The FiiO K11 R2R is an ultra-compact desktop-class USB DAC and headphone amplifier. Instead of a typical delta-sigma DAC chip, it uses a custom-designed resistor-to-resistor ladder DAC, rarely seen at this price point. This network of precision resistors converts digital signals into an analog output, for a warmer, rounder, and more analog sound than the standard version of K11.
Equipped with USB-C, optical, and coaxial digital inputs, RCA analog line level outputs, and two headphone jacks (1/4″ single-ended and 4.4mm balanced), the K11 R2R acts as a bridge between your computer and phone to your headphones and speakers, allowing them to work together seamlessly with upgraded sound. Switchable low, medium, and high gain levels are available, enabling you to use the built-in amplifier at comfortable volume levels with most headphones.
Fully differential 24-bit R2R DAC array
An R2R ladder DAC employs a series of resistors with precise values arranged in a ladder configuration. Each step of the ladder corresponds to a bit in the digital signal, and the combination of these resistors translates the digital input into a corresponding analog voltage.
FiiO has equipped the K11 R2R with a newly-developed fully differential 24-bit R2R resistor array with four channels. It consists of 48 resistors per channel, totalling 192 high-precision, ultra-thin film resistors with an accuracy of 0.1% and low temperature drift between the four channels. Due to the precision required, high-quality R2R DACs can be expensive and complex to manufacture — but FiiO has made it happen at a breakthrough price point.
Thanks to the specially designed audio circuit architecture, it promises an organic, clean, and smooth output with a dark background. For those who crave a less “digital” sound, R2R can be a great option.
NOS/OS dual operating modes
Unlike the standard K11 which offers different DAC filters, the FiiO K11 R2R has two operating modes: NOS (non-oversampling) and OS (oversampling). These offer different sound characteristics.
In NOS mode, the original sampling rate is retained during signal processing, while in OS mode all signals are oversampled to 384kHz for processing. NOS mode results in a more musical presentation, while OS mode delivers more detail and clarity.
Inputs and outputs
With more inputs and outputs than typical entry-level models, the FiiO K11 R2R can cater to diverse audio setups.
It features digital inputs via USB-C, coaxial, and optical Toslink. The USB connection doesn’t draw power from your computer, tablet, or smartphone.
On the output side, there’s 6.35mm single-ended and 4.4mm balanced jacks to drive your headphones. Both are located on the front of the K11 R2R for convenient ergonomics. On the rear, you’ll find an RCA line output which can be adjusted up to a maximum of 2Vrms, interfacing with a variety of active speakers and external amplifiers. The digital coaxial input can also be switched to an output in USB mode.
Headphone amplifier
Under a 32-ohm load, the K11 R2R is capable of pushing 1300mW under balanced mode through the 4.4mm output. This allows it to easily drive many hi-fi earphones and headphones to better unlock their potential.
The K11 has three separate gain levels, each with its own volume curve. This provides a better listening experience with various types of headphones, whether you are using sensitive earphones or harder-to-drive over-ear headphones.
Slim and stable enclosure
The slim aluminum alloy body allows you to easily place the K11 R2R anywhere, making it easier to complement the rest of your desk. Thanks to the silicone antislip pad, the K11 R2R rests stably and firmly on your table.
High-contrast display
A custom, high-contrast display and durable VA display allows you to easily see the sampling rate, volume, gain, or output mode with just a glance.
RGB logo lighting
The FiiO logo is illuminated with RGB lighting, giving you a quick way to identify the sampling rate of the current audio being played back. Six LED strips work in conjunction with a carefully placed reflective film and parts of the body designed to reflect light to make the light show uniform and elegant. You can customize brightness, colour, and patterns via the multi-function knob.
Single knob interface
The K11 R2R’s minimalist design includes a single versatile knob to control power, volume, menu navigation, and more. The knob is designed so that you can quickly execute various complex actions by simply pressing and turning the knob. You can also quickly switch between line-out and headphone-out modes by double-pressing the knob, making it easier for you to switch your listening setup.
What’s included
- FiiO K11 R2R
- USB-A to USB-C Cable
- External Power Adapter
- AC Power Cable (North American)
- 6.35mm to 3.5mm Headphone Adapter
- Quick Start Guide
- 1-Year Warranty
