FiiO K11 R2R | Desktop Headphone DAC and Amp

Experience Pristine Digital Audio with the FiiO K11 R2R, a Desktop DAC and Headphone Amplifier that Delivers Reference-Level Sound

• Utilizes a Resistor Ladder DAC, known for its warm, analog sound
• Dual OPA1642 op-amps deliver ample power to drive demanding headphones
• Supports up to 384kHz/32bit and DSD256
• Multiple input options: USB, coaxial, and optical inputs
• Compact size and robust aluminum chassis, ideal for desktop setups

Specially Designed Audio Circuit

The audio signal is transmitted via a USB interface processor to a digital audio bridge. After being processed by an FPGA, it is sent to the R2R DAC for 4-channel output after decoding. It then passes through two Ti OPA1642 op-amps for low-pass filtering and single-ended analog signal converting, and transmits to the NJW1195A electronic volume control chip for precise volume adjustment. The output stage uses two SGM8262 op-amps for 4-way phase inversion and amplification, resulting in outputs of singed-ended and balanced analog signals.

The audio circuit features gain controls. It is complemented by a specially-designed headphone protection circuit and a pop noise elimination system, ensuring the audio circuit is both high quality in sound produced and reliable.

Specially Designed Power Supply

The K11 R2R uses up to 17 low-noise precision LDO precision regulator IC and 2 DC-DC converters. This provides a multi-channel specialized power supply of 9V, 8V, ±7.5V, ±6V, 5.4V, 3.3V, 1.8V, and 1.2V. These are combined with an external custom 12V switching power supply to ensure the purity of the power supplied and provide a solid foundation for stronger power input.

True 24bit Decoding

Support for PCM 384kHz/24bit and DSD256 decoding, means the K11 R2R can easily handle high-precision audio signals and fully exhibit the details within, providing you with an excellent audio experience. * DSD256 requires setting the DSD output mode to Native on the source device, internally converting to PCM before being decoded by the R2R resistor arrays.

Gain Levels and Volume Curves

The K11 R2R has three separate gain levels, each with its own volume curve. This allows a better listening experience with various types of headphones, whether you are using sensitive earphones or hard-to-drive over-ear headphones.

One Source of Control

In the K11 R2R’s minimalist design, the volume knob acts as a crucial source of total control. The K11 R2R’s multifunction volume knob is used to power the device on and off, accessing menu operations, making volume adjustment, and other functions.

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 LO/PO modes by double-pressing the knob, making it easier for you to appropriately connect to different headphones or audio setups.

Fully Differential True 24bit R2R DAC Resistor Arrays

FiiO’s newly self-developed four-channel fully differential 24bit R2R DAC consists of two 48 precision thin-film resistor arrays per channel, totaling 192 resistors with 0.1% tolerance and low temperature drift (30ppm). This configuration delivers a unique and charming sound.

Additional Features

Dual NOS/OS Modes
Non-Oversampling Mode: Maintains the original sampling rate for decoding, preserving authentic sound. Oversampling Mode: Upsamples globally to a high sampling rate of 384kHz, for superior audio performance and even more refined sound.

High-Quality Electronic Volume Control
The NJW1195A is a 4-channel electronic volume controller. This resistor ladder electronic potentiometer is low distortion and low noise, allowing precise volume adjustment.

Beryl Solid Capacitors
The capacitors’ ultra-low ESR, combined with excellent anti-interference capabilities, allow them to provide a stable and clean power supply and this achieve high-quality sound.

Powerful Output
Under a 32Ω load, the K11 R2R is capable of pushing 1300mW+1300mW under balanced modes. This allows it to easily drive many Hi-Fi headphones and fully unlock their potential.

Screen Full of Clarity
A custom, high-contrast and durable LCD screen allows you to easily see the sampling rate, volume, gain, or output mode with just a glance.

Phosphor Copper Metal Shielding
The shielding cover undergoes a passivation process, providing corrosion resistance and anti-oxidation capabilities. It effectively resists external interference, ensuring signals processed are accurate.

Specifications

• DAC: FIIO-developed R2R DAC
• SoC: GD32F303RE
• Supported Formats: 384kHz-32bit/DSD256 (USB DAC)
• Frequency Response: 20Hz-50kHz
• SNR: ≥ 115 dB
• Noise Floor: <5.1uV
• THD+N: 0.025% (1kHz/0dB@10KΩ)
• Adaptive Impedance: PO 8-150Ω, BAL 8-350Ω
• Power Supply: DC12V 2A
• SE Output
  • L+R≥660mW +660mW (16Ω, THD+N <1%)
  • L+R≥460mW +460mW (32Ω, THD+N <1%
  • L+R≥50mW+50mW (300Ω，THD+N＜1%）
•  BAL Output
  • L+R≥520mW+ 520mW (16Ω, THD+N <1%)
  • L+R≥1300mW+1300mW (32Ω, THD+N <1%)
  • L+R≥220mW+220mW (300Ω, THD+N＜1%）
• Weight: 15oz
• Dimensions: 5.7″ x 5.2″ x 1.2″

In the Box

• K11 R2R
• Power adapter
• Power cable
• USB data cable
• Headphone adapter
• Warranty card
• Quick start guide