Home Amps/DACS FiiO K9 Pro Review: Is It Still Worth A Purchase?

FiiO K9 Pro Review: Is It Still Worth A Purchase?

The original K9 Pro was an excellent recommendation. Is there something even better to consider now?

by Stuart Charles Black
>AFFILIATE DISCLOSURE: As an Amazon Associate I earn from qualifying purchases. As an eBay affiliate I earn from qualifying purchases.

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Big thank you to Apos for sending botht the K9 Pro AKM and K9 Pro ESS!

Greetings mate and Welcome aboard.

Stuart Charles here, HomeStudioBasics.com helping YOU make sound decisions leading to a beautiful audio experience that will make you fall in love with music (NOT gear), all over again, so…

In this comprehensive review, we will delve into the world of high-fidelity audio with a close examination of the FiiO K9 Pro (AKM version).

We’ll explore its various facets, from the design and aesthetic appeal to its features, connectivity options, sound quality, power output, and even how it stacks up against its siblings and competitors like the K5 Pro, Neo iDSD, K9 Pro ESS, and K9 (non-pro) version.

At the very very end, you’ll find Specifications, the Photo Gallery, and the Media I used to demo the K9 Pro.

Let’s dive in!

At A Glance

FiiO K9Pro Amplifier High Resolution Desktop DAC Headphone Amps THX-AAA 788+/Support 384 kHz/Native DSD256/MQA Decoding/LDAC/AptX Adaptive/AptX HD
FiiO K9Pro Amplifier High Resolution Desktop DAC Headphone Amps THX-AAA 788+/Support 384 kHz/Native DSD256/MQA Decoding/LDAC/AptX Adaptive/AptX HD
Max Sample Rate/Resolution
384kHz / 32-Bit (DSD256)
2x RCA Unbalanced, 1x 4.4mm TRS, 1x Coaxial, USB Type-B, Bluetooth S/PDIF, 1x TOSLINK Optical S/PDIF
2x RCA Unbalanced, 2x XLR 3-pin Balanced,
Headphone Outputs
1/4" Unbalanced, XLR 4-pin Balanced, 4.4mm Balanced
Power Output
1/4": 278mW @ 300 Ohms, XLR 4-pin: 278mW @ 300 Ohms, 4.4mm: 1.1W @ 300 Ohms
Output Impedance
< 1 Ohms (32-Ohm Load)
6.2 lb / 2.8kg
Price not available
Learn More
FiiO K9Pro Amplifier High Resolution Desktop DAC Headphone Amps THX-AAA 788+/Support 384 kHz/Native DSD256/MQA Decoding/LDAC/AptX Adaptive/AptX HD
FiiO K9Pro Amplifier High Resolution Desktop DAC Headphone Amps THX-AAA 788+/Support 384 kHz/Native DSD256/MQA Decoding/LDAC/AptX Adaptive/AptX HD
Max Sample Rate/Resolution
384kHz / 32-Bit (DSD256)
2x RCA Unbalanced, 1x 4.4mm TRS, 1x Coaxial, USB Type-B, Bluetooth S/PDIF, 1x TOSLINK Optical S/PDIF
2x RCA Unbalanced, 2x XLR 3-pin Balanced,
Headphone Outputs
1/4" Unbalanced, XLR 4-pin Balanced, 4.4mm Balanced
Power Output
1/4": 278mW @ 300 Ohms, XLR 4-pin: 278mW @ 300 Ohms, 4.4mm: 1.1W @ 300 Ohms
Output Impedance
< 1 Ohms (32-Ohm Load)
6.2 lb / 2.8kg
Price not available
Learn More

FiiO K9 Pro (AKM)

Price: Check Amazon! | Check Apos! | Check B&H! | Song Playlist: Here!

In The Box

FiiO K9 Pro Amp/DAC

USB Type-A to Type-B Cable

Power Cable

Bluetooth Antenna

1/4″ Headphone Adapter

Quick Start Guide

Warranty Card

FiiO K9 Pro Review

FiiO K9 Pro Review


After receiving the K9 (non-pro) version in the mail, I thought I’d revisit this K9 Pro article and help you determine which is most worthy of a purchase.

By the end, you’ll know the differences between them and we’ll make a value judgment based on price to performance, features, etc. The article will also compare the K9 series with some other Amps and DACS I’ve heard over the years.

With that, let’s dive in!

I think it’s safe to say that FiiO and quality go hand in hand.

Sure, they have a few minor issues that need to be ironed out (namely a sometimes sluggish Bluetooth response), but by and large, investing in their products is a safe bet and I’ve never had anything they’ve sent break down on me or cease to function dating back to 2018.

What Is It?

The FiiO K9 Pro is a digital-to-analog converter (DAC) and headphone amplifier roughly the size of Big Pun, designed to cater to audiophiles and music enthusiasts.

It functions as a standalone audio device, acting as an intermediary between digital audio sources, such as computers or mobile devices, and headphones or external speakers.

Build & Design

When I tell you this thing is mammoth, I truly mean it.

It’s almost as if the folks over at FiiO sat down one day, surveyed the current market of do-all Amp/DACS, and decided to one-up everybody like Scarface.


FiiO K9 Pro Review

Remember how I said the K5 Pro was like a lean soccer player with some muscle?

Yeah, forget I said that.

The K9 Pro makes the K5 Pro look like an anorexic runner on a diet of Rice Cakes and Powerade.

This thing should have its own area code. I mean, it has everything else.

Opening the box was almost like that scene in Pulp Fiction when Vincent opened the stolen briefcase.

“Are we happy? Vincent?”

“Oh, we’re happy.”

Jokes aside, the unit is incredibly robust. All connections are solid, it’s built like a tank, and you can tell a lot of care went into the project.

FiiO K9 Pro Review

Make no mistake, this is a beautifully elegant unit but doesn’t unnecessarily draw attention to itself (I know, it’s hard to believe).

As much as I just joked about it, it’s sleek, utilitarian, and unassuming.

On the bottom are 4 built-in rubber feet which are to be expected at this price point. Everything about it feels premium and high-class.

Update: The ESS version comes with separate rubber feet that stick on.

The amp does occupy a rather large footprint, so plan your space accordingly.

This all-aluminum anodized black chassis has been finely sandblasted and does look and feel rather luxurious

I was truly impressed with the craftsmanship here and there’s not a doubt in my mind you will be as well.

Before we get into sound, let’s take a look at everything it can do.


FiiO K9 Pro Review


Note: From here on out, the review will focus on the AKM version with a comparison to the ESS one towards the end.

The K9 Pro is equipped with the AK4499 DAC Chip, supports up to 384kHz and native DSD256, and utilizes the THX AAA 788+ module which supposedly provides exemplary detail and dynamics according to FiiO.

Fully Differential Design

Without getting overly technical, the main purpose of a fully differential amplifier is to suppress noise.

In short, you can expect the following benefits from a fully differential amplifier such as the one utilized in the K9 Pro:

Improved voltage swing

Both signals are out of phase, and the dynamic range is two times more than a single-ended output with the same voltage swing.

Noise immunity

Since a differential signal is a difference between two single-ended signals that are out of phase to each other, any common-mode disturbance, power-supply noise, ground disturbance, or electromagnetic interference will affect both signals equally – and ideally cancel each other out.

Reduced harmonic distortion

Theoretical analysis of the distortion products of the differential output signal results in an even-order term cancellation.

In reality, the distortion is also strongly dependent on the board layout and measurement setup.

