FIIO KA15 Portable DAC & Headphone Amp Review

[Egoquaero]

Just my honest opinion. You are mentioning the HD800 and then say that the T71 with its 300 bucks is overkill? It somehow does not compute to me.
Thats a fraction of the cost of the HD800.
I think in your case the T71 is THE way to go. Extra power is never a bad thing especially if you do-if you plan to do heavy processing in the low end which eats up
power headroom pretty fast. It makes no sense to be listening to highly dynamic music as you say, using some of the best headphones and then choose the weaker amplifier.
My two cents. Go for the one with more driving reserves

Yeah you're right.. many things don't compute in this world . I even own a pair of Neumann KH420 with subs, dsp system, whole room treatment with 16 or so gik acoustics bass traps but I'm being miserably stingy with this dsp DAC purchase. It doesn't make sense to me either hahah. Humans are beautiful.
Actually just earlier today I was considering getting the Qudelix T71 but then just before buying it I realized it doesn't even have bluetooth capabilities. I live in Italy and this Qudelix T71 is unreasonably priced on Amazon, at 340 euro. So it might be more sensible to buy the FIIO BR17 at this point, good power, nice design and bluetooth capabilities too. And I can get it at around 200 euro. I might give it a try and see if I can cope with its more primitive EQ interface. Are there other devices that might be worth considering in the category of FIIO BRT17? Thank you all.

 

[Amperage]

Which song or music sample do you mean? Have you tried the soundtrack at the RAA site?

Exactly the same song: Dune Sketchbook Soundtrack - Song Of The Sister, Hans Zimmer . No distortion, clicking, or clipping of any kind - I don't know if it's there on a spectrogram, but there's no difference between both DACs at various levels from very quiet to very loud. It sounds as it should.

 

[jkim]

Exactly the same song: Dune Sketchbook Soundtrack - Song Of The Sister, Hans Zimmer . No distortion, clicking, or clipping of any kind - I don't know if it's there on a spectrogram, but there's no difference between both DACs at various levels from very quiet to very loud. It sounds as it should.

The distortion you want to hear is not clear "clicking" or severe clipping distortion. And the sample already contains quite high background noise. The distortion sounds like occasional crunch in the midst of fluctuating noise levels, which I can hear from a KA15 at hand. In comparison, through an unaffected device, the background noise is not much fluctuating without crunch.

Again, the distortion is not like 10%, or even a few % of the signal. And human ears are easily deceived in this case.

 

[roladyzator]

Awesome review!
I can share few issues I've found as well, which aren't often mentioned:

EQ:
- The high and low shelf filters are described with Q, but it seems to actually be the Slope parameter.
- This means to get the Q=0.71, as in Oratory1990's PDFs, one needs to set Q to 1.

Balanced output can have loud pops with active speakers
- The balanced output works generally works with a 4.4mm to 2x XLR adapter (tested with Kali IN-8 V2), but there are issues.
- After stopping playback, after few seconds there is a very loud pop. It is not affected by volume setting. I think it goes from 0 to full output voltage an back in an instant. My Kalis are ~1m away from me and it was a bit scary.
- One can disable sleep mode (hold volume down before connecting to USB) to disable this effect.
- On 1.0.4 firmware, the sleep mode is entered after 3 minutes instead of few seconds of silence.
- Without sleep mode, stopping the playback still shuts down some circuitry (current indicator falls from 140 mA during playback to 100 mA instead of 30 mA in sleep mode). A noise is emitted to the speakers, as if the ground-loop-breakage feature of the balanced output wasn't working.
- One can fool the device to play something really quiet using Sound Keeper (or an online tone generator with minimum volume, reduced volume in Windows volume mixer with Ears extension with -25 dB gain). From my experiments, 10 Hz Sine or pink noise in the -100 dB area is enough to keep the KA15 alive so it doesn't produce any noise.
Yes, you have to add noise to prevent noise

There are no pop or noise issue with balanced out when connected to headphones.

Silence after starting playback:
- It takes half a second or so before playback starts after pausing. This was much worse on my Fosi DS2, but my Samsung Dongle doesn't have that issue. If you keep KA15 alive, there's no silence, of course.

Anyway, I like mine and while I'm surprised by the poor measurements for low-to-mid signal levels, it still sounds good with my headphones and speakers and does a lot of useful things. But, it's not an easy recommendation anymore.

 

[Amperage]

The distortion you want to hear is not clear "clicking" or severe clipping distortion. And the sample already contains quite high background noise. The distortion sounds like occasional crunch in the midst of fluctuating noise levels, which I can hear from a KA15 at hand. In comparison, through an unaffected device, the background noise is not much fluctuating without crunch.

Again, the distortion is not like 10%, or even a few % of the signal. And human ears are easily deceived in this case.

Ok, I went down the rabbit hole. This is very interesting.

I've tried to reproduce the sound on the recorded samples at RAA's site - where I can hear that occasional "crunch" and think I understand what's identified. I've been trying to reproduce them by switching through all 6 filters, 2 power modes, and 2 outputs (IEMs and headphones, balanced & SE).

My KA15 was on firmware version 1.0.3, and is on 1.0.4 since the last hour or so. I've also always switched between NON-OS and FAST-PC filters, and hadn't heard anything as manifest as the recorded samples on the site.

Because I think I know what I'm looking for now, I (again) think that maybe I've managed to hear a much lower level/volume of "crunch" and depending on filter choice? These effects don't appear to happen on NON-OS, but may (?) occur on the 4 remaining Fast and Slow filters. Out of curiosity, what firmware and filters did you use for testing? If it's still available to you, can you cycle through filters to see if you can spot any changes?

EDIT: I'm going to add that like @roladyzator , I also like mine quite a lot - it drives everything I need it to, looks nice, and takes up next to no space. Again, thanks for the review and extra info on these CS431** DACs. I'll keep an eye out on how it evolves.

 

[jkim]

Ok, I went down the rabbit hole. This is very interesting.

I've tried to reproduce the sound on the recorded samples at RAA's site - where I can hear that occasional "crunch" and think I understand what's identified. I've been trying to reproduce them by switching through all 6 filters, 2 power modes, and 2 outputs (IEMs and headphones, balanced & SE).

My KA15 was on firmware version 1.0.3, and is on 1.0.4 since the last hour or so. I've also always switched between NON-OS and FAST-PC filters, and hadn't heard anything as manifest as the recorded samples on the site.

Because I think I know what I'm looking for now, I (again) think that maybe I've managed to hear a much lower level/volume of "crunch" and depending on filter choice? These effects don't appear to happen on NON-OS, but may (?) occur on the 4 remaining Fast and Slow filters. Out of curiosity, what firmware and filters did you use for testing? If it's still available to you, can you cycle through filters to see if you can spot any changes?

EDIT: I'm going to add that like @roladyzator , I also like mine quite a lot - it drives everything I need it to, looks nice, and takes up next to no space. Again, thanks for the review and extra info on these CS431** DACs. I'll keep an eye out on how it evolves.

Note that we are talking about 0.06% distortion in the worst case. That is one big reason why the issue of subjective audibility is difficult to resolve. Also, there should be infinite possibilities of this distortion occurring in audio content. That is another big reason why this issue should not be considered based on subjective listening of ONE sample of an audio clip, and why systematic measurements (even a simple sweep of test tones over varied signal levels) are important.

I believe the tested KA15 is with the firmware version 1.0.3, but I doubt the new firmware has addressed the issue. And the behavior does not depend on a particular sample rate or digital filter. It always occurs regardless. By the way, I would not use an NOS filter as I am an objectivist believing in measurements..