General Specifications
Name/Model K13 Hardware solution SoC: ESP32-S3, DAC: ES9039Q2M*2, USB decoding: XU316, AMP: OPA1642*2 + TPA6120A*2
Working mode USB DAC mode/Optical decoding mode/Coaxial decoding mode/Bluetooth receiving mode Color Black/Silver
Weight About 960g Dimensions About 210x188x42mm (including feet)
Gain L/M/H Remote control Supports IR remote control (only the one included in the accessory)
Volume control Knob/Remote control FIIO Control Supported
Driver-free mode (switch mode) Supported Bluetooth receiving (5.4) SBC/LDAC
Screen status indication Sampling rate, volume, gain, output mode, etc. PEQ Supports 10-band PEQ (PEQ is not available when using digital output)
MQA Supports MQA full decoding Knob indicator light/Top ambient light Supports customizing brightness and color, and supports always-on indication or RGB pulsing
Display 1.1-inch LCD Firmware upgrade MCU firmware: Upgrade through the side USB-C port
Max. supported sampling rate (PEQ=OFF) USB decoding: 768kHz/32bit; DSD512 XMOS firmware: Upgrade through the side or rear USB-C port
Coaxial decoding: 192kHz/24bit; DSD64 Bluetooth firmware: Upgrade through the FIIO Control app
Optical decoding:  96kHz/24bit Adaptive impedance PO: 8~350Ω
Coaxial output: 96kHz/24bit (USB decoding only) BAL: 8~350Ω
Filter settings Supports 8 filter settings  SHR (Second harmonic regulation) Supports 4 settings
Buttons and Ports
Knob Volume knob with button*1 + Menu knob with button*1 USB port Type-C USB*2 (Data transmission port)
Digital coaxial input port RCA plug (Input/Output) Digital coaxial output port RCA plug (Input/Output)
Balanced output port Standard 4.4mm port Digital optical input port Optical port
Balanced line output port XLR3 balanced port Headphone output port Standard 6.35mm port
Toggle switch Power toggle switch Single-ended line output port RCA port*2
Power Supply Parameters
Power supply AC 100–240V~50/60Hz; DC 12V/≥2.5A (either-or) 　 　
Audio Parameters
Performance and parameters of headphone output (6.35mm out, USB DAC/Coaxial decoding/Optical decoding, High gain)
Output power 1 L+R≥1200mW+1200mW (16Ω, THD+N＜1%, 4.4Vrms) Output impedance ＜0.4Ω (32Ω)
Output power 2 L+R≥1220mW+1220mW (32Ω, THD+N＜1%, 6.2Vrms) Crosstalk ≥77dB (1kHz@32Ω)
Output power 3 L+R≥150mW+150mW (300Ω, THD+N＜1%, 6.7Vrms) THD+N About 0.000435% (1kHz/-2dB@32Ω)
Noise floor ＜4.5μV (A-weighted) SNR ≥123dB (A-weighted)
Frequency response 20Hz~20kHz: attenuation＜0.2dB Dynamic range ≥123dB (A-weighted)
20Hz~80kHz: attenuation＜2.9dB Peak output voltage ＞19Vp-p
Performance and parameters of headphone output (6.35mm out, USB DAC/Coaxial decoding/Optical decoding, Medium gain)
Output power 1 L+R≥660mW+660mW (16Ω, THD+N＜1%, 3.3Vrms) Output impedance ＜0.4Ω (32Ω)
Output power 2 L+R≥340mW+340mW (32Ω, THD+N＜1%, 3.3Vrms) Crosstalk ≥77dB (1kHz@32Ω)
Output power 3 L+R≥35mW+35mW (300Ω, THD+N＜1%, 3.3Vrms) THD+N About 0.0004% (1kHz/-3dB@32Ω)
Noise floor ＜3μV (A-weighted) SNR ≥121dB (A-weighted)
Frequency response 20Hz~20kHz: attenuation＜0.2dB Dynamic range ≥121dB (A-weighted)
20Hz~80kHz: attenuation＜2.9dB Peak output voltage ＞9Vp-p