These sentiments are echoed by FiiO themselves:

“Fully differential signals go through the four-channel DAC, four-channel volume adjustment, and four-channel amp for a truly balanced design. Such a design ensures minimal interference between different components in order to fully maintain all details and large dynamic swings in music for unmatched sound quality.”FiiO

Gold Planar GL2000 Review

While I think most of the selling points on FiiO’s website can be boiled down to “It’s clean”, I do think its Asynchronous nature is important even though you may or may not actually hear a difference.

I like to say that I can perceive a subtle one, but your mileage may vary.

The K9 Pro also utilizes what’s known as dual-mode clock management technology.

Dual femtosecond clocks of excellence

The newest generation of XMOS chips supports dual-mode clock management technology. Under USB and Bluetooth decoding, dual asynchronous femtosecond clocks are used, while under optical and coaxial decoding, automatic PLL clocks are employed. A more precise clock management system makes it easier to handle any kind of source and maintain the maximum quality possible. FiiO

Front Panel

The all-aluminum alloy front contains 3 different headphone outputs including 4-pin XLR, Balanced 4.4mm, and 1/4″ (6.35mm) Single-ended.

In the middle is your enormous Stainless Steel Volume knob that makes the K5 Pro’s look like something you’d find in Toys-R-Us.

It feels pretty incredible to the touch, and as much as I joke about audiophiles and their obsession with gear, this thing kind of almost puts me squarely back into that camp. Almost.

RGB indicator lights surround the volume knob and vary in color depending on the sample rate.

  • Blue = 44.1kHz
  • Yellow = Anything over 48kHz
  • Green = DSD

When the unit is idle, the colors will cycle.

For instance,

pressing pause initiates these color changes and they range from Green, Red, Yellow, White, Cyan, Blue, Magenta, etc.

The metal input switches and input buttons are super easy and intuitive to use as well, as you can go from listening on speakers like the PreSonus Eris e3.5s back to headphones quickly and easily depending on what you’re pairing with the unit.

The input button cycles through 5 modes: USB, Optical, Coax, Line, and Bluetooth.

Rounding out the rest of the front panel is a power button, a gain stage switch (High, Medium, Low), and the output switch (DAC, Preamp, Headphones).

FiiO K9 Pro Review

Back Panel

Firstly there’s the AC 110-115V~/220-230V~ power jack and the I/O switch on the left.

FiiO even provides a gigantic orange WARNING sign for users in different countries as using the wrong voltage input with your local nominal voltage may cause damage to the unit.

Select 115V if you are in the following countries:

USA, Japan, Canada, Mexico, Columbia, Guam, Jamaica, etc.

Select 230V if you are in China, South Korea, Russia, UK, Argentina, France, Germany, India, Malaysia, Singapore, Australia, etc.

The switch is located on the underside of the unit towards the back right.

Digital Inputs

To the right of the power switch and jack is the digital input section.

FiiO K9 Pro Review

Here we have Bluetooth, Coaxial, USB Type-B, and an Optical input.

In the box is the supplied Bluetooth Antenna. Just screw it on, pair the unit in your phone’s Bluetooth settings, and you’re good to go with your choice of headphones or active (powered) speakers. 


I used the Zen Blue for comparison with speakers, and it starts cutting out after about 30 feet. Contrast this with the K9 Pro which begins to lose signal at about 22 feet.

I tested this by walking outside of my apt. and leaving the door open.

FiiO K9 Pro Review

FiiO Control App

Another feature FiiO offers is the Control App, which was a bit persnickety to get up and running but works pretty well all things considered.

This isn’t what you’ll primarily be buying the K9 Pro for, obviously, but I suppose it’s a cool little add-on.

With it, you can adjust various settings including filters, status indicators, EQ, and channel balance.

FiiO K9 Pro Review

FiiO K9 Pro ReviewFiiO K9 Pro Review

Analog Section

To the right of the digital input section is the Analog section.

Here we have a 4.4mm line-in, RCA line inputs, RCA line outputs, and XLR balanced outputs.

FiiO K9 Pro Review


FiiO products provide great value due to the amount of options you have. With the K9 Pro, you can hook up to almost anything in a home studio/theater space.

In addition to your primary Type-B and Type-C inputs, the K9 Pro affords you a plethora of other options as well:

With its coaxial input, you’re able to connect to things like TVs, CD Players, and generally anything that outputs coax. The optical input is great for console gaming with my PS4 and even works with my older Playstation 3.

With its RCA outputs, you can use the K9 Pro as a preamp into separate speakers like the Presonus Eris e3.5, or hook up to a separate headphone amplifier of your choosing.

The 4.4mm input allows you to connect to another DAC that has a balanced output(s).

The RCA inputs allow you to use a separate DAC, and you even have the option of connecting a turntable as long as it has RCA males. A lot of USB turntables like my Audio Technica AT-LP60 are great for listening to vinyl with the K9 Pro.

If you need help with a specific type of setup, just leave a comment below or contact me!

FiiO K9 Pro Review

While we’re on the subject of headphone inputs, let’s discuss the K9 Pro’s sound.


FiiO K9 Pro Review

You may notice the Potentiometer seems to take a bit of turning to get the volume loud enough, but upon further research, this is due to its ADC Curve reconstruction.

Let’s take a look at some more of FiiO’s literature:

Adjusting the volume may look like a simple concept, but a good execution of it is crucial to an excellent audio experience. The ADC curve reconstruction method of volume adjustment used in the K9 Pro effectively minimizes any left-right channel volume imbalance and noise. It also results in a smooth change of volume across all levels. This attention paid to the simple process of volume adjustment is just another layer to making sure you truly savor your music with the K9 Pro. FiiO

Normally I’d say this is marketing-speak, but in testing for myself at very low volumes I found there to be virtually no channel imbalance.

Raising the volume is also rather smooth and fluid vs. sudden and jarring which is something you’ll come to appreciate as well – especially when switching back and forth between various Impedance/Sensitivity ratings and headphones.

The K9 Pro ensures you’re pretty much never going to be at risk of blowing your eardrums out.


make sure to turn the volume back down as a precautionary measure when switching headphones/sources regardless.

A neat feature of the K9 Pro is that it will gradually raise the volume when switching between sources or just resuming a listening session after pressing play.

This gives you time to quickly turn the volume down if you happen to goof and forget to turn it down initially.

The only other DAC I’ve tried that had this was the beloved Oppo HA-2.

Sound Profile

FiiO K9 Pro Review

The sound itself is typical AKM – not quite neutral but close enough. It’s not tube-level warm, but it never feels overly clinical or sterile sounding.

I like to think of it as a cross between neutral and warm, and given it’s advertised less than 1 Ohm output impedance, this makes sense.

Music is simply enjoyable to listen to and make no mistake, this sounds like a premium product in every facet.

I’ll still always urge you to seek out good quality source files as they are of the utmost importance, but the K9 Pro certainly delivers in terms of providing a clean backdrop for your music.

I’d feel comfortable driving anything with the K9 Pro which is yet another reason why it could be a slam dunk purchase.

To be sure,

278mW into 300 Ohm (as advertised) is plenty here and you won’t have an issue with any headphones you may have.

FiiO K9 Pro Review

K9 Pro vs. K5 Pro Comparison

The Arya sounds smooth and clean through the K9 Pro, but what’s interesting to me is going back and forth between it and the K5 Pro.

You may assume that the K5 Pro would be warmer (given its slightly higher Output Impedance), but to my ears, this isn’t the case.

