FiiO K11 R2R desktop DAC and headphone amplifier with true 24-bit R2R, NOS/OS, DSD256 and 4.4mm balanced output. Natural, powerful and versatile. Read more.
The FiiO K11 R2R is a compact desktop DAC and headphone amplifier designed for listeners who deliberately want an alternative approach to digital-to-analogue conversion. Instead of relying on a conventional delta-sigma DAC chip, FiiO equips the K11 R2R with its own fully differential true 24-bit R2R resistor-array DAC. It therefore provides an accessible way to explore R2R conversion without immediately stepping up to a significantly more expensive high-end DAC.
The K11 R2R combines this distinctive conversion architecture with a capable headphone amplifier, USB-C, optical and coaxial digital inputs, RCA line output, a 6.35 mm headphone socket and a 4.4 mm balanced headphone output. It works equally well on a desk next to a computer or streamer and as a DAC or preamplifier in a compact hi-fi system.
Explore the complete range of FiiO products at Hi-Stands, our selection of high-quality DACs and our headphone amplifiers.
At the heart of the FiiO K11 R2R is a self-developed four-channel fully differential R2R DAC. Each channel uses two arrays of 48 precision thin-film resistors, giving the conversion stage a total of 192 precision resistors with 0.1% tolerance and low 30 ppm temperature drift.
R2R conversion uses carefully matched resistor networks to transform digital data into an analogue signal. This is fundamentally different from the delta-sigma architecture used in many modern DAC chips. Neither approach is automatically superior, but R2R gives the K11 R2R a clearly different technical design and allows FiiO to offer both NOS and OS operating modes.
In NOS or Non-Oversampling mode, the original sampling rate of the source material is maintained. This mode is often favoured by listeners who appreciate a direct and relaxed presentation.
In OS or Oversampling mode, the signal is upsampled to 384 kHz. Depending on the recording, headphones and personal preferences, this can create a different impression of definition and clarity. Being able to switch between both modes makes the K11 R2R particularly interesting for listeners who enjoy experimenting with their digital playback chain.
Via USB-C, the FiiO K11 R2R supports PCM up to 384 kHz/32-bit and DSD256. The coaxial digital input supports PCM up to 192 kHz/24-bit, while the optical input supports up to 96 kHz/24-bit. This makes it easy to use the K11 R2R with a PC, Mac, laptop, streamer, CD transport or another digital audio source.
Volume is handled by the NJW1195A four-channel electronic volume controller. Three gain levels – Low, Medium and High – each use a dedicated volume curve, allowing precise adjustment with both sensitive earphones and more demanding full-size headphones.
Into a 32-ohm load, the 4.4 mm balanced headphone output provides up to 1300 mW + 1300 mW. At 300 ohms, it delivers up to 220 mW + 220 mW. The 6.35 mm single-ended output delivers up to 460 mW + 460 mW at 32 ohms.
Together with its three gain settings, this gives the K11 R2R enough flexibility for a broad range of in-ear and over-ear headphones.
The K11 R2R is not limited to headphone listening. Its stereo RCA output allows it to operate as a standalone DAC or as a variable-output preamplifier. The multifunction control knob provides quick access to PO, PRE and LO operating modes.
This allows the K11 R2R to be connected directly to active speakers, an integrated amplifier or a power amplifier. The coaxial connector can also function as a digital output when USB is being used as the input source.
The K11 R2R shares its compact form factor and many connectivity options with the standard FiiO K11 desktop DAC and headphone amplifier, but the conversion architecture is fundamentally different.
The regular K11 uses a CS43198 DAC and provides up to 1400 mW + 1400 mW into 32 ohms from its balanced output. The K11 R2R provides 1300 mW + 1300 mW. The reason to choose the R2R version is therefore not additional output power, but FiiO's dedicated 24-bit R2R architecture and the ability to select NOS or OS conversion.
The standard K11 remains an excellent option for users looking for strong measured performance and slightly more maximum output power. The K11 R2R is the more distinctive choice for listeners specifically interested in R2R conversion.
If you want to combine FiiO's R2R technology with more output power, balanced XLR connections, Bluetooth and additional adjustment options, also consider the FiiO K13 R2R DAC/AMP. The K11 R2R remains the more compact and accessible route into FiiO's desktop R2R range.
| Model | FiiO K11 R2R |
| Type | Desktop DAC & headphone amplifier |
| DAC architecture | Fully differential true 24-bit R2R resistor array |
| R2R network | 192 precision resistors, 0.1% tolerance, 30 ppm temperature drift |
| Modes | NOS / OS |
| USB | Up to PCM 384 kHz/32-bit, DSD256 |
| Coaxial | Up to PCM 192 kHz/24-bit |
| Optical | Up to PCM 96 kHz/24-bit |
| Volume control | NJW1195A 4-channel electronic volume control |
| Gain | Low / Medium / High |
| 4.4 mm balanced | ≥1300 + 1300 mW @ 32 Ω; ≥220 + 220 mW @ 300 Ω |
| 6.35 mm single-ended | ≥460 + 460 mW @ 32 Ω; ≥50 + 50 mW @ 300 Ω |
| Recommended impedance | 8–150 Ω single-ended / 8–350 Ω balanced |
| SNR | ≥115 dB A-weighted |
| Frequency response | 20 Hz – 50 kHz |
| Digital inputs | USB-C, optical, coaxial |
| Analogue output | Stereo RCA line-out / pre-out |
| Bluetooth | No |
| Power supply | External 12 V / 2 A adapter |
| Dimensions | 147 × 133 × 32.3 mm including feet |
| Weight | Approx. 420 g |
The main difference is the DAC architecture. The regular K11 uses a CS43198 DAC, whereas the K11 R2R uses FiiO's own true 24-bit R2R resistor array and provides selectable NOS and OS modes.
No. The K11 R2R is a wired desktop DAC with USB-C, optical and coaxial digital inputs.
Yes. Its stereo RCA outputs allow the K11 R2R to function as either a DAC or a variable-output preamplifier.
Yes. DSD up to DSD256 is supported via USB.
NOS maintains the original sampling rate of the source signal. In OS mode, the signal is upsampled to 384 kHz. Both can be selected directly on the K11 R2R.
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