Performance and parameters of headphone output (6.35mm out, USB DAC/Coaxial decoding/Optical decoding, Low gain)
Output power 1 L+R≥165mW+165mW (16Ω, THD+N＜1%, 1.6Vrms) Output impedance ＜0.4Ω (32Ω)
Output power 2 L+R≥85mW+85mW (32Ω, THD+N＜1%, 1.6Vrms) Crosstalk ≥77dB (1kHz@32Ω)
Output power 3 L+R≥10mW+10mW (300Ω, THD+N＜1%, 1.6Vrms) THD+N About 0.00049% (1kHz/0dB@32Ω)
Noise floor ＜3μV (A-weighted) SNR ≥115dB (A-weighted)
Frequency response 20Hz~20kHz: attenuation＜0.2dB Dynamic range ≥115dB (A-weighted)
20Hz~80kHz: attenuation＜2.9dB Peak output voltage ＞5Vp-p
Performance and parameters of single-ended line output (RCA out, USB DAC/Coaxial decoding/Optical decoding)
THD+N About 0.00053% (1kHz/-3dB@10KΩ) SNR ≥122dB (A-weighted)
Crosstalk ≥110dB Noise floor ＜2.2uV (A-weighted)
Frequency response 20Hz~20kHz: attenuation＜0.2dB Dynamic range ≥122dB (A-weighted)
20Hz~80kHz: attenuation＜2.9dB Line output level 2.6Vrms (1kHz@10kΩ)
Output impedance ＜200Ω (10KΩ) 　 　
Performance and parameters of balanced headphone output (4.4mm out, USB DAC/Coaxial decoding/Optical decoding, High gain)
Output power 1 L+R≥1200mW+1200mW (16Ω, THD+N＜1%, 4.4Vrms) Output impedance ＜1Ω (32Ω)
Output power 2 L+R≥2400mW+2400mW (32Ω, THD+N＜1%, 8.8Vrms) Crosstalk ≥111dB (1kHz@32Ω)
Output power 3 L+R≥600mW+600mW (300Ω, THD+N＜1%, 13.5Vrms) THD+N About 0.00034% (1kHz/-4dB@32Ω)
Noise floor ＜8.3μV (A-weighted) SNR ≥120dB (A-weighted)
Frequency response 20Hz~20kHz: attenuation＜0.2dB Dynamic range ≥120dB (A-weighted)
20Hz~80kHz: attenuation＜2.9dB Peak output voltage ＞38Vp-p
Performance and parameters of balanced headphone output (4.4mm out, USB DAC/Coaxial decoding/Optical decoding, Medium gain)
Output power 1 L+R≥1200mW+1200mW (16Ω, THD+N＜1%, 4.4Vrms) Output impedance ＜1Ω (32Ω)
Output power 2 L+R≥1300mW+1300mW (32Ω, THD+N＜1%, 6.5Vrms) Crosstalk ≥112dB (1kHz@32Ω)
Output power 3 L+R≥145mW+145mW (300Ω, THD+N＜1%, 6.6Vrms) THD+N About 0.00036% (1kHz/0dB@32Ω)
Noise floor ＜4.6μV (A-weighted) SNR ≥123dB (A-weighted)
Frequency response 20Hz~20kHz: attenuation＜0.2dB Dynamic range ≥123dB (A-weighted)
20Hz~80kHz: attenuation＜2.9dB Peak output voltage ＞19Vp-p
Performance and parameters of balanced headphone output (4.4mm out, USB DAC/Coaxial decoding/Optical decoding, Low gain)
Output power 1 L+R≥610mW+610mW (16Ω, THD+N＜1%, 3.1Vrms) Output impedance ＜1Ω (32Ω)
Output power 2 L+R≥330mW+330mW (32Ω, THD+N＜1%, 3.2Vrms) Crosstalk ≥110dB (1kHz@32Ω)
Output power 3 L+R≥35mW+35mW (300Ω, THD+N＜1%, 3.3Vrms) THD+N About 0.0004% (1kHz/0dB@32Ω)
Noise floor ＜4.6μV (A-weighted) SNR ≥117dB (A-weighted)
Frequency response 20Hz~20kHz: attenuation＜0.2dB Dynamic range ≥117dB (A-weighted)
20Hz~80kHz: attenuation＜2.9dB Peak output voltage ＞9.5Vp-p
Performance and parameters of balanced line output (XLR3, USB DAC/Coaxial decoding/Optical decoding)
THD+N About 0.00034% (1kHz/-3dB@10KΩ) SNR ≥124dB (A-weighted)
Crosstalk ≥120dB Noise floor ＜3.4uV (A-weighted)
Frequency response 20Hz~20kHz: attenuation＜0.2dB Dynamic range ≥124dB (A-weighted)
20Hz~80kHz: attenuation＜2.9dB Line output level 5.3Vrms (1kHz@10kΩ)
Output impedance ＜300Ω (10KΩ)