The K5 Pro sounds ever so slightly more brash and… prickly for lack of a better word.

While I think the K9 Pro slightly outperforms the K5 Pro, this may have just been a placebo.

I think the K9 opts for a smoother, slightly more velvety presentation, but it also seems to highlight vocals and spacing a bit better.

Voices seem a bit more intimate, and the Soundstage generally feels more expansive.

Take these impressions with a grain of salt, as they’re simply my own interpretations and I haven’t read anything about this unit. I’m also not a huge proponent of “sound” differences in DACS, so any of the above musings are likely placebo.

FiiO K9 Pro Review

In terms of any perceived difference in sound alone, is the K9 Pro worth roughly $550 more than the K5 Pro?

In my opinion, no, but again, this isn’t why I believe the K9 Pro is a valuable unit.

If the K5 Pro was my previous do-all DAC, the K9 Pro only improves on that notion by adding even more options at your disposal.

Speaker Pairing

With the e3.5 it’s more of the same.

It may be my imagination, but I experienced a slight upgrade when switching over to balanced.

It kind of feels like the music takes on a slightly liver flavor.

Instruments and voices seem to be fleshed out a little more, with superior decay and realism.

Gaming & Film

FiiO K9 Pro Review

So, you want to use the K9 Pro for gaming and film duties.

Well, it’s got you covered, but I’ll be honest; As with the K5 Pro, this is not a unit you’ll want to be frequently moving around too much.

To test it out with my PS4, I had to remove 2 balanced cables, the RCA cables, the USB cable, and the power jack from the unit.

You then have to carry it to where your PS4 is, reconnect the USB cable, Power cable, and finally, run an optical cable from the back of the console into the K9 Pro.

Make sure to switch the input to optical and flick the switch on the front to “HP” (Headphones).

In short, if I were you, I’d plan to keep this unit in one spot.

What I do love is how it sounds with gaming and film.

I’m not going to sit here and yammer on and on about how it’s light-years better than a G6 or K5 Pro because it’s not.

It’s simply another way out of the many you can utilize this unit to do basically whatever you want and that’s why it’s so valuable.

Vinyl Listening

  • Connection: Line
  • Album: John Coltrane – A Love Supreme (1964)

Speaking of doing whatever you want, you can even use the K9 Pro with a USB turntable as mentioned earlier.

Just connect the RCA males from the record player to the back of the K9’s Female inputs, and then Run RCA to RCA from the outputs of the K9 into the inputs of your speakers.

Again, I’m using the e3.5s and AT LP60 from Audio Technica.

K9 Pro AKM version vs. ESS version

I received the ESS version in the mail and have to say I prefer it a bit over the AKM version.

If you’re a regular reader or subscriber, this won’t surprise you much as I’ve preferred the ESS chip dating back to around 2017-2018.

I’ve always perceived the ESS chip to be one of the only true differences I’ve ever heard when comparing it to other chips, but again, the “crisper”, “brighter”, more “lively” sound that I’ve discussed in the past is likely a placebo.

Aside from that,

the physical stature of both the AKM and ESS versions are identical aside from one small efficiency change – FiiO put vents on the left side to help dissipate the heat that emanates from the DAC.

K9 Pro vs. Neo

I was excited about iFi’s Neo iDSD when it came out (Value/Versatility), and both units are incredibly similar.

Both are priced similarly, both have XLR outputs, RCA Outputs, Coaxial In, Optical In, USB Type-B, and Bluetooth.

Both also have 4.4mm and 6.35mm headphone connections on the front.

Both can be used with Tidal MQA, both support DSD and hi-res files although the Neo can play up to 768kHz and DSD512 while the K9 is only capable of 384 and 256.

The K9 Pro adds RCA inputs and a balanced XLR connection for your headphones.

It’s also heftier and seems built better than the Neo.

Sound-wise, the Neo utilized the Burr-Brown chip which iFi isn’t using anymore, but they’re both pretty similar sounding at the end of the day.

The Neo may have a slightly warmer tilt to it, but the discrepancy is rather subtle.

It’s obvious FiiO’s looking to compete with iFi in this particular segment of the DAC market, and I think they have a better overall product and a slight edge here at the end of the day.

Closing Thoughts

FiiO K9 Pro Review

Since writing this K9 Pro AKM Review, FiiO came out with an ESS version (discussed above) and now a “K9” (non-pro) version exists.

The question becomes, “Is the K9 a better value than the Pro version?”

K9 vs. K9 Pro

Both have ESS chips, but the K9 Pro’s is a 9038 vs. the K9’s 9068. The K9 is lighter at 2660g, doesn’t have a Type-C port, has 3 filters vs. 7, and has the PEQ feature. The K9 Pro ESS doesn’t.

The K9 doesn’t have an MQA renderer, so if you’re looking for that, you may go with the K9 Pro or something cheaper like the K7.

The K9 supports up to 768kHz/32-Bit, and DSD512, while the K9 Pro supports 384kHz/32-Bit/DSD256.

The K9 Pro’s signal-to-noise ratio is a bit better: 129dB vs. 124.

Outside of that, the units are eerily similar, and as of now, I’m not recommending the K9 Pro anymore. I’d rather you save a bunch of money like Geico and go with the regular K9. I promise you won’t lose sleep over the decision.

Learn More:


Video Discussion (AKM Version)

Don’t forget to leave me some love and subscribe! <3

ESS Video

Here’s the updated ESS version!

Well, that’s about it for today my friend! I hope you’ve enjoyed this FiiO K9 Pro ESS and AKM Review.

Questions? Comments? Requests? Did I miss the mark on something? Please let me know down below or Contact me!!

If you love what I do here and want to support the blog and channel in a more personal way, check me out on Patreon and discover all the value I have to offer you.

Is the K9 Pro worth a purchase? I would love to hear from you. Until next time…

All the best and God bless,





Can’t decide which headphones to purchase? Interested in a complete buyers guide outlining over 40 of the best options on the market? Click on over to the best audiophile headphones to learn more!!


  • Form Factor: Table Top
  • Converter Type: D/A
  • Number of Channels: 2
  • Conversion Formats: S/PDIF (Coaxial), S/PDIF (Optical), TOSLINK
  • Converter Circuitry: A/D Chipset:
    1 x AKM AK4499
    1 x XMOS XUF208
  • Display: None
  • Max Sample Rate/Resolution: 384kHz / 32-Bit (DSD256)

Analog Audio I/O

  • 2 x RCA Coaxial Unbalanced Line Input
  • 1 x 4.4 mm TRS Balanced Line Input
  • 2 x XLR 3-Pin Balanced Line Output
  • 1 x 1/4″ TRS Unbalanced Headphone Output (Front Panel)
  • 1 x XLR 4-Pin Balanced Headphone Output (Front Panel)
  • 1 x 4.4 mm TRS Balanced Headphone Output (Front Panel)

Digital Audio I/O

  • 1 x RCA Coaxial S/PDIF Input
  • 1 x TOSLINK Optical S/PDIF Input


  • Host Connection / USB: 1 x USB Type-B
  • USB (Non-Host): 1 x USB Type-C
  • Wireless Connectivity: Bluetooth (Audio Streaming, Mobile App)


  • Frequency Response: 20 Hz to 20 kHz

Max Output Level

  • XLR Line Outputs:
    +5 Vrms
  • RCA Line Outputs:
    +2.5 Vrms
  • 1/4″ Headphone Outputs:
    +26 V p-p
  • 4.4 mm Balanced Headphone Outputs:
    +51 V p-p
  • XLR Balanced Headphone Outputs:
    +51 V p-p

