FiiO K19 silver

The FiiO K19 is a desktop headphone amplifier with DAC that incorporates technologies previously used in professional equipment, all within a compact and refined chassis. It features two ES9039SPRO converters, a dedicated DSP processor, and delivers high output power. The K19 is a versatile solution suitable for audiophiles as well as home theater enthusiasts.

Cutting-Edge Technical Architecture

At the heart of the K19 lies a completely redesigned architecture built around a quad-core FPGA processor—a first for FiiO. This component manages all incoming digital signals—USB, Bluetooth, coaxial, optical, and HDMI—before transmitting them via two dedicated I2S buses to the ES9039SPRO converters. This approach ensures perfect separation of processing and minimizes interference.

The ACCUSILICON AS318-B femtosecond oscillators are another distinctive feature. These components, usually reserved for laboratory measurement equipment, deliver an exceptionally precise clock signal, drastically reducing jitter. The ADI ADSP-21565 SHARC+ DSP processor completes the setup by handling the 64-bit calculations required for the parametric equalizer.

The amplification section relies on eight THX AAA 788+ modules configured in a fully balanced architecture. This parallel configuration achieves remarkable power levels while maintaining distortion below 0.0003%. The I/V conversion stages use OPA1612 and OPA2211 operational amplifiers, renowned for their linearity and low noise.

Power and Versatility

With 8 watts per channel into a 32-ohm load on the balanced output, the K19 ranks among the most powerful amplifiers in its class. This power reserve allows it to efficiently drive demanding planar magnetic headphones like HiFiMAN or Audeze, while maintaining perfect control over more sensitive models.

The five-position gain system automatically adapts to the detected impedance, optimizing the signal-to-noise ratio for each setup. Multiple outputs—6.35 mm single-ended jack, XLR4, and 4.4 mm balanced jack—offer total flexibility. RCA and XLR line outputs also allow the K19 to be integrated into a traditional hi-fi system.

Revolutionary Parametric Equalizer

The 31-band equalizer is one of the K19’s major innovations. Unlike traditional graphic equalizers, this parametric system allows precise adjustment of the center frequency, bandwidth (Q factor), and gain of each filter. Calculations are performed in 64-bit floating point, preserving the signal’s native resolution.

This feature transforms the K19 into a true acoustic correction tool, capable of compensating for a headphone’s response flaws or tailoring the sound signature to personal preferences. The FiiO Control app simplifies configuration with preset curves and allows saving multiple profiles.

Universal Connectivity and Home Theater Integration

The K19’s connectivity far surpasses that of traditional DAC/amplifiers. The HDMI ARC input, rare in this category, enables direct integration with a TV or home theater processor. This function turns the K19 into a central audio hub, capable of processing multichannel signals and delivering them in high-quality stereo.

Full MQA decoding on USB and digital inputs ensures compatibility with high-resolution streaming services. The Qualcomm QCC5125 Bluetooth supports advanced LDAC and aptX HD codecs, offering wireless quality close to wired. Coaxial and optical digital outputs allow for daisy-chaining other equipment.

Premium Construction and Design

The CNC-machined unibody aluminum chassis reflects meticulous attention to detail. The 2 mm wall thickness ensures exemplary rigidity while facilitating heat dissipation. The physical separation of digital and analog circuits, reinforced by multilayer internal shielding, eliminates parasitic interference.

The modular design allows for horizontal or vertical positioning thanks to the included stand. The 1.3-inch color TFT screen clearly displays playback information and makes menu navigation easy. The ALPS tactile feedback potentiometer offers remarkable adjustment precision throughout its range.

Reference Sound Signature

Tests converge on a neutral and balanced sound signature, faithful to the original recording. The K19 favors transparency and resolution over coloration, revealing the subtlest nuances in recordings. The dynamics impress with their range and precision, especially notable in complex orchestral passages.

The soundstage, while sometimes perceived as slightly narrow in width, excels in depth and placement accuracy. Instrument separation remains exemplary even in the densest arrangements. The bass extends deeply without ever masking the mids, while the highs retain their sparkle without harshness.

