Shoutout to Sunny and the folks over at FiiO for sending over the K3!
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…
I didn’t have a FiiO K3 Review on this site (go figure) but found myself using it quite a bit lately.
Because of that, I thought I’d do an official write-up of what has proven to be somewhat of a strange animal; something that’s gotten a lot of use in recent months here in my home, but perhaps not for the reasons you may be expecting.
So strap on (I mean in), and let’s see what all the fuss is about.
At A Glance
FiiO K3
Price: Check on Amazon! | Check B&H!
In The Box
FiiO K3 Compact Headphone Amplifier and USB Type-C DAC (Black)
USB Type-C Cable
4 x Spare Foot Pads (Note: The 2 pads you don’t see are on the bottom of the unit)
Quick Start Guide
Limited 1-Year Warranty
Specs
- Capability: Up to 32-bit/384kHz.
- Stereo Crosstalk: ≥70 dB (1 kHz).
- Outputs: 1x Coaxial, Line, 1x 3.5mm headphone jack, 1x 2.5mm balanced
- DSD Support: Yes, 64/128/256.
- Output Impedance: 1.04. What is Output Impedance?
- Output Power (Single Ended): 220 mW @ 16 Ohms, 120 mW @ 32 Ohms.
- Output Power (Balanced): 320 mW @ 16 Ohms, 200 mW @ 32 Ohms.
- Output Voltage: 7.39 Vp-p.
- Digital Outputs: Coaxial: RCA for 192 kHz, Support DSD64 DOP
Optical Out: Up to 96 kHz. - Inputs: 1x Type-C USB.
- Signal-to-Noise Ratio: ≥113 dB.
- THD: ≤0.004%.
- Frequency Response: 20Hz to 80kHz.
- Op amp: 2 x OPA926.
- Low-pass filter: TI OPA1612.
- USB chip: XMOS XUF208.
- Dimensions: 2.8 x 2.3 x 0.9″ / 70.0 x 58.0 x 22.0 mm.
- Weight: 83 grams.
- Warranty: 1 year.
- Power: Bus powered, 5 VDC 500 mA.
- Features: Bass boost, Gain switch.
Sound
Back in 2019 when I first received the K3, I thought it was a nice upgrade from the E10K save for essentially one caveat:
It didn’t provide as much power out of the unbalanced jack and isn’t the ideal choice for harder-to-drive headphones.
The sound differences between them are subtle but still noticeable.
The K3 sounds a bit more refined and ever so slightly less grainy, but those differences aren’t ones you’ll likely care all that much about.
The reason is that I’m afforded the luxury of being able to discern them (the small differences) given how many DACS I have here in the studio.
Most people don’t and will never because they still have their sanity. I pretty much do not.
In addition to that,
sound differences mostly stem from the source material and your headphones, not the DAC.
Even knowing about those subtle discrepancies, ultimately I still don’t care that much and mostly recommend DACS based on features and versatility.
Fortunately for us, the K3 is very versatile and it doesn’t need a driver, especially at its current price point.
Let’s take a look.
Front Panel
A Great Desktop Setup. Pictured: E10K (Top), K3 (Below)
On the front, there’s the volume potentiometer, bass boost, gain switch, 3.5mm single-ended jack, and a 2.5mm balanced jack.
On the back panel, we’ve got a 3.5mm line out, a USB Type-C jack for use with your PC/Laptop, a Coaxial out, a USB 1.0/2.0 switch, and an optical out.
If you want to use USB 2.0, just go to FiiO Support, and download the USB DAC driver.
- Related: What is a USB DAC?
Then simply turn the unit off and disconnect everything (basically a reboot).
Now you can use USB 2.0, which supports DSD256 and up to 32-bit/384kHz.
The USB 1.0 section only supports up to 24-bit/96kHz files.
- Recommended: What Is DSD In Audio?
The power-on indicator on the K3 also doubles as a sample rate indicator.
