iBasso Nunchaku

The story of Nunchacku begins and perhaps ends at its dual Raytheon JAN6418 triodes. Placed at the voltage gain stage where they will yield the biggest sonic impact, the small output of these pentodes makes its presence heard on its 4.4mm balanced headphone out.

iBasso count on the square law function of Nunchacku's tubes to push down distortion at the drawing board. The huge operating voltages of this valve section in a device as small as this DAC/amp means that open-loop linearity exceeds virtually every other non-tube dongle or DAP ... at any price.

The signal that goes in, comes out amplified the same. You'll hear from Nunchacku the kind of effortlessness yielded only by high operating voltages and the non-existent capacitance of tubes. These factors allow minimum negative feedback to be applied, as what enters iBasso's JAN6418s has little error that needs correction.

The single-ended operation of Nunchacku's valves emphasises even-order harmonics for natural, engaging and warm sound. And the small quantity of tube feedback means distortion remains low order, rather than complex intermodulation.

iBasso's highly-linear small signal is then converted to balanced and flows into the player's differential solid-state output stage for muscle. These Texas Instrument op-amp buffers are the highly-fancied BUF634As of recent iBasso, Lotoo and Shanling Audio flagship fame – they'll do their job of supplying the grunt behind Nunchaku's delicate tube signal, guaranteed.

The hybrid combination of tube gain and solid-state power is a well-tried combination. And the BUF634As are ideal voltage sources and stable into capacitive loads, with their gain bandwidth product ensuring frequency response extends well beyond the human hearing range for excellent phase response and taut, impactful and life-like dynamics.

They promise high damping factor while maintaining its low distortion into low impedances typical of IEMs, Focals, Fostexs and Rosson Audio Designs, supplying over 1 watt of power in such cases!

Still the closed-loop internal gain remaining after the mandatory application of negative feedback around iBasso's analog circuit remains high, so Nunchaku can open up the sound of any high-impedance Audio-Technica, Sennheiser and ZMF Headphones.

In fact, give this triple wonder of Cirrus Logic, tube and BUF634A sound a go into any of your favourite transducers – the results will be surprising, never has it been done before. Check out how you can upgrade via iBasso's music players when you're done here, or view all our other DAC/amp dongles here.