a microSD slot takes cards of up to 2TB, and the 5.5-inch 1080 × 2160 screen gives rich colours and precise touch.

Outputs and USB DAC

A 4.4mm balanced and a 3.5mm single-ended phone output handle both balanced and single-ended headphones and IEMs, and the 4.4mm balanced line out feeds an external amplifier. The 3.5mm coaxial output sends a digital signal up to 384kHz, and in USB DAC mode the DX270 becomes a high-end, low-latency R2R USB DAC for a computer or smartphone.

Good to know

• Play time varies with gain, file resolution, volume and the headphones you use.
• In the box: DX270, leather protective case, USB-C cable, coaxial cable, burn-in cable, 12V AC adapter, screen protector, warranty card and quick start guide.
• Available in silver or grey.