- Blue = 44.1kHz or 48kHz.
- Yellow = Anything above 48kHz.
- Green = DSD.
Usage
Pictured: E10K (Top), K3 (Below)
As mentioned in the open, the K3 is quite versatile and gets a lot of use in my studio right now.
Let’s see what it’s capable of.
Coaxial Out
A coaxial output allows you to connect the FiiO K3 to other audio equipment, such as an external amplifier, home theater receiver, or a higher-end DAC.
This enables you to use the FiiO K3 as a source device to feed an external system with a higher-quality audio signal. Coaxial connections can transmit digital audio signals with good signal integrity.
Better Audio Quality
By connecting the FiiO K3 to a higher-end audio system through the coaxial output, you can potentially achieve better audio quality compared to using the built-in DAC and amplifier of the FiiO K3.
This is especially useful if you have high-quality headphones or speakers and want to take full advantage of their capabilities.
Versatility
Coaxial outputs are common on audio equipment, so having this on the FiiO K3 makes it more versatile and compatible with a wider range of audio setups.
Keep in mind that the benefit of using a coaxial output depends on the quality of your external audio equipment and your specific use case.
If you’re primarily using the FiiO K3 as a standalone headphone amplifier and DAC, you may not need to use the coaxial output.
However, if you want to integrate it into a more extensive audio system, it can be a valuable feature.
Optical Output
An optical output on a device like the FiiO K3 also serves a valuable purpose, similar to the coaxial output, but with some differences.
Digital Audio Transmission
An optical output also allows you to transmit digital audio signals from the FiiO K3 to other audio equipment, such as an external DAC, AV receiver, or soundbar.
Optical connections use light to carry the signal, providing electrical isolation and resistance to interference, which can lead to cleaner audio signals.
Compatibility
Optical connections are commonly found on various audio equipment, making the FiiO K3 more versatile and compatible with a wide range of devices.
This can be particularly useful if you have an external DAC or home theater system that accepts optical input.
Flexibility
Using the optical output can be beneficial if you want to integrate the FiiO K3 into a multi-component audio system.
It allows you to take advantage of the FiiO K3’s DAC and amplification capabilities while still benefiting from the higher-quality processing or amplification capabilities of other devices in your setup.
Enhanced Audio Quality
If you have an external DAC that is of higher quality than the internal DAC of the FiiO K3, you can use the optical output to route the audio signal to the external DAC for improved sound quality.
This is especially valuable for snobby audiophiles who demand the best audio performance.
EMI/RFI Isolation
Optical connections are immune to electromagnetic interference (EMI) and radio-frequency interference (RFI).
This can be crucial in scenarios where there may be a lot of electronic noise, as it ensures that the audio signal remains clean and free from interference.
Example
With optical or coax out, you can hook it up to something like a receiver or speakers that have optical in or coax in.
A good example would be something like the Edifier R1280DB Powered Bluetooth Speakers which have both an optical input and a coaxial input.
Line Out
Right now, the line-out function is getting quite a bit of use for me.
Though I don’t really use the K3 with headphones anymore (unless someone requests a demo), I have been using it full-time with my Presonus Eris e3.5s which are really versatile and incredibly affordable.
Just snag an RCA to mini cable and you’re set!
With this setup, I’ve got plenty of headroom and haven’t even turned the volume up to 11 yet. xD
I’ve even used e3.5 balanced with the K9 Pro via female XLR to TRS male (2 cables required) as the e3.5 has balanced inputs.
In any event, the K3 is really versatile.
You could also use the line out to a separate, more powerful amplifier later down the road as it can be just a DAC if you so choose.
Update:
I’m not sure if this is an issue with the K3, but a couple of times music will just stop playing and the sound will randomly re-route to another DAC in the sound panel (in this case, the Zen hooked up to the ATOM Hevi).
So basically, the K3 disappears in the sound panel and I have to turn it off and on again.