Headphone Output Power & Output Impedance

  • 1/4″: 1.1 W into 16 Ohms
  • 1/4″: 2 W into 32 Ohms
  • 1/4″: 278 mW into 300 Ohms
  • XLR 4-Pin: 1.1 W into 16 Ohms
  • XLR 4-Pin: 2 W into 32 Ohms
  • XLR 4-Pin: 278 mW into 300 Ohms
  • 4.4 mm: 1.1 W into 16 Ohms
  • 4.4 mm: 2 W into 32 Ohms
  • 4.4 mm: 1.1 W into 300 Ohms
  • Output Impedance: < 1 Ohms (32-Ohm Load)


  • RCA Line Outputs:
    ≥ 123 dB (A-Weighted)
  • XLR Line Outputs:
    ≥ 128 dB (A-Weighted)
  • 1/4″ Headphone Outputs:
    ≥ 123 dB (A-Weighted)
  • XLR Balanced Headphone Outputs:
    ≥ 123 dB (A-Weighted)
  • 4.4 mm Balanced Headphone Outputs:
    ≥ 123 dB (A-Weighted)


  • RCA Line Outputs:
    < 0.0007%
    XLR Line Outputs:
    < 0.0004%
    1/4″ Headphone Outputs:
    XLR Balanced Headphone Outputs:
    < 0.0004%
    4.4 mm Balanced Headphone Outputs:
    < 0.0004%


  • RCA Analog/Line Outputs:
    ≥ 110 dB (1 kHz, 10 kHz)
  • XLR Analog/Line:
    ≥ 123 dB (1 kHz, 10 kHz)
  • 1/4″ Analog/Headphone Outputs:
    ≥ 75 dB (1 kHz, 32-Ohm Load)
  • XLR Analog/Balanced Headphone Outputs:
    ≥ 114 dB (1 kHz)
  • 4.4 mm Analog/Balanced Headphone Outputs:
    ≥ 114 dB (1 kHz)

Digital Audio

Sample Rates

  • TOSLINK Optical S/PDIF Inputs:
    Up to 96 kHz
  • Coaxial S/PDIF Inputs:
    Up to 192 kHz
  • USB Inputs:
    Up to 384 kHz (DSD)
  • Bit Depth: Up to 32-bit
  • Digital Audio Decoding: DSD


  • Power Requirements: AC Input
  • AC Input Power: 110 to 230 VAC, 50/60 Hz


  • Dimensions: 8.9 x 7.9 x 3″ / 22.5 x 20 x 7.6 cm
  • Weight: 6.2 lb / 2.8 kg

Packaging Info

  • Package Weight: 9.465 lbs.
  • Box Dimensions (LxWxH): 14.1 x 13 x 6.2″

Photo Gallery


Apollo Brown, Stalley – Blacklight (2021)

Big K.R.I.T. – 4eva Is A Mighty Long Time (2017)

Gleemer – Down Through (2020)

The Roots – Illadelph Halflife (1996)

John Coltrane – A Love Supreme (1964)

Khrysis – Khrysis On The Boards (2015)

Oh Wonder – 22 Break (2021)

Arrival (2016)

Jacob’s Ladder (1990)

What’s Eating Gilbert Grape (1993)

Se7en (1995)

War of the Worlds (1953)

The Machinist (2004)

Black Swan (2010)

The Outer Worlds (2019)

FiiO K9 Pro









  • Plenty of power
  • Incredible build
  • Extremely versatile


  • None

Don't forget to share if you found it helpful!

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Joel February 2, 2022 - 6:58 am

Can you add a comparison with popular stacks like smsl su9/su8 or topping a90/d90 E50/L50 or some other in the same price range?

Stuart Charles Black February 2, 2022 - 7:08 pm

Hey man! Yeah, I will definitely keep it in mind for the future! Would make for a nice shootout. Thanks for stopping by!

Dorian February 7, 2022 - 5:49 pm

Did bought fiio k9.
It is very good dac/amp
Sound stage is wide and 3D
Female Voices sound marvelous.
It is not hi-fi dac/amp
Just Play track 6 “Presto” Four Seasons Vivaldi.
Then go to the Filharmony and listen the same ” track ” in real.
K9 pro just makes that Violin attack soft and delicate.
It doesn’t sound right


Stuart Charles Black February 11, 2022 - 3:34 pm

Ok man, if you say so 🙂

Jenna Chaplin February 23, 2022 - 11:18 pm

I just got the K9, and your review was very influential in my decision. I pleased to say that I loved it immediately; the sound is very clear and natural which is just what I was looking for – even over BT with my iPhone 12. I’m just using it as a DAC into my amplifier (a perhaps outdated Arcam AV350) but it’s noticeably better than anything else I’ve tried. Thank you.

Stuart Charles Black February 24, 2022 - 5:13 pm

Thank you for the vote of confidence Jenna and you’re welcome! I’m so glad you’re enjoying it. I think you’ll love the features and all it has to offer. A truly great value!

Jenna Chaplin March 5, 2022 - 12:57 pm

Hi Stuart,
Very unfortunately, because I like the sound of this DAC, it looks like I’m going to return it because after using it for 10 days at approx 1 hour per day I suddenly started experiencing ‘drop-outs’ (about 1 second of total silence) in the middle of a track. It happened yesterday at least 3 times during the first movement of Rach 3 and then again today during Lief Ove Andnes’s Mozart 20. Before I commit to returning it, I’m wondering if you’ve any suggestions or if there is a solution out there? I connected it to my Mac and it showed that I do have the latest firmware 1.13.

Stuart Charles Black March 6, 2022 - 2:49 pm

Hey Jenna!

I would reach out to FiiO and get a replacement unit as you may have gotten a lemon or perhaps it just needs a driver/firmware update. That seems to fix all of the issues I’ve had with their products.

Jenna Chaplin March 5, 2022 - 1:09 pm

…and I meant to add that this first happened with a wired optical connection and then later it also happened over bluetooth – which I would not be too suprised at, but would, at this price (CAD$1250 inc tax), find unacceptable.

Stuart Charles Black March 6, 2022 - 2:50 pm

Yeah, it could just be driver/firmware. I’ve had some strange issues with some of their stuff and that’s always fixed it immediately. In fact, I was having an issue with the K9 and my speakers (buzzing/static, etc.) and an update did the trick.

Jenna Chaplin March 5, 2022 - 1:27 pm

Sorry, it’s me again. I tried to subscribe but every time I try to confirm and do the Captcha I get this

“We couldn’t process your request at this time. Please try again later. If you are seeing this message repeatedly, please contact Support with the following information:”

Stuart Charles Black March 6, 2022 - 2:50 pm

Hey! What did you try to subscribe to?

Jenna Chaplin March 6, 2022 - 4:59 pm

Hi Stuart, thanks for your helpful replies. I actually decided to exchange it at the store for the Cambridge Audio CXA81 (quite a bit of extra $) as I had been thinking of doing that originally (replacing my old Arcam AV350 which I liked) but then I found the K9 and really wanted to try it. I guess I was just unlucky with my unit as I wanted to hold on to my Arcam. I would have liked the DacMagic 200M but they are nowhere to be found other than by wating for 2 – 3 months.
To subscribe to your ‘in-depth content’ I just used the link at the bottom right of this page – directly right of where I’m typing. I got the email asking me confirm, clicked on the link. I’d still like to do that when the link works.

