iBasso DC-Tonfa 8 Channel R2R Dongle DAC

The iBasso DC-Tonfa is a portable USB DAC and headphone amplifier with a desktop-class R2R DAC inside: a discrete, 24-bit, eight-channel, fully balanced resistor-ladder design. It was developed jointly by iBasso and e☆earphone, one of Japan’s largest earphone and headphone specialists, who shaped its design, accessories and sound. With up to 800mW per channel from its 4.4mm output, NOS playback plus four digital filters, an OLED screen with a multifunction dial and a MagSafe-compatible case, it brings real R2R sound to your phone or computer.

Tuned by a specialist shop

e☆earphone, which has listened to what its customers want from their sound for many years, handled the product design, the accessories and the tuning, refining it through prototype after prototype. Its tuning lead, a long-time iBasso fan known as Yuudi, aimed for a sound you can simply surrender to: lively and spacious, with a natural, smooth texture, plenty of body and musical warmth, while keeping iBasso’s strengths in vocal texture and spatial presentation.

Eight-channel, fully balanced R2R

The DC-Tonfa uses a 24-bit, eight-channel R2R DAC built from discrete parts, in a balanced, fully differential architecture. Running R2R conversion through the whole balanced path reduces zero-crossing distortion and improves linearity at low levels, so it keeps the character of R2R while delivering fine detail, delicate expression, resolution and dynamics.

NOS plus four digital filters

Where most R2R DACs offer just oversampling (OS) and non-oversampling (NOS) modes, the DC-Tonfa pairs NOS with four digital filters of iBasso’s own design, based on its FPGA algorithms: LL/S, LL/F, Fast and Slow. You keep the distinctive R2R texture, with more freedom to tune the sound to your taste.

800mW + 800mW into 32Ω

The analogue stage is far bigger than a typical dongle’s: two high-performance Texas Instruments dual op-amps and four BUF634A buffers give up to 800mW per channel into 32Ω from the 4.4mm balanced output (5.2Vrms on high gain) and 219mW from the 3.5mm output, driving a wide range of earphones and headphones with ease.

An ultra-low-noise power supply

The DAC has its own regulated supply built around an Analog Devices LT3042 ultra-low-noise regulator, with just 0.8µV of output noise and 100dB of power-supply rejection, designed to be cleaner than the battery supply of many portable devices and to give the R2R DAC the stable power it needs.

Aluminium, glass and an OLED screen

The aluminium-alloy body is light and tough, with a 0.96-inch OLED screen and a multifunction dial for intuitive volume control and the main settings. An “R2R” engraving on the side and tempered-glass front and back panels carrying the iBasso and e☆earphone logos mark it out as a collaboration model. Choose calm black (a special colour picked by Yuudi), fresh blue or vivid red.

A MagSafe-compatible case

The supplied case, designed specially for the DC-Tonfa, attaches magnetically to a MagSafe phone or MagSafe case, holding the DAC firmly to the back of your phone. Its front is cut away so the screen and glass panel stay visible.

Apps, cables and compatibility

On Android, the iBasso UAC app shows and changes the digital filter, gain, channel balance and other settings; on Windows and macOS, iBasso’s browser control panel does the same with nothing to install. The USB-C cable is detachable, so you can choose the cable for each device. Switch between UAC 2.0 and UAC 1.0 for phones, computers and games consoles, and use the S/PDIF digital output to make it a digital source for a hi-fi system.

Good to know

• It has no battery and is powered by the phone or computer it is connected to.
• The iBasso UAC app is not available for iOS; iPhone users can change the main settings with the DC-Tonfa’s own screen and dial.
• In the box: DC-Tonfa, MagSafe-compatible case, USB-C to USB-C cable, USB-C to Lightning cable, USB-C to USB-A adapter, quick start guide and warranty card. Black, blue or red.