I have since had no issues, but I thought it was strange. The DAC is 4+ years old now FWIW.
With your phone
The K3 can technically be used with a smartphone, but depending on the make and model, you may get an error like “this device needs too much power.”
The good news is that if you have a phone with a Type-C port, this USB Type-C to USB 3.1 Gen1 Female Adapter Cable should work.
The K3 is bus-powered, so using it with your phone is technically possible, but you’ll be draining your phone’s battery since neither has batteries of their own to draw power from.
Sound
- Playlist: Here!
I’ve utilized both headphone jacks, mainly pairing the Sennheiser HD58X with a balanced 2.5mm cable which sounded great, but I mostly use the K3 single-ended.
Do note that most companies nowadays are gravitating towards 4.4mm as it seems 2.5 is slowly being phased out, much like the transition from micro USB to Type-C (as in the case of the original E10K to K3).
Even companies like FiiO themselves (who’ve relied heavily on 2.5mm in the past) are coming around to 4.4mm.
As mentioned previously, the sound of the K3 is similar to the E10K; i.e. crisp and detailed, but it’s less grainy and smoother overall.
The bass boost on the K3 can also be hit and miss; on some tracks, it sounds great, but not so good on others.
You may be shocked to hear this, but I did an exhaustive A/B comparison between the K3 and K9 pro with the e3.5s and didn’t find much in the way of sound differences between them unbalanced.
Was there a difference in using balanced?
I’d venture to say yes, but it was such a minuscule one that it may have just been in my head.
In other words,
because I knew I was using balanced, my brain compensated by saying “This should sound better, so it is better.”
I will say the K9 Pro balanced into the 3.5s sounded ever so slightly cleaner and more lively, but this simply could have been a minor volume discrepancy error though I did my best to calibrate the levels appropriately.
This also could just be a case of, yes, a balanced connection is going to sound a bit better than an unbalanced one due to factors like reverse polarity and noise eradication.
- Recommended: Balanced vs. Unbalanced Audio Cables
If you’d like to hear some more in-depth sound impressions of the K3, the K3 vs. E10K article I did is rather enlightening and should solidify the main differences between them.
Closing Thoughts
K3 + Koffee
The ultimate question here is of value; is the K3 worth the asking price of just a shade over $100?
This is rather difficult because there are a few things the K3 does that the E10K does not:
The K3 supports DSD, balanced out for headphones, and can run files up to 32-bit/384kHz.
The old E10K does not. That said, the newer E10K TC (Type-C) model does support 32/384, so there’s that.
If you need balanced and DSD, I still think it’s a good value given everything else it can do.
If you don’t need DSD and don’t plan to use balanced headphones, the E10K has more power and can work with harder-to-drive headphones.
I don’t think the K3 is a good investment if you do have high-impedance and/or lower-sensitivity cans that need more juice.
Even with all that said,
I may just end up bypassing both and investing in a K5 Pro since it’s even more versatile than these and has plenty of power for 99% of headphones.
This isn’t a petition for you to spend more money, it comes from a place of experience.
Before giving the E10K away to a Patron in 2021, I had owned the unit since 2018 and really enjoyed my time with it.
I still have the K3 here as it’s super convenient with my 3.5s, but I think the K5 Pro is overall a better investment for most people given that you’d likely just upgrade from the K3 anyway later on down the line.
The K5 Pro can do everything the K3 can do + more.
Interested?
Learn More:
Well, that’s about it for today my friend! I hope you’ve enjoyed this FiiO K3 Review and came away with some valuable insight.
Questions? Comments? Requests? Did I miss the mark on something? Please let me know down below or Contact me!!
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Are you convinced the K3 is a true upgrade from the E10K? What are your thoughts/experience with the K5 Pro? I would love to hear from you. Until next time…
All the best and God bless,
-Stu
6 comments
Hi, is fiio k3 new 2021 better than original fiio k3. It seems that k3 2021 has better dac and higher SNR. What do you think?