Stuart Charles Black March 7, 2022 - 9:45 pm

Thank you for bringing that to my attention. Seems the form is not working. I will fix it and let you know.

Sorry to hear it didn’t work out with the K9 but keep me posted on your impressions of the CXA81. I really do enjoy Cambridge products (the ones I’ve had experience with).

Stuart Charles Black March 7, 2022 - 10:30 pm


I just fixed it, did a test subscription with one of my emails and it worked. Can you clear your cookies/cache on your browser, try again and let me know if it goes through? Should say “Thank you, your sign-up request was successful! Please check your email inbox to confirm.” Also you can try other browsers as well. If it does go through, check your spam folder if you don’t see it in the main one. Thank you! 🙂

Jenna Chaplin March 14, 2022 - 6:47 pm

Website won’t let me post; keeps displaying same screen

Stuart Charles Black March 14, 2022 - 7:14 pm

Hey not sure what that’s about but the comments go through just fine. No worries. Yours came up 5 times lol. I generally just delete the duplicates as I get them quite frequently. It’s not a big deal on my end but I’m sure it’s confusing on yours. I don’t know what causes this.

Jenna Chaplin March 14, 2022 - 6:49 pm

Is there a size limit? I have a full reply of the info from the failed attempt to subscribe.

Stuart Charles Black March 14, 2022 - 7:14 pm

Nah there isn’t. Just replying to this so you know it went through.

Jenna Chaplin March 14, 2022 - 6:50 pm

Seems that there is, so I can’t paste in all the diagnostic info. Oh well.

Stuart Charles Black March 14, 2022 - 7:17 pm

Ah. Thanks for trying. Gonna have to figure out what’s going on.

Jenna Chaplin March 14, 2022 - 10:39 pm

Sure, please manually subscribe me if that’s easier. Thank you.

Stuart Charles Black March 15, 2022 - 2:11 pm

Will do Jenna! 🙂

Jenna Chaplin March 14, 2022 - 6:49 pm

Strange indeed – Trying again..

Hi Stuart,

Everything appear to work until the very last step after I prove that I’m not human and then click subscribe. I am running Adblocker and Privacy Badger but I turned them off for this site (as otherwise I can’t post here anyway).

Server Status

We couldn’t process your request at this time. Please try again later. If you are seeing this message repeatedly, please contact Support with the following information:


date: Mon Mar 14 2022 14:34:54 GMT-0400 (Eastern Daylight Saving Time)

user agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:98.0) Gecko/20100101 Firefox/98.0

Please let me know if there is a fix for this. It’s too much trouble to keep on doing the Captcha every time before it fails.
The CXA81 just arrived this morning. It does have the more ‘forward’ character as described which contrasts with the more neutral sound of the FiiO. I’m not sure yet if I prefer it but it certainly is very good. More later perhaps. Thanks.

Stuart Charles Black March 14, 2022 - 7:15 pm

Weird. I can just manually subscribe you if that’s cool with you. Let me know 🙂

Jenna Chaplin March 16, 2022 - 8:42 pm

A quick note on the Cambridge CXA81 now that I’ve had a few days to listen to it. At first I thought it sounded a bit too ‘bright’ (we have no choice but to be subjective here but I guess you know enough to imagine what I’m describing) but now I think of it as perhaps more ‘lively’ than the FiiO. In retrospect I do feel that the FiiO was just a little too ‘smooth’ – even though I liked it a lot. The impression of the FiiO was more like that of listening to a good hi-fi system rather than listening to a ‘performance’ which is my experience of listening to the CXA81 – so now I do feel happy with my choice.

Stuart Charles Black March 16, 2022 - 9:24 pm


Interesting observations! I just had a look at the output impedance of the CXA81 and it’s a minuscule 0.1 or thereabouts so your “bright” impressions line right up.

I personally really enjoy the super neutral variety but headphone pairings can be tricky for obvious reasons.

Jenna Chaplin March 16, 2022 - 8:42 pm

Hmm, that last comment isn’t showing but I’ll not repeat it as I’m guessing you can see it but I can’t.

Stuart Charles Black March 16, 2022 - 9:25 pm

Yeah, I have to approve them first so after commenting I’d generally give it anywhere from a few hours to a day depending on if I’m in the office or not.

Jenna Chaplin March 17, 2022 - 4:51 pm

Thanks Stuart. I have the B&W P9’s which I’m very happy with. I’ve just always only had B&W speakers so stuck with them for my headphone choice. Thanks to your articles on audiophiles and marketing I’ve now let go of the (always unnecessary!) embarrassment I used to feel for still owning my 40-year old B&W DM7 Mk2’s. I know the bass extension is perhaps their weak point but the way I have them set up in my room seems to take care of that well enough. I also have the Audioquest Dragonfly Cobalt (yes, I know… could have gone with the Red but was persuaded by reviews!) and like that too.

Stuart Charles Black March 19, 2022 - 3:04 pm


My Dad still has his B&W speakers from the ’90s and they sound incredible – always have. I actually really enjoyed the P9 though it gets some hate around the internet and I don’t really know why. The P7 sounded God awful but the P9 was definitely better.

You will be interested to know that Apos reached out about the new ESS version of the K9 Pro which they are sending over for demo. It uses the Sabre chip (vs. the AKM in this article) so will be much more in line with your preferences. I will keep you posted.

Jenna Chaplin March 19, 2022 - 5:50 pm

Thank you, Stuart, I’d still be interested in a K9 Pro – as a headphone amp plugged into my bedroom where I do my headphone listening. Look forward to hearing more.

Stuart Charles Black March 21, 2022 - 4:10 pm

Welcome! 🙂

Jenna Chaplin August 29, 2022 - 2:31 pm

Hi Stuart, hope you are well. I finally found some space in my budget (cramped by house repairs unfortunately) and got the ESS version last week. So far (fingers x’d) there haven’t been any glitches or drop outs and I really do like it. It’s surprising, and I do feel that this isn’t my imagination, that it does sound a little different from the AKM, at least as far as my sonic memory can be trusted, which I feel it can, but that’s purely subjective of course. It seems to have a little more presence and vitality; even if the difference is subtle. I’m not looking for any new equipment at the moment but I’ll be back here to read your articles and guides whenever that is. Keep up the good work.

Stuart Charles Black August 29, 2022 - 3:36 pm

Thank you for the nice comment!

Do keep me posted on your impressions. It’s not your imagination. I too think it sounds a bit more neutral/sterile and I’ve always said this about the ESS Chip. To me, it represents pretty much the ONLY stark contrast vs. other DAC chips, meaning there is a pretty obvious audible difference. That said, most other differences between various products are incredibly subtle and inconsequential.

sonu March 29, 2022 - 3:04 pm

Today I was searching some blogs on Google and when I went to someone’s site and saw and read their blogs, I did not like anything and when I came to your site and saw your site, I liked your site very much.

Stuart Charles Black March 29, 2022 - 7:28 pm

Thank you, Sonu!

Mac August 18, 2022 - 5:06 am

Hey Stu, Just got K9 Pro ESS yesterday! It seems to bring out the best in everything. I am running 4 Dali Spector 2 speakers off an older Marantz SR5009, it sounds like I got a new sound system. The K371 sounds awesome, between the burn in, dekoni earpads and the K9 they have a lovely sound stage for a closed back and are a lot of fun, still no $100 headphone moments. I highly recommend the track Freefall By Cornelius through them. The K702 are stellar, I just finished a crazy burn in on them and the K9 Pro is just hitting all the sweet spots. People listen to the man and buy the DAC you won’t regret it. As always Stu thanks for the audio wisdom! ???

