The FiiO K13 R2R is a desktop USB DAC and headphone amplifier designed for serious listeners. It replaces chip-based conversion with a **fully differential 24-bit resistor ladder (R-2R)** network, offering an audio character that emphasizes clarity, warmth, and musical coherence. It accepts USB-C, optical, coaxial, and Bluetooth inputs, and provides both balanced and single-ended headphone outputs along with line-level outputs so you can integrate it into headphone and speaker setups. With three gain settings, it can handle anything from low-impedance IEMs to demanding full-size headphones, all within a single, elegant unit.
Key Features
- Four-channel fully differential R-2R DAC with 192 precision resistors for superior tonal balance
- Dual decoding modes (NOS / OS) with full support for PCM 384 kHz, DSD256, and extended formats
- High headphone output: up to 2,400 mW + 2,400 mW (balanced, 32 Ω), with low / medium / high gain control
- Comprehensive I/O: USB-C, optical (Toslink), coaxial, Bluetooth 5.4 (LDAC/AAC/SBC) inputs
- Balanced XLR and dual RCA line outputs; 4.4 mm balanced and ¼" single-ended headphone jacks
- Built-in parametric 10-band EQ, OLED display, and customizable filter options
- Robust internal design: dual DC/AC power supplies, shielded switching PSU, and option for external 12 V input
Why Buy
You should choose the K13 R2R if you want a single desktop unit that bridges digital sources and high-performance headphones or speakers, while delivering a musical, low-noise listening experience. It’s ideal for users who demand both technical capability and musical ease in everyday use.
- A single unit that covers digital decoding and headphone amplification across a wide variety of devices
- Exceptional output power and adjustable gain mean compatibility with both sensitive IEMs and high-impedance headphones
- Feature-rich control (EQ, modes, filter choice) gives you flexibility to tailor sound without extra gear
Product Specifications
| Specification | Details |
|---|---|
| Product Name | FiiO K13 R2R |
| Model | K13 R2R |
| Category | Desktop USB DAC & Headphone Amplifier |
| DAC | FIIO-developed four-channel fully differential 24-bit R-2R resistor array DAC (48 precision thin-film resistors per channel; 192 resistors total) |
| Hardware / Decoding | SoC: ESP32-S3; USB decoding: XU316; Amplifier: OPA1642 ×2 + TPA6120A ×2 |
| Supported digital formats | USB: PCM up to 384 kHz / 32-bit; native DSD256. Coaxial/Optical: up to 192 kHz / 24-bit (Coax DSD64). OS / NOS modes supported. MQA full decoding supported. |
| Bluetooth | Bluetooth 5.4 — SBC / AAC / LDAC (receiver) |
| Digital Inputs | USB-C ×2 (data), Optical (Toslink), Coaxial (RCA), Bluetooth |
| Analog Outputs | Balanced line out: XLR3; Single-ended line out: RCA ×2; Headphone outs: 4.4 mm balanced, 6.35 mm (¼") single-ended |
| Headphone output (balanced 4.4 mm, OS mode) |
High gain: L+R ≥1200mW+1200mW (16Ω) and L+R ≥2400mW+2400mW (32Ω); Medium gain: L+R ≥1200mW+1200mW (16Ω) and L+R ≥1300mW+1300mW (32Ω); Low gain: L+R ≥610mW+610mW (16Ω) and L+R ≥330mW+330mW (32Ω) |
| Headphone output (single-ended 6.35 mm, OS mode) |
High gain: L+R ≥1200mW+1200mW (16Ω) and L+R ≥1220mW+1220mW (32Ω); Medium gain: L+R ≥660mW+660mW (16Ω) and L+R ≥340mW+340mW (32Ω); Low gain: L+R ≥165mW+165mW (16Ω) and L+R ≥85mW+85mW (32Ω) |
| Output impedance | Single-ended <0.4 Ω (measured at 32 Ω); Balanced <1 Ω (measured at 32 Ω) |
| Adaptive impedance | PO / BAL: 8 – 350 Ω |
| Key audio numbers | THD+N ≈ 0.0173% (1 kHz / -6 dB @32 Ω); SNR ≥117 dB (A-weighted) typical; Dynamic range ≥108 dB |
| PEQ / Filters | 10-band PEQ supported (configurable via FiiO Control); OS / NOS filter options |
| Display & indicators | 1.1" LCD (shows sampling rate, volume, gain, output mode); top knob indicator LED with customizable brightness / RGB pulsing |
| Controls | Volume knob (push to select) + menu knob; IR remote included; FiiO Control app support; driver-free USB DAC mode supported |
| Firmware updates | MCU firmware via side USB-C; XMOS firmware via side/rear USB-C; Bluetooth firmware via FiiO Control app |
| Power | AC 100–240 V ~ 50/60 Hz; or DC 12 V / ≥2.5 A (either-or). No internal battery. |
| Accessories included | Unit; AC power cord; IR remote control; USB data cable; headphone adapter; quick start guide; warranty card |
| Dimensions | About 210 × 188 × 42 mm (including feet) |
| Weight | About 980 g |
| Notes | Driver-free mode supported; multiple gain settings (Low / Medium / High); option to use AC or DC power. |