iBasso Nunchaku Portable DAC and Tube Amplifier

The iBasso Nunchaku is a balanced portable DAC and headphone amplifier based on two CS43198 chips coupled to an FPGA to handle signal conversion up to 32bit PCM and DSD512. As for the amplification stage, you can choose between operation using power tubes for a warm sound or a more traditional Class AB operation for a more neutral sound with improved dynamics. The Nunchaku has an output power of 2x525mW at 32Ω, which is more than enough to drive any earphones and most headphones on the market.

iBasso Nunchaku: Raytheon power tubes

The Nunchaku uses two Raytheon JAN6418 power tubes, renowned for their compact size, low power consumption and operating stability. Unlike most portable products that use 9V or 12V power supplies, the Nunchaku uses a 22.5V anode power supply specially designed for the JAN6418 tubes. This higher voltage provides furthermore flexibility, ensuring that the tubes operate at their full potential. The two JAN6418 tubes give the Nunchaku a distinctive analogue sound, with a warm, relaxed and smooth tone that's a pleasure to listen to.

iBasso Nunchaku: Class AB mode

Furthermore, in addition to the TUBE output mode, the Nunchaku also features a Class AB amplifier circuit, allowing users to switch between these two output modes to enjoy two distinct sound profiles. In TUBE mode, the sound is soft and warm, with the characteristic timbre of this technology. Class AB mode, on the other hand, offers a more neutral tone as well as greater resolution and improved dynamics.

iBasso Nunchaku: 2x525mW amplification

Instead of an all-in-one amplifier chip, the Nunchaku uses a set of 2 OPAs and 4 BUF634A buffers from Texas Instruments for a total output power of 525mW+525mW at 32Ω, enabling it to drive all earphones and a good proportion of headphones on the market. Furthermore, this structure provides excellent efficiency with power consumption not exceeding 120mA/5V in TUBE mode and 100mA/5V in Class AB mode.

iBasso Nunchaku: Dual DAC CS43198

The Nunchaku's conversion stage is no slouch either, using two top-of-the-range CS43198 chips from Cirrus Logic, which, when coupled with the FPGA developed in-house by iBasso, enable conversion of a signal up to 32bit 768kHz PCM and DSD512, all in a symmetrical architecture.

Furthermore, the Nunchaku is equipped with a Femtosecond clock developed by iBasso, guaranteeing perfect signal synchronisation.

iBasso Nunchaku: JRC volume control

The Nunchaku's TUBE mode also incorporates a hardware JRC volume control, allowing the DACs to operate at their maximum output levels in order to give the tubes the most powerful signal possible to amplify. It is this amplified signal that is then lowered, reducing the background noise at the same time, resulting in a drastic improvement in the signal-to-noise ratio (SNR).

iBasso Nunchaku: PORON Suspension

In order to greatly reduce the impact that movements of the device could have on sound reproduction in TUBE mode, iBasso has fitted the Nunchaku with a suspension based on PORON material, which effectively absorbs shocks. The tubes protected in this way are much less sensitive to movement and shocks, ensuring quality reproduction, even when you're on the move.