Stuart Charles Black August 21, 2022 - 4:06 pm

Thanks, Mac! So glad you’re enjoying it. 🙂 I love the K9 Pro for its versatility and ability to pretty much connect to anything. It really is a great all-in-one DAC.

Jenna Chaplin August 29, 2022 - 3:03 pm

Still unable to subscribe – turned my VPN but that didn’t do it…

We couldn’t process your request at this time. Please try again later. If you are seeing this message repeatedly, please contact Support with the following information:

Stuart Charles Black August 29, 2022 - 3:34 pm


I manually added you until I get whatever this is sorted out. 🙂 Thank you for the heads up.

Jenna Chaplin August 29, 2022 - 6:28 pm

Thank you for the subscription update, Stuart. I just wanted to add something about Type C USB connections. I have a MacBook Air and connected it to the K9 with a USB-C cable and it worked perfectly straightaway. No drivers to download. Note that the Mac will only show it as an audio output option if the K9 is turned on and set to USB input. I decided to try this as my kitchen microwave near my WFH zone often interferes with Bluetooth. And, I just tried listening to the ’96 remaster of ‘Money for Nothing’ by the Dire Straits (it was mentioned in another DAC article I was reading) and at 1:36 when the main riff comes in (listening on my P9s and volume up a bit), it literally made my hair stand on end, it was absolutely electrifying. I don’t think I’ll ever regret buying the K9.

Stuart Charles Black August 30, 2022 - 8:19 pm

Nice! So glad to hear it. How do you like the P9? It’s been a while since I heard that song; I’m going to have to fire it up!! I can play Sultans of Swing which is one of the most fun on guitar.

Jenna Chaplin August 31, 2022 - 2:23 pm

I like the P9 a lot although I sometimes wish I’d compared them to comparably-priced Sennheisers as I got them as a replacement for my old Senn RS 220 (wireless) but the wireless performance was really awful (dropouts) – even in direct line of sight at less than 10 feet, and it was so annoying that it (illogically) put me off buying a wired pair of Senn’s. In hindsight I remember the actual sound of the Senn’s as having more presence and clarity than the P9, but it was just one of those ‘gotta have it’ moments I think and so I bought the P9 after listening to them only. However, I like them well enough and I’d only likely consider replacing them when I’ve paid for the new steel roof for my house which will be a couple of years! But, to the P9’s sound: as far as I can tell, the soundstage is an accurate rendition of the intention of the recording engineers as – especially with classical music – I can sense where I’m supposed to imagine that I’m sitting – although it’s clear that these recordings are intended for listening to on speakers. The overall sound is very detailed with just a touch of ‘warmth’ I think, which perhaps some would not like. The Dire Straits track certainly shows that they can ‘kick’ when needed. Yes, Sultans is a real classic and a lot of fun I’m sure.
Something interesting about the K9’s bluetooth: it appears to be a bit of a ‘bully’ as I noticed that while I had left my MacBook transmitting to my Audioengine speakers, when I turned the K9 on upstairs it replaced the connection from the MacBook though I had paired it with my iPhone right beside it, which seemed kind of odd. So I deleted it from the Mac and only connect to it with the iPhone, which was the original intention anyway. The BT connectivity so far has been perfect; it just always connects immediately which is a nice change!

Stuart Charles Black September 4, 2022 - 2:46 pm

Yeah, I really liked the P9 but hated the P7. I thought they were radically different actually. The P7 seemed bloated, hazy, and just really bad sounding while the P9 was crisp, open, airy, and very well done IMO.

I think all of what you said mimics my experience with the P9. It’s just a great product although I do think it’s a bit overpriced.

Jenna Chaplin September 13, 2022 - 11:37 am

Hi Stuart. Recently, having got a Tidal Hifi+ subscription, I’ve been listening on my iPhone, via USB camera adaptor and the supplied USB cable for the K9 – and something is definitely wrong…. almost on any track with a slow fade out, and usually (quite precisely), at around 13 seconds before the end of the track, the music cuts out very briefly twice and then maybe a third time another second later. I’m going to write to FiiO about this but I’m just wondering if you’ve heard of this before or would be interested in testing to see if your K9 does this too. It’s so annoying that I went back to the BT connection but with iPhone all you get is AAC. I’m going to see if there is a noticeable difference between USB and BT, and I realize that it may be too subtle, but I do want to get the quality of sound that I’m paying for. My suspicion is that the K9 is somehow tricked by the gradual level decrease into acting as if the track has ended while the level is still fading. It doesn’t happen over BT so that would appear to rule out the iPhone as the cause, but perhaps not necessarily? I will write to Tidal too, they are very responsive. I will also do some more testing.

Stuart Charles Black September 14, 2022 - 2:09 am


This is actually a Tidal issue and something I experienced back when I still had a paid Hi-Fi subscription with them. Very annoying to the point where I almost canceled right then and there. It would happen on and off for hours at a time and really didn’t go away throughout the duration of my listening sessions. I eventually got rid of mine for a few reasons (that one included), but I’d def reach out to them about it as I am pretty certain not a K9 Pro issue.

Keep me posted!

Jenna Chaplin September 14, 2022 - 4:34 pm

Hi Stuart, thanks for the response. I just tried exactly the same tracks and USB connection with my Dragonfly Cobalt and it does not happen – which implies that it’s not a Tidal issue. It doesn’t happen when I connect my MacBook Air directly to the K9 by USB-C. Aha, after another test, it seems to be related to MQA only, when I used the same USB config mentioned , playing the HI-FI version rather than the ‘master’, it does not cut out near the end. What I suspect may solve the problem is using the Fiio LT-LT1 connector (mentioned on their support page, but which seems impossible to find at a reasonable total cost) or a similar USB-C DAC OTG cable that I found on amazon.com. When I get the OTG cable (expected for 9/22), I will let you know. Other than that, my experience with Tidal has been excellent so I guess they’ve ironed out those issues you had. One other thing – I don’t have any MQA files in my personal library, they are all FLAC so I can’t test it using MQA files that are not from Tidal. If anything useful comes from FiiO support, I’ll let you know.

Stuart Charles Black September 15, 2022 - 3:23 pm

My pleasure, Jenna! Keep me posted 🙂

Jenna Chaplin September 16, 2022 - 3:00 pm

Hi Stuart, FiiO don’t seem to have a solution for this, and I saw that at least one other person has almost exactly the same issue on head-fi.org. They have forwarded my issue to their engineers but are quite honest that I should not expect a solution in the immediate future. The new USB-C DAC OTG cable does not fix the issue, which was no surprise. However, the simple solution is to switch from Master to Hi-Fi since the issue does not occur with a Hi-Fi stream. Now, connected by cable to the K9, I see a yellow light which, probably, indicates 96/24 which I’m prefectly happy with. So, I’m just simply downgrading my Tidal subscription to Hi-Fi, which is prefectly good enough for my equipment and ears, and saving a few $ at the same time. If FiiO ever do come up with a solution, I’ll let you know. Your helpful engagement has been much appreciated.

Stuart Charles Black September 16, 2022 - 3:12 pm

No problem Jenna! I think what you just said would indicate it’s a Tidal issue if it doesn’t happen when switching from Master to Hi-Fi. I had the same exact problem with Master files and it was due to a Tidal error, not the DAC or anything else. Just my thoughts.