Ahmad,
Thank you for stopping by! As long as SINAD is greater than 90dB you’re going to be completely fine. So those slight “upgrades” are kind of null and void imo, and certainly won’t make or break a listening experience.
Let me know if you have additional questions!
-Stu
Thanks for your response. I mostly listen to music casually through my smartphone and I’m really satisfied with the sound quality. When I listen critically, athough the sound coming out of my smartphone is extremely clear, I feel something is missing in my music. After listening critically for a couple of minutes, music becomes boring. You explained in fiio k3 review that this dac/amp has realistic and natural sound. Will it be an upgrade for my smartphone regarding sound quality. My smartphone is Xiaomi Redmi note 8. Thanks a lot.
Ahmad,
My pleasure! What you described is an age old phenomena and unfortunately, it’s not going away lol. I experience exactly the same thing and to be honest with you, it’s simply your brain getting used to the new stimulus. This happens constantly with new gear and it’s just an unfortunate fact of life. It’s also why sometimes I wish I could go back to when I first heard a planar magnetic headphone or something equally as stunning. Because over time you get jaded and cynical about audio products and the companies that shill them constantly.
I have many if you want to hear them, but a quick example I can share with you is the experience of amazing Soundstage through headphones and a DAC like the SoundBlaster X4. The X4 has a pretty amazing setting that makes it feel and sound like you’re listening to speakers. It does an incredible job of tricking you and is one of the most enjoyable things I’ve ever experienced. That said, it fades over the course of a track. For instance, it starts off incredibly realistic and live sounding to the point where I think the sound is coming from my HS7s, and then your brain just gets used to it and the effect isn’t as prominent over time.
So yes, the K3 does have a realistic and natural sound, but whether or not it’s an upgrade from your phone depends on the phone. I would just try the one you have and compare it with a K3. A lot of the newer phones have really excellent built in DACs and you may not notice a difference with a K3 at all. This is just the cold hard truth and reality about digital to analog converters. They are often placed on a pedestal and shouldn’t be. It’s something I’ve been fighting on the blog and channel for many years.
Hope that helps! Keep me posted.
-Stu
Thanks for your meticulous and detailed answer. Fortunately I could find a used fiio k3 in a local audio store. I could exhaustively test k3 with my smartphone. All you mentioned in reviewing different dacs was correct. The difference was small but noticeable and extremely enjoyable. Of course it is felt completely in critical listening. This small difference was like adding a great sort of special flavor or condiment to food. The amount of flavor is little but its effect is too much. I don’t consider myself a seasoned audiophile, but what I experienced was very enjoyable. I could turn up the volume more and more without bothering my ears. The sound was smoother compared with my smartphone. The most enjoyable thing I experienced was when I listened to a piece of native music from my country. I felt the male singer was next to me and he was singing for me. It was a piece of music that I listened many times before. This time it was very real and the strings were more sweet than before. All in all, I fell in love with fiio k3. The more I listen, the more I enjoy it. Now I know what these dacs are made for. They are made for critical listening. Now I have fiio k3 and really enjoy it. Now this is my new question lol. Fiio k3 does not have a battery. What factors might hurt this dac? What factors might make it out of order? If it becomes out of order, is it possible to fix it? I want to have it for ever lol and I might buy a powerful amp in future to add it to the combination. Thanks.
Ahmad,
My pleasure! Thank you for your detailed thoughts about the K3. I’ve had a K3 for many years and it’s held up remarkably well. I don’t think you’ll have to worry about it, but with audio products you never know. The unit is built very solidly and should last a long time. Out of the 77 DACs I’ve used, I haven’t had a single one cease to function. In general the construction of these things is pretty robust/reliable and they pretty much never break down.
And if you need an Amp recommendation to go along with it, let me know! Any other questions just ask.
-Stu