K13 R2R

Desktop R2R DAC and Headphone Amplifier
The FiiO K13 R2R brings the distinctive character of true R2R digital-to-analogue conversion to a versatile desktop audio component. Combining a fully differential 24-bit R2R DAC, powerful balanced headphone amplification, extensive connectivity and sophisticated sound customisation, it is designed to serve as the centre of a modern desktop Hi-Fi system.

Its combination of NOS and oversampling modes, high-resolution decoding, LDAC Bluetooth, balanced analogue circuitry and flexible preamplifier and line outputs allows the K13 R2R to accommodate a wide range of listening setups. With a carefully engineered power supply and a distinctive illuminated "skylight" design, it combines high-performance audio engineering with a refined contemporary appearance.

Fully Differential 24-Bit R2R Conversion
At the heart of the K13 R2R is FiiO's proprietary four-channel fully differential 24-bit R2R resistor array DAC. Each channel uses 48 precision thin-film resistors, resulting in a total of 192 resistors across the four-channel architecture.

Each resistor is manufactured to 0.1% accuracy with low temperature drift of 30ppm, allowing the resistor network to maintain precise conversion performance. The fully differential architecture also helps reduce noise and FFT harmonics, contributing to a darker and quieter background.

This carefully engineered R2R implementation gives the K13 R2R its distinctive musical character, combining detailed reproduction with the rich and engaging presentation associated with resistor ladder DAC technology.

NOS and Oversampling Modes
The K13 R2R provides two selectable digital processing modes, allowing listeners to choose between the character of Non-Oversampling and Oversampling operation.

In NOS mode, the original sampling rate is maintained during decoding. This approach preserves the native sampling characteristics of the source and provides an organic, natural presentation.

OS mode takes a different approach by upsampling the signal globally to 384kHz. This can provide a more refined and highly resolved presentation, giving listeners an alternative way to experience their music.

The choice between the two modes allows the K13 R2R to adapt to different recordings and personal listening preferences. Native 1-bit DSD decoding is also supported, although DSD playback may result in a slightly lower volume level, which can be compensated for using the volume control.

A Versatile Desktop Decoding Hub
The K13 R2R has been designed to perform more than simply convert digital audio. With a wide selection of inputs and outputs, it can operate as a versatile desktop decoding hub, preamplifier and headphone amplifier.

High-resolution audio support extends to PCM up to 32-bit/384kHz and DSD256, allowing the K13 R2R to handle demanding digital music sources with ease. Its XLR and RCA preamplifier and line outputs also allow it to connect directly to external amplification or powered speakers, making it suitable for both headphone-focused systems and complete desktop Hi-Fi setups.

Ten-Band High-Precision PEQ
The K13 R2R incorporates a ten-band parametric equaliser designed to provide detailed sound customisation across its operating modes. Powered by the XMOS XU316 platform and FiiO's proprietary tuning algorithms, the PEQ allows listeners to shape the sound according to their individual preferences.

Presets such as Retro PEQ provide convenient starting points, while users can create their own curves to simulate or correct headphone frequency responses. EQ curves can be exported, imported, shared and saved, making it easy to maintain different profiles for different headphones or listening preferences.

Auto-EQ functionality provides an additional way to customise the sound without requiring extensive manual adjustment. PEQ processing supports audio signals up to PCM 192kHz/24-bit.

For USB input, the PEQ can also be accessed through FiiO's web-based interface, while other operating modes can be adjusted through the FiiO Control app.

Fully Balanced Amplification
The K13 R2R uses a fully differential audio architecture throughout its signal chain. The R2R DAC, low-pass filter, volume control and headphone amplifier all use fully differential signal processing, helping provide excellent interference rejection, low distortion and high dynamic range.

The amplification stage incorporates adjustable gain to accommodate different types of headphones and in-ear monitors. Dedicated headphone protection mechanisms and pop noise elimination further enhance reliability and everyday usability, helping the K13 R2R deliver a clean and dependable listening experience.

Powerful Balanced Headphone Output
With up to 2400mW + 2400mW of balanced output power into a 32Ω load, the K13 R2R provides substantial current for a wide range of headphones and IEMs. The powerful amplifier is designed to reveal the detail and dynamic potential of high-fidelity headphones while providing sufficient drive for more demanding models.

Three selectable gain levels further improve compatibility, allowing the amplifier to be tailored to different headphone sensitivities. The K13 R2R also allows the headphone output and preamplifier output to maintain independent volume settings, providing greater flexibility when switching between different listening configurations.

Specially Designed Dual Power Supply
Power delivery is a fundamental part of the K13 R2R's design. Its internal 30W switching power supply is housed beneath an alloy nickel-plated shielding cover, helping to improve resistance to interference and maintain a cleaner power environment for the audio circuitry.