Jenna Chaplin September 17, 2022 - 11:24 am

But, when I switch the K9 for a Dragonfly Cobalt, keeping everything else the same, the problem disappears. Perhaps, though, there is something in the Tidal data stream that causes the fault in the K9 that does not affect the Cobalt, and it’s possible for Tidal to fix it, the difference being in the DAC’s MQA handling and not really a K9 fault or error? Well, I’ve written to everyone else so now it’s time to see what Tidal have to say.

Stuart Charles Black September 19, 2022 - 2:42 pm

Could be. Hard to say either way but yeah, I def had issues with Masters specifically. Keep me posted!

Jenna December 6, 2022 - 1:31 pm

Hi Stuart, hope you are well. Tidal finally got some info from FiiO and it appears (?) that they are aware of ‘an issue’ and that there may be a firmware fix for it at some unknown time in the future.. However, the simple solution was to revert back to HiFi on Tidal (reducing my subscription by 50%) where (of course) I discover that there is no clearly discernible difference between MQA and 44.1/16 using my P9’s, or at least any difference is so minute as to not impact the listening experience. Basically, since I don’t care about MQA, this is not an issue for me any more. The K9 works fine now and I can just listen to the music, which is the whole point.

Stuart Charles Black December 7, 2022 - 9:51 pm

Great to hear from you, Jenna! Wish I could make a poster of your comment and plaster it everywhere LOL.

Jenna December 27, 2022 - 7:55 pm

Hi Stuart. Happy Holidays! Good news and bad news. I actually (!!) got a response from FiiO with a link to a firmware update (from vE 21 -> vE 25). I really believed that this would work (silly me). I had to go to the trouble of using my old Windows computer because they only included an .exe file, then I paid US$10 to upgrade my Tidal to HiFi Plus (downgrading it before next billing cycle). Following all the instructions and confirming with iPhone app that the firmware was the latest, I fired up Tidal and set it to Master quality streaming but was extremely disappointed that the same random drop outs still kept on coming (not often but once per song is enough to ruin it). Replied letting them know and how displeased I was. Grrr! I’m not sure I’m up for trying this again no matter what they promise – unless they refund my wasted $.

Anyway, best wishes for the New Year.

Stuart Charles Black December 29, 2022 - 3:43 pm


Happy Holidays to you and yours as well. 🙂

I’m so sorry to hear that! This is why I dumped Tidal. I don’t think I’ve ever had a single dropout with Spotify. Tidal was a nightmare for me.

Keep me posted on everything! Hope you have a fantastic New Year and an an even better 2023.


Jenna January 1, 2023 - 2:59 pm

You’re right. I just went back to Apple Music and, big smile, I see that they have retained all of my info so it’s as if I never left. Now I have a nice yellow colour on my K9 and it sounds great. I only ever had drop-outs with MQA and I never had them with Apple before so now it’s ‘So long and thanks for all the [drop-out] ” -sh to Tidal.

Stuart Charles Black January 2, 2023 - 6:12 pm

Haha. So glad you’re Tidal-free. The app as a whole really is a pain in the ass. I too have been messing with colors but this time on the K7 in my comparison article to the K5 Pro, K3, and K9. Fun stuff!

fily December 4, 2022 - 5:18 pm

Hi Stuart,

Thank you for this detailed review. I appreciate your work!

Did you try the Fiio K7 ?
Connected to a bluetooth device like FiiO BTA30 Pro, will this be a better value?

Stuart Charles Black December 4, 2022 - 10:03 pm

Hey there! Thank you for the nice comment. I have a K7 coming in the mail so stay tuned!!!

Jenna February 10, 2023 - 6:13 pm

Hi Stuart. Just thought I’d pass this on in case you’ve heard of it elsewhere, and I’m sure it’s not my imagination. Since switching to Apple Music I am noticing, occasionally but often enough, what seem to be ‘digital audio artifacts’ in the form of very short high-pitched ‘tick’ sounds during playback from iPhone connected by USB DAC cable to the K9. I didn’t hear this with Tidal so now I’m trying Amazon to see if there’s a difference. I really do suspect that Apple are causing this. It’s noticeable enough to be an irritation. Hope you are well.

Stuart Charles Black February 10, 2023 - 6:20 pm


Thank you for the update! That’s .. disappointing. I don’t use Apple music but I was just reading that they have one of the largest selections of songs?

Jenna February 24, 2023 - 12:17 pm

Yes, that does appear to be true, which is.. disappointing. I’ve found that Amazon is missing a few (mostly obscure) albums that I had on Apple. Also, Amazon is not entirely free from these artifacts but they appear much less frequently – so it’s hard to pinpoint the cause of the problem. If I had more time and energy I would do a direct comparison with my Cobalt but am just too busy at work these days. I should check to see if you have a section on streaming services to post more on the subject. I’ve just started using Presto Music for classical music – the indexing and search is so much better than on services designed for ‘songs’. I wonder why they don’t use the word ‘tracks’ instead for all the stuff out there that doesn’t have vocals!

Stuart Charles Black February 27, 2023 - 4:20 pm


Nice to hear from you again! I actually did update my Tidal vs. Spotify post so check that out but also now that you mention Amazon music I may add that one in the comparison as I do have Prime and thus the Amazon music app on my desktop. I just never use it. If it’s anything like Prime, I’m sure their selection is likely the best. I can pretty much find any film I want to see on Prime. Me and a friend are on this obsessive 20s-50s horror kick and it’s been super fun being able to find it all.

Jenna March 5, 2023 - 1:18 pm

Hi Stuart,
Yes, I took a look at your Tidal / Spotify post and generally agree with your comments on Tidal. I really find on my K9 and P9s that 96/24 sounds better than 44/16 so that’s what I want and is why, right now, I’m comparing Apple to Amazon. Quite possibly I’m noticing the difference because 96/24 recordings are newer and made with better equipment and also the engineers know that listeners’ expectations are higher (e.g. soundstage). Unfortunately the random clicking and ticking sounds seem be just as bad on both so it could be the K9, my iPhone 14, or even my Modem (1.5 G fiberoptic). This irritates me so much that eventually I’ll have to determine where the problem lies. I only notice it on headphones but I’m sure that doesn’t mean it’s not present when playing through speakers or just that maybe it’s less noticeable; I’m not sure. But, for streaming, I listen to my speakers from iPhone via bluetooth to a CXA81 so maybe the clicks and ticks aren’t there(?) present – I’ll have to plug my phones into the amp to check. So, if you ever do some comparisions with other streaming service, I’ll be interested to hear your opinions – and especially if you experience these or other artifacts. Keep up the good work.

Stuart Charles Black March 6, 2023 - 7:52 pm


Great to hear from you! Sorry about your dilemma. I found this: https://discussions.apple.com/thread/253572740 Could be an Apple issue. Seems a lot of users are having the same problem.

Def keep me posted! I was actually about to buy an iPhone 11 as I desperately need a new phone, but now I’m not so sure haha. While we’re on the subject, what are your thoughts and opinions on Apple/iPhones in general. Do you like your phone and are you satisfied with it? The guy at the store was really gushing over them. We’re basically between the iPhone 11 and the moto stylus.

Gordei October 16, 2023 - 12:25 pm

Hey Stu! How do you think recently rolled out FiiO K9 compares to a pro version? $200-300 difference seems huge while, if I get it right, differences in sound and overall build are quite subtle per reviews and opinions.