Comparison with the Previous Generation

The K19 represents a significant technological leap compared to the K9 Pro ESS. The power is doubled, the addition of the DSP processor and parametric equalizer completely transform the product approach. Where the K9 Pro offered quality conversion, the K19 provides a true audio processing center.

HDMI integration and home theater features significantly broaden its scope. The more refined design and reinforced construction justify its premium positioning. Only the price, which is twice as high, may deter users accustomed to the brand’s traditional value-for-money.

Technical Specifications

Audio Conversion and Processing

• Digital-to-analog converters: 2 × ESS ES9039SPRO (8 channels each)
• Digital signal processor: ADI ADSP-21565 SHARC+ (800 MHz, 64-bit double-precision calculations)
• Clocks: 2 × ACCUSILICON AS318-B femtosecond, low phase noise
• Parametric equalizer: 31 lossless bands, adjustable
  • Gain: +12 dB to -24 dB
  • Q factor: 0.4 to 128 dB
• Supported HDMI frequencies: up to 192 kHz / 24-bit (input/output), 44.1 / 48 kHz (ARC)
• Full MQA decoding: USB and digital inputs

Amplification

• Headphone amplifier: 8 × THX AAA 788+ (fully balanced architecture)
• Headphone output power (6.35 mm)
  • 32 Ω: up to 2300 mW per channel (ultra-high gain)
  • 300 Ω: up to 270 mW per channel
• Balanced output (4.4 mm / XLR4)
  • 32 Ω: up to 8000 mW per channel
  • 300 Ω: up to 1100 mW per channel
• Total harmonic distortion + noise: < 0.0003% (headphone), < 0.00025-0.00032% (line)
• Signal-to-noise ratio: ≥ 127 dB (headphone), ≥ 128 dB (balanced)
• Crosstalk: ≥ 120 dB
• Noise floor: < 3.5 μV
• Gain levels: 5 steps from low to ultra-high

Connectivity and Interfaces

• Digital inputs: USB, Bluetooth, coaxial, optical, HDMI ARC / input / output
• Outputs: 6.35 mm headphone, balanced 4.4 mm / XLR4, RCA / XLR line out
• Digital outputs: coaxial, optical
• USB interface: XMOS XU316 with MQA support
• Bluetooth: Qualcomm QCC5125
  • Supported codecs: LDAC, aptX HD / Adaptive, AAC, SBC
• Trigger ports: 12 V input / output
• Ground / isolation switch
• Impedance compatibility
  • Headphone output: 8-150 Ω
  • Balanced output: 8-350 Ω

Control and Display

• Screen: 1.3-inch color laminated TFT
• Control: FIIO Control app (mobile / PC) + infrared remote
• Rotary knob with multicolor LED indicators
• Sampling rate indicators
• Bluetooth LED indicators for codec identification
• Operating modes
  • PO + PRE OUT (default): headphone + rear output with volume control
  • PO only: headphone (adjustable volume)
  • PRE OUT only: rear output (adjustable volume)
  • LO: fixed output
  • Coaxial / optical: standard digital output

Construction and Design

• Body: CNC-machined unibody aluminum alloy
• Design: ultra-slim, robust, and shock-resistant
• Complete separation of digital / analog circuits
• Internal shielding for DAC, DSP, headphone amplifier
• Audiophile-grade components
  • Capacitors: WIMA, ELNA, Panasonic
  • Resistors: MELF for thermal stability
  • Internal wiring: silver-plated oxygen-free copper
• Dimensions: 250 × 225 × 36.7 mm
• Weight: approx. 1.8 kg

Power Supply and Cooling

• Internal power supply: 40 W (AC 85-305 V)
• DC input: 15 V ≥ 3 A
• Heat dissipation via thermally conductive materials
• Aluminum body with honeycomb vents
• Internal and external passive thermal convection
• USB driverless mode: plug and play on most operating systems

Accessories and Compatibility

• Box contents
  • FIIO K19 DAC / amplifier
  • Infrared remote control
  • Vertical stand
  • High-quality internal wiring
  • User guide
• System compatibility: Windows, macOS (parametric EQ control)
• FIIO Control mobile app
• Compatible with all high-impedance headphones
• Firmware update: via USB and FIIO Control app