The unit also features an external DC power input, allowing users to connect a compatible higher-performance linear power supply for an alternative power delivery configuration and potentially different sonic characteristics.

The supported external supply specification is 12V with a minimum current rating of 2.5A and a 5.5 × 2.1mm connector.

Multi-Rail Power Architecture
The K13 R2R uses a sophisticated multi-rail power supply system incorporating up to 18 low-noise LDO regulators and five DC-DC converters. By providing dedicated power rails for different sections of the circuitry, the architecture is designed to deliver stable and clean power while reducing unwanted interaction between different circuit sections.

ELNA RA3 audiophile-grade electrolytic capacitors and specialised audio tantalum electrolytic capacitors are also used within the power supply. These carefully selected components contribute to stable power delivery and complement the R2R architecture's naturally rich and musical presentation.

High-Resolution LDAC Bluetooth
The K13 R2R provides high-resolution wireless playback through Bluetooth 5.4. Support for LDAC, AAC and SBC codecs allows compatible devices to stream music wirelessly while maintaining excellent audio quality.

LDAC support makes the K13 R2R particularly convenient for smartphone and tablet users who want to enjoy high-quality wireless Hi-Fi without requiring a physical connection. It provides an easy way to incorporate portable devices into a dedicated desktop listening system.

High-Contrast LCD Display
A custom high-contrast HD LCD display provides a clear overview of the K13 R2R's operating status. Sampling rate, volume level, gain and output mode can all be viewed at a glance, making it easy to monitor important settings during playback.

The display is designed for long-term use and can remain continuously illuminated without the risk of burn-in associated with some display technologies. This ensures important system information remains readily visible whenever the K13 R2R is in use.

Minimalist Aluminium Design
The K13 R2R continues FiiO's minimalist desktop design language while introducing a distinctive new visual element. Its thickened unibody aluminium alloy chassis provides a solid and refined foundation for the internal circuitry, while the new "skylight" design provides a visual window into the R2R resistor array.

Flowing illumination and vibrant colours give the resistor section a distinctive technological appearance, creating a visual connection between the component's exterior design and its unusual internal DAC architecture.

The result is a component that looks unmistakably modern while maintaining the clean and understated proportions associated with the K series.

Customisable RGB Lighting
The integrated RGB lighting provides both visual appeal and useful information. The lighting can indicate the current audio sampling rate, allowing users to identify the active digital signal at a glance.

Brightness and colour can be customised, while users can also choose whether the illumination pulses. This allows the K13 R2R's appearance to be tailored to individual preferences, from subtle ambient lighting to a more prominent visual display.

Three Gain Levels and Independent Volume Curves
Three gain levels allow the K13 R2R to adapt more effectively to different headphones and IEMs. Lower gain settings can be suited to more sensitive designs, while higher gain levels provide additional drive for headphones that require greater amplification.

The K13 R2R also memorises independent volume settings for the headphone output and preamplifier output. This makes switching between headphones and an external amplifier or active speaker system more convenient while helping prevent unexpected changes in listening level.

Comprehensive Protection
The K13 R2R incorporates a range of protection systems designed to safeguard the component during abnormal operating conditions. Overheating and overload protection can automatically activate when necessary, helping prevent damage to the unit.

Combined with the headphone protection and pop noise elimination incorporated into the amplification circuit, these features provide additional reassurance during everyday use.

Convenient Timer Shutdown
A built-in timer allows the K13 R2R to automatically switch off after a selectable period between one and 99 minutes. The timer operates once each time it is configured, providing a convenient way to ensure the component does not remain powered unnecessarily.

This can be particularly useful for relaxed listening sessions where the user may want the system to switch off automatically after falling asleep or stepping away.

A Complete Desktop Hi-Fi Solution
The FiiO K13 R2R combines the musical qualities of true R2R conversion with the flexibility required from a modern desktop audio component. Its fully differential 24-bit resistor array, NOS and OS processing modes, powerful balanced headphone amplifier and ten-band PEQ provide extensive opportunities for tailoring the listening experience.

With PCM up to 32-bit/384kHz, DSD256, LDAC Bluetooth, XLR and RCA preamplifier and line outputs, the K13 R2R can form the heart of a headphone system, desktop Hi-Fi setup or wider two-channel audio system. Its dual power supply architecture, multi-rail regulation and carefully selected audiophile-grade components further reinforce its focus on clean, stable and musical performance.

Finished with a solid aluminium chassis and distinctive illuminated skylight design, the K13 R2R brings together precision engineering, powerful amplification and the unique character of R2R conversion in a compact desktop component. It is a versatile solution for listeners seeking detailed, natural and engaging digital audio with extensive control over the final sound.