iBasso DX340 MAX Digital Audio Player

The iBasso DX340 MAX is the ultimate evolution of the DX340 music player. Its discrete 1-bit DAC grows from 128 to 160 PWM-DACs, more than eight times as many as other portable discrete DACs, and with a complete redesign of the circuit and wiring the whole device measures −122dB THD+N on an Audio Precision analyser, comparable with 1-bit desktop DACs costing around $13,000. The fully differential amplifier gives 1,300mW per channel into 32Ω on battery, or 2,250mW from the included 12V supply, all in an aerospace-grade titanium body.

FPGA-Master 3.0 and a dedicated DSP

More PWM-DACs demand much tighter clocking and scheduling. iBasso’s FPGA-Master 3.0, built on years of its own algorithms, has 7.5 times the logic units of version 2.0. As the main audio controller it requests audio straight from the SoC and runs it from two Accusilicon femtosecond oscillators (phase noise as low as −158dBc/Hz at 1kHz) on a single synchronised clock, for picosecond-level control of the DACs and minimal jitter. New algorithms let you add even harmonics for a sound closer to a tube amplifier, or odd harmonics for more passion and vitality.

Rather than simulating DSP functions in software on the SoC, which has to run a complex operating system and suffers in real-time performance and jitter, the MAX has a dedicated professional audio DSP with 192dB dynamic range and −174dB THD+N. It handles decoding, volume, a 7th-order FIR filter and native DSD encoding, and the FPGA controls all audio processing independently, keeping the SoC’s noise out of the sound. Each leg of the balanced DAC uses discrete 40× FIR PWM-DACs followed by an ultra-low-distortion third-order low-pass filter.

Four batteries, separate analogue and digital power

Four custom low-impedance lithium-polymer batteries, 3,200mAh each, support fast charging and discharging and last longer than ordinary cells. Two battery management circuits power the digital and analogue sections separately, keeping the headphone amplifier’s supply stable and isolating digital interference. The analogue pack is two batteries in series, 8.4V: compared with a single 4.35V cell it gives steadier voltage, stronger transient output, lower internal resistance and less loss.

Patented 12V DC power

Connect the included 12V adapter and the MAX bypasses its batteries, powering the headphone amplifier directly from the 12V supply: its operating voltage rises to ±12V and DC super-gain mode unlocks up to 2,250mW + 2,250mW into 32Ω. iBasso holds a national invention patent for this design. The DX320MAX could only run from its battery pack; the DX340 MAX offers both.

Cascaded current feedback amplifier

Compared with the AMP18 card, the MAX adds a differential buffer stage of two op-amps with up to 120dB common-mode rejection, for fully differential transmission that cuts noise from differing ground references and isolates the input from the power output stage. The four-channel, fully differential amplifier uses cascaded current feedback to avoid the delay of deep negative feedback, with 80 transistors in a two-stage design and a complementary output to reduce clipping. Output impedance is just 0.9Ω balanced and 0.4Ω single-ended.

Forty-eight nickel-chromium metal-film resistors sit at key points in the amplifier, tuned with many electrolytic and film capacitors, including legendary discontinued RIFA and Sprague parts. These take up so much board space that only the MAX version can fit them.

Analogue and digital volume

Separate analogue and digital volume controls allow more precise adjustment. The analogue control is iBasso’s custom 24-position stepped attenuator, built from 96 high-precision resistors, a tenth the size of a traditional one, with the channels matched within ±0.1dB. High digital volume keeps the full bit depth, while low analogue volume lowers the background noise, so iBasso recommends keeping the digital volume between 90 and 100 and setting the level with the analogue knob.

Android 13 and Mango OS

Android 13 on a Snapdragon 665 with 8GB of RAM runs streaming apps, with Android’s sample-rate conversion bypassed system-wide, so both the Mango Player app and streaming apps play without SRC. iBasso’s own Mango OS, built on Linux, is a separate, music-only system with optimised decoding and lower CPU load, and no Wi-Fi or Bluetooth for the purest, low-EMI playback.

Good to know

• The aerospace-grade titanium shell has dual volume knobs on the side and a back panel that comes off with two screws.
• In the box: USB-C cable, coaxial cable, burn-in cable, leather case, titanium cleaning cloth, 12V AC adapter, screen protectors, quick start guide and warranty card.
• See also the standard iBasso DX340 with its swappable amplifier cards.