Stuart Charles Black October 16, 2023 - 1:01 pm


Thanks for the heads up! I will have to reach out to FiiO about the unit. That said yeah, there are probably next to no differences lol. That comes from experience with over 60 of them. In any event, I will keep you posted for sure! What’s your budget like? I would definitely love to help you choose something appropriate based on your situation/needs, etc.


Gordei October 17, 2023 - 1:39 pm

Well… I’m no audiophile by any means except wanting to have good sound at my disposal. Currently using Asus STX (paired w/ AKG 551’s, going to get K712’s or HD6XX/650 or smth similar to these), which lately started struggling with some – probably software, but idk – bugs. Thought of a change and… I see either top models like K9 Pro or lower end like Creative PCI-E cards, no middle point.
What I liked about K5/7/9/Pro models is that they can be USB units, standalone, can switch between headphones and monitors using physical switch (got el cheapo Edifiers R980t now, but who knows), have physical (!) sound knob. Do I need K9? Most probably not, I might not even see the difference in sound with K5 model, lol. But at the same time I like buying myself a good stuff… Know the feeling?
Thought of getting Creative AE-9 or some Schiit DAC+Jotuhneim2, for example, but idk, one seems a bit expensive for what it is and other is nice, but quite hard to get around for fair price in Europe.
If you’ve got an idea about something that might be up for the job, I’d appreciate it!
And last but not least… All mentioned products have something in common: they’re cool looking and substantial, nice to touch and work with. Another feeling you know about 🙂

Stuart Charles Black October 20, 2023 - 10:27 pm


Oh, I know the feeling all too well. Lol. That’s why I have to kind of take a step back from it. I’m always asking myself “What is this about?” “Is it about creating and listening to music, or is it about the gear?”

I’ve actually been falling into this trap again as I get back into beatmaking. The feeling, as you mention, of acquiring new gear is awesome and kind of addicting. But I’m always reminding myself to make more music rather than obtain more stuff.

The same goes for just listening to music, and I would argue it’s even more dire because we’re not using Amps, DACS, and headphones to create anything (as in the case of production equipment). We’re simply listening. And that’s fine. But it gets to a point where diminishing returns kicks in and there’s really nowhere left to go.

The “sound” difference between a K9 and a K5 Pro is basically non-existent, and that applies to pretty much all amps and dacs. The only reason I recommend the K9 as an end-game is because it has the most features and versatility. This is something I’ve always stood by in the way that I endorse products.

Some would argue with me on the sound thing, but I just can’t justify hundreds of extra dollars spent on what amounts to a minuscule difference (if there even is one) and in 99% of cases, there is no discernible difference that you’ll be able to hear. So that is to say that I’m absolutely never telling someone to buy a dac because it “sounds” better than another one. That to me just doesn’t exist.

The problem is that reviewers and shills will tell you there are more places to go, but what they’re really doing is beckoning you down the rabbit hole and once you’re down it, you AIN’T coming back up. xD

Unless you think you’re going to need the extra features of the K9, I would go with the K5 Pro (single-ended only) or K7 for balanced.

Hope that helps!

Keep me posted on everything.


Gordei January 10, 2024 - 5:08 pm

Hey Stu!

Guess what? I didn’t listen to your advice and got myself K9 non-pro version.
Okay-okay, there’s a backstory for that. I just stepped into the great deal of having K9 for 400 euro new including shipment. K5 was about 190 euro without shipment, K7/Pro about 220/250. For that money I just figured I couldn’t lose much, but could gain some. But back to this later.

Currently using it with HD6XX and Edifier 980T I can conclude several things.
First, this thing has ton of power compared to STX. Without any hearable distortion. Got it on Mid setting and knob faces about 1 o’clock and I regulate my music/game/youtube sounds down in according apps, rarely using the knob.
Second, knob itself doesn’t feel premium or I don’t know. I expected more resistance, more grip to it. This alu thing is too sleek for my taste.
Third, initially I faced a bug when connected it to a front USB PC port: every hour or so I had sound disappearing for like 5 seconds or something. German FiiO site where I bought it suggested trying listening to offline stuff and so on, but being connected to a rear port actually resolved the issue for now. Dumb, but whatever.
Fourth, it has annoying setting of disabling volume once you stop listening to something in like few seconds. Once you resume, it has fading effect backwards. DANG! Didn’t find anywhere how to disable this thing. Wish FiiO could make timeout a bit longer or removable/possible to set up individually.
Fifth, it is a warm device and dust will get to it eventually. In my case a lot, so having it on a stand isn’t best solution. But it’s my own fault.
Sixth, mute/power off button is OK, but if I use it with my PC, I would expect it to just turn off/on once source is off/on or have separate button for that. Powering it up separately isn’t most convenient either. No big deal, but at this price level these details have to be not overlooked imo.
Seventh, switching buttons have AWESOME feeling. Nice job! Switching isn’t too fast, but I can live with that.
Eighth, case made of single piece of aluminum feels not just awesome, but GREAT. Plus as I understand it also works as a heat dissipator too.
Ninth, sound is good. Great. Excellent. I don’t know, my hearing isn’t good to hear a lot of differences between my previous STX card and this one, but it feels more stable with volume up, smooth, satisfying. Maybe I’m just making it up, but it is my current feeling. No WOW effect for sure, but I didn’t except it to be like that anyway.
Tenth, using USB connection I couldn’t change it to a higher than 44.1kHz setting for some reason. Not an issue at the moment, but something I don’t understand how do I have to deal with it.
Eleventh, USB cable is too short. Really. In 2k24 it shouldn’t be an issue…
Twelfth, I was expecting internal settings via Bluetooth to be more exhaustive, not just some basic stuff.
Thirteenth, internal PSU is awesome. Really. I hate having all the PSU’s lying behind PC and collecting dust. This thing is another point why I lusted it over K5/K7 units. Small, but important for me point.
Fourteenth and last, if units like this one have BT, I expect them to be able to connect to my BT headphones as well. Because why not? Sometimes I need to go to a kitchen and want to be connected to my PC and don’t fiddle with other hardware, simple like that.

Bottom line. Don’t get me wrong, these complaints are just some small things that irritate me, but don’t make my experience anything besides awesome. This card is great and is what I expected it to be for the most part. I will pair it later with better monitors, maybe some AKG’s as well.
P.S.: but wish FiiO would collect feedback and improve some things via software patches.

Thank you very much for great reviews, Stu!

Best regards,

Stuart Charles Black January 13, 2024 - 8:13 pm


Thanks for stopping back by! Stoked everything is cool with the unit (for the most part).

I can totally understand your frustration with the sound thing. I’m actually currently on my second EF400 unit from HIFIMAN and having a similar issue that I’m not going to go in depth in for the sake of keeping it short. I’ll just say it’s incredibly irritating and the only dac that’s having this issue out of like 18 dacs I have here. No seriously. I just went and counted them. xD

It’s weird you’re having these issues though. You said it was the K9 and not the pro version? I’m just double checking. I actually have a K9 (not pro) here that I need to review, but I haven’t had any issues with 2 other K9 Pros. They were the AKM and ESS earlier versions.

Re: the bluetooth issue, you mean, your headphones connecting directly to the unit w/o a phone? If so, I’ve noticed some other companies claim this in their manual and then it doesn’t work (i’ve even emailed reps and made it extremely clear what I’m saying, and they say it works), but that’s a whole different can of worms. I’m fine with just pausing and coming back, but I totally get what you’re saying. That would be REALLY convenient haha.

And you’re welcome man! Hope to chat again soon. Keep me posted on everything!


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