The FIIO K19 is a studio-grade flagship Digital-to-Analog Converter (DAC) and headphone amplifier. The actual way to pronounce the model is “K-one-nine” instead of “K-nineteen”, this is because it is the second-generation K9 series where the first number denotes the generation.

Key Features of the FIIO K19
- 2x 8-channel ESS9039SPRO DAC chip
- 8-channel THX AAA 788+ Amplifier
- 31-band high-precision lossless PEQ
- 8000mW + 8000mW powerful output
- Improved heat dissipation by 30% compared to K9 Pro
- Separated and shielded analog and digital audio circuit boards
Conversation with FIIO at CanJam 2024
I met Moses Ren, FIIO Lead Engineer for K19, at the CanJam Singapore 2024 and told me that the K19 took 14 months from concept to production. He highlighted that the star feature of the FIIO K19 is the 31-band PEQ made possible with the ADI ADSP-21565 DSP chip featuring high clock frequency of 800MHz and capable of 64-bit double precision floating point calculations. The PEQ settings can also be imported and exported, allowing sharing among the user community.

Besides the usual coaxial, optical, balanced XLR connectors, the K19 also supports HDMI IN and HDMI OUT/ARC, allowing homeowners to upgrade their home theatre audio experience. Just like R7 and R9, the K19 supports both AC and DC dual power supply.
The FIIO K19 design and specs are the result of constant feedback received from customers, something that FIIO takes pride in. Moses elaborated that the K19 offers great versatility for the owner to position the unit either horizontally or vertically. The design team also created various prototypes, but ultimately settled with the honeycomb mesh design that is more durable. It also facilitates heat dissipation, and as a result, the heat build-up is reduced by 30 percent.

The retail package also includes a headphone stand support and a vertical stand with matching colour to the finishing as well as padding stickers for horizontal placement. Screwdriver is also included, as well as a remote control.
Setting Up, Design and Operations
During setup, you have to decide whether you want to place the K19 vertically or horizontally. If vertical, you have to screw in the stand after removing the sticker labels. If horizontal, you can stick the silicone leg pads. I opted for the horizontal placement as I have a space on top of my OPPO multi-player.

The LED display is vertically-aligned by default, as are the knob llabels, so the first thing to do is to change the display orientation. I would very much like the LED display to be larger so that it can show more information at one glance. Navigation is also through one of the knobs which is arguably less intuitive than navigation buttons (you turn counterclockwise to move the cursor down the line). There is a wasted opportunity to have separate colour indicators for both knobs so that they can offer more combination. For now, the colours indicate the source resolution and the encoding format.

The rear panel is crowded with dozens of connectors, allowing you to interface all sorts of digital and analogue connectors with the K19. These include coaxial in/out, optical in/out, XLR, two RCA out, HDMI in, HDMI ARC. Apart from USB, the rest of the digital connectors have maximum sampling rates in their respective formats. For instance, optical ports support up to 24-bit 96kHz, so if your USB input is higher than this, there is no audio transmitted to the optical output.

The K19 does not support analogue inputs, which is consistent with all their DAC products. It’s a bummer for homeowners with vinyl record turntables or tape decks. For that, you need an ADC device, and lucky for me, I have the Creative Soundblaster X5, an amazing multi-IO headphone amp that supports both RCA in-out and optical in-out.
Navigating the display menu is using the second knob. Turn it without clicking is to change the input source, click it will enter the menu to select by rotating the knob counter clockwise. The first knob is used for power, mute and volume control. As each turn is to adjust one volume step, it would require a lot of turns to move the volume level, not as quick as traditional volume knobs.

The FIIO K19 offers a unique capability to customise the audio with a 31-band parametric EQ from the software interface connected to the RS232 port. Each band can be adjusted between -24dB and +12dB with a Q-value range of 0.4dB to 128dB. The adjustments can also be saved and shared to any K19 user. This feature will be extremely useful for audiophiles to tweak the frequency curves to finetune the headphones sound. With five levels of gain, the K19 can drive any headphones. The RS232 port is in the form of USB-C connector and it can only carry PEQ data. If you want to use the same computer as audio source, you need to connect a separate USB-C.
The entire aluminium alloy chassis is part of the heat dissipation system to transfer heat from the internal components via thermally conductive material. There is no internal fan, so during operations, the body feels very hot as intended, reach about 43 degrees Celsius. The K19 is three times more powerful than the K9 Pro but generates 30% less heat. You definitely should put the K19 in a well-ventilated area, and a vertical placement is definitely better, although not essential.

Audio Quality
The words I would describe the FIIO K19 are “power in control”, “articulated”, “clean layering”. The K19 provides extra sauce on the the source file to give better clarity, precise dynamics, without sounding hasty nor messy. There is a feeling of control in the audio production, not shouty, not muddy, not veiled. There is no excessive transparency, yet a light-handed sparkle provides more audible details. Sound staging is also not exaggerated, but little spatial, enough to give the recording a bit of space so it feels less tight while still getting better sonic separation. Playing with bit-perfect software like foobar2000 through FIIO ASIO driver really brings out the quality and makes me realise the mediocracy of Windows audio driver. Using Bluetooth as a wireless audio source also delivers clean and dynamic sound, and allows me to listen with better wired headphones when using my smartphone. It supports SBC, AAC, aptX, aptX LL, aptX Adaptive, aptX HD, and LDAC codecs.
I did a comparison with the Burson Playmate and felt that the musical performance is almost similar, but the Playmate vocals are a more intimate. Comparing to the Creative Sound Blaster X5, the X5 treble is yet a little more forward than the Playmate. Overall, I enjoy listening to the K19 more because the lead track is slightly laid back and slightly more spatial and diffused, providing a little less fatiguing experience. Ultimately, the tuning can be refined with the 31-band parametric EQ.

Verdict
The FIIO K19 demonstrates multiple aspects of product improvements. The new vertical design takes up less table space, the internal hardware is further elevated to produce improved audio refinements. During my review period, when I use the K19 to listen to all my music – from laptop, smartphones, CD player, turntable – as I turn up the volume, I get to enjoy more powerful sound but not noisy. Obviously the quality of headphones also play a part. I review with the FIIO FT3, the Sennheiser HD 800S and HD 620S, and even the upcoming ROG Delta II gaming headphones. I can say that the K19 brings out the best of their performances.
The ability to refine the sound signature using 31-band EQ is also unique for a DAC amplifier, and will offer headphone enthusiasts an avenue to finetune and get the desired sound. The FIIO K19 retails in Singapore for S$2099, available exclusively from the authorised reseller, AV One.