FIIO K5 PRO ESS: Stationary DAC amplifier based on ESS ES9038Q2M

The FiiO K5 Pro ESS is a high-performance desktop DAC and headphone amplifier that showcases exemplary design in the service of sound reproduction that features great transparency, richness and precision.

With K5 Pro ESS, you can enjoy extremely realistic and detailed music reproduction, revealing all its subtleties. The K5 Pro bridges the gap between your computer, powered speakers and headphones in an incredibly simple way to transport you to your favorite artists.

Regardless of the equipment used, the advantage of digital audio inputs is that they inherit the integrity of the transmitted signal for accurate reproduction. The K5 Pro lets you enjoy digital audio with coaxial S/PDIF and optical Toslink inputs supporting sampling rates up to 192 kHz. The K5 Pro can be used with many audio players and digital interfaces.

The K5 Pro’s amplifier stage is on par with the competition, with plenty of design space to integrate the components needed for superior analog amplification. This 4-stage design is capable of delivering incredible audio fidelity through the use of a second-order LPF, analog volume control, and voltage gain. Every part of this circuit works in perfect harmony, delivering excellent dynamic range and very good resolution.

The K5 Pro has a built-in ADC that allows you to use an RCA line input with adjustable volume. It restores the analog volume curve for smooth, precise control while eliminating unwanted noise and potential balance issues. This design also allows the K5 Pro to be used with a variety of different headphones with different sensitivities.

The all-aluminum body has been CNC polished several times and is carefully anodized and sandblasted. It effectively protects the K5 Pro’s circuitry from dust and shock, giving it a clean, modern look. In addition, its compact dimensions allow it to be easily integrated into a complete system.

The K5 Pro’s massive, beautifully integrated metal knob on the front panel allows you to conveniently adjust the volume level. The circular LED light surrounding this volume knob glows different colors depending on the sample rate of the file being played, adding a hint of color to the discreet body.

A finely tuned headphone amplifier circuit increases the AOP TPA6120’s output power by more than 60%, delivering a total power of 1.5W into a 32Ω load and up to 20Vpp into a 300Ω load. The K5 Pro will fit most headphones without issue, whether they have low or high impedance.

While it has a full complement of digital inputs, the K5 Pro also features an RCA line input. Not only is it more reliable than the 3.5mm line-in input, but it also allows you to enjoy better audio resolution. The RCA line output signal is adjustable to a maximum of 2 Vrms, allowing the K5 Pro to be used with both powered speakers and external amplifiers.

Test conditions: USB input, sine wave -5dB, high gain, 48 kHz 20 Hz-20 kHz, headphone output (32 ohm load) Blue curve: right channel Red curve: left channel Test conditions: Line input, sine wave

– 5dB, high gain, 20Hz-20kHz, headphone output (32Ω load) Blue curve: right channel Red curve: left channel The

K5 Pro circuits have an improved clock management system and superior decoding capabilities. For this, the XMOS XUF208 USB interface is used. It includes a completely new clock system and supports high sampling rates up to 32-bit 768 kHz PCM and DSD512.

The K5 Pro’s volume control uses the NJRC NW1195A analog chip, delivering a very low output noise level of -118dB, as well as the ability to adjust the audio level in 0.5dB increments. The combination of this volume control with the excellent JFET TI TPA6120 and OPA1642 AOPs contributes greatly to the K5 Pro’s playback quality.

Source selection and gain adjustments are made easy with two switches on the K5 Pro’s front panel. For amplification, the device offers 3 settings: low, medium and high. These settings allow you to use the K5 Pro with the vast majority of headphones and earbuds on the market for a comfortable listening experience. Low gain uses all hardware circuitry, so dynamic range and overall audio fidelity are unaffected.

The K5 Pro reaches new heights in audio reproduction with the high-performance ES9038Q2M DAC, which uses a 32-bit conversion architecture to deliver rich, detailed audio reproduction. Compared to the previous generation, distortion has been reduced by 50%, and line-out crosstalk has been increased by 6 dB, channel separation has been improved and dynamic range has been improved by 3 dB.

FiiO K5 Pro uses a specially designed 15V DC power supply to reduce noise.

Characteristics of FIIO K5 PRO ESS:

• Product Type: DAC Headphone Amplifier
• DAC chip: ESS ES9038Q2M
• USB Interface: XMOS XUF208
• Inputs: 1x USB-B 1x coaxial SPDIF 1x optical Toslink 1x stereo RCA line-in
• Outputs: 1x Stereo RCA Line Out 1x Headphone Out Jack 6.35mm
• Supported sampling rates: PCM up to 32 bit 768 kHz DSD up to DSD256
• OPA: TPA6120 OPA1642
• Adjustable Gain: 0dB 6dB 10dB
• Recommended headphone impedance: 16-300 ohms
• Headphone Output Power: 1250 mW @ SPDIF In, 32 Ohm, THD+N 1% 140 mW @ SPDIF In, 300 Ohm, THD+N 1% 1500 mW @ Line In, 32 Ohm, THD+N 1% 170 mW @ Line In, 300 Ohm, THD+N 1%
• Line Level: 2Vrms
• THD+N: Sortie ligne : 0.0012% (1 kHz, -10 dB, SPDIF In) / 0.0008% (1 kHz, Line In) Sortie casque : 0.0009% (1 kHz, 32 ohms, SPDIF In ) / 0.003% (1 kHz, 32 ohms, line input)
• Output impedance: 1.2 ohms
• Frequency response: 20 Hz – 50 kHz (-2 dB)
• SNR: Line Out: >= 115 dBA Headphone Out: >= 118 dBA
• Noise Floor: Line Out: = 3.5uV
• Crosstalk: Line Out: >= 95 dB Headphone Out: >= 80 dB (SPDIF Input) / >= 64 dB (Line In)
• Dimensions: 120.5 x 130 x 55 mm
• Weight: 480 g