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Review and Measurements of Fiio K5 Pro

amirm

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#1
This is a review and detailed measurements of the Fiio K5 Pro DAC and headphone amplifier. It was kindly sent to me by the company. The K5 Pro is a budget product, costing US $150 on Amazon with free shipping.

The Fiio K5 looks decent and sports a nice, large volume knob which I appreciated:

Fiio K5 Pro DAC and Headphone Audio Review.jpg

As you can see, there is the usual input selector and triple gain setting. An informative LED light around the volume control changes color depending on whether the device is in use.

The back panel is as you expect:

Fiio K5 Pro DAC and Headphone Back Panel Audio Review.jpg

The power supply is rather unique, outputting 15 volts which typically indicates good power delivery when it comes to headphone output. Note that on AC side of it, the removable cable has the three-pin, round holes like laptop power supplies do.

The rear Line Out changes with volume on the front but not the gain switch. The headphone output and rear Line Out are active at the same time so you have to remember to disconnect one or the other if that is what you intent.

DAC Audio Measurements
As usual, we start with our dashboard, measuring what comes out of the line out:
Fiio K5 Pro DAC and Headphone Audio Measurements.png


Well, this is disappointing. I almost put aside the unit thinking it is not worth testing more. The SINAD puts it in the fourth quadrant of all DACs tested:
Best Audio DAC Reviewed and Measured.png


Oops, forgot to mark which one it is in that graph. Sorry about that. :) Click on it and you should be able to find it.

Note that SINAD improves good bit to 90s when the output is lowered to 1 volt or so.

Before giving up, I ran a power test on its headphone out and found that quite good. So I continued with testing that port, rather than line out.

Headphone Amplifier Audio Measurements
Here is our jitter test:

Fiio K5 Pro DAC and Headphone Jitter Audio Measurements.png


That's quite good as indicated on the graph. Worst case jitter components are at -135 dB which is way, way lower than threshold of hearing.

Linearity really impressed me:
Fiio K5 Pro DAC and Headphone Linearity Audio Measurements.png


Intermodulation+noise test shows some weakness but nothing badly broken:
Fiio K5 Pro DAC and Headphone IMD Audio Measurements.png


Here is our dynamic range:

Fiio K5 Pro DAC and Headphone SNR Audio Measurements.png


Good enough on 2 volt dynamic range but middle of the road on 50 millivolts of output:

Lowest Noise Headphone Amplifier.png


Most important test is power versus noise and distortion:
Fiio K5 Pro DAC and Headphone Amplifier Power into 300 Ohm Audio Measurements.png


We see that the Fiio K5 Pro has a lot of power, running neck and neck with Topping DX3 Pro. Yes, distortion rises at the limit but there is no clipping.

Here it is at 33 ohm:
Fiio K5 Pro DAC and Headphone Amplifier Power into 33 Ohm Audio Measurements.png


We have nearly 1 watt of power into 33 ohm load!

Output impedance is comfortably low:

Best Headphone Amplifier Output Impedance Measurements.png


And channel balance as expected is perfect due to digital attenuation in the DAC:
Fiio K5 Pro DAC and Headphone Channel Balance Audio Measurements.png


Headphone Listening Tests
I started testing with my new DROP + MRSPEAKERS ETHER CX headphones which have a very low, 25 ohm impedance. The Fiio K5 Pro was comfortable to drive them hard and very well. Maybe at the last 5 to 10% of the volume it got a bit distorted but in any reasonable listening scenario, it was very comfortable and satisfying.

The experience with Sennheiser HD650 improved yet again. There was enough power to even vibrate my earlobes! :D Excellent dynamics were there as a result with great bass and overall joy.

Conclusions
The typical approach in a product like this is to build a DAC that performs very well. And then throw in a headphone amplifier that is just adequately. Here, the DAC is just good enough to drive the amp. The amp is designed to produce a lot of power and at low enough distortion to not be an audible issue. For a budget product and its intended use which is with headphones, it is a fine compromise.

In that regard, and in the context of a budget product that is designed reasonably well, I am going to recommend the Fiio K5 Pro.

------------
As always, questions, comments, recommendations, etc. are welcome.

As you can tell I am working overtime in the night shift to produce the second review of the day. There is just so much gear to review. You don't have to pay me overtime but the panthers are saying the law requires them to be paid time and a half. So please donate using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

deafenears

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#2
The typical approach in a product like this is to build a DAC that performs very well. And then throw in a headphone amplifier that is just adequately. Here, the DAC is just good enough to drive the amp. The amp is designed to produce a lot of power and at low enough distortion to not be an audible issue. For a budget product and its intended use which is with headphones, it is a fine compromise.
So, is this a K5 headphone amplifier which you measured earlier in the year with the DAC thrown in?
 
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#5
Disappointed,Still can't pose a threat to the king of budget DAC D10。

The good news is that it has analog input,Analog input is very good。
 
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#7
Disappointed,Still can't pose a threat to the king of budget DAC D10。

The good news is that it has analog input,Analog input is very good。
Actually it's not an accurate comparison. Two different units. Topping is only dac. With only usb in. Fiio is dac with 4 inputs (3 digital, one being analog) and what's more important with line in. So could be used in many other ways.
Topping is better dac - yes. But Fiio is more versatile unit, just different target.
So these two shouldn't be compared.
 

bunkbail

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#9
Actually it's not an accurate comparison. Two different units. Topping is only dac. With only usb in. Fiio is dac with 4 inputs (3 digital, one being analog) and what's more important with line in. So could be used in many other ways.
Topping is better dac - yes. But Fiio is more versatile unit, just different target.
So these two shouldn't be compared.
I think he's referring to Loxjie D10.
 

flipflop

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#10
Thank you for the thorough review despite the underwhelming FFT.
I know you usually don't post the FR unless there's something wrong with it, but if you could make an exception, or just assure me that it's flat from 20 kHz and down, it would be much appreciated.
 

daftcombo

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#11
I'm very surprised this unit can sound so good on Mr. Speakers with such a poor SINAD.

@amirm
Can we have THD+N VS Power for the DAC?
THD+N VS Frequency?
 

amirm

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#15
@amirm It might be interesting to check also Line In -> Phone Out
It is the same as digital in since the DAC is not the limiting factor:

Fiio K5 Pro DAC and Headphone Analog In Audio Measurements.png


I did not try to mess with it and reduce the impact of the mains leakage so ignore that part.
 

mkawa

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#17
the tradeoff is probably better performance at super high impedance. i mean, he got 1W out of it without clipping, yikes! sounds like a great budget amp for a pair of akg k1000
 

Vovgan

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#18
It is the same as digital in since the DAC is not the limiting factor
Sorry, but if this is the result for “line in -> (head?)phone out” and in the main post you provided the same measurements for DAC ( “digital in -> line out”), are these not independent measurements for DAC/headphone amp sub-systems, rather than one limiting the other? Shouldn’t the total performance of this device (“digital in -> headphone out”) be a sort of multiple of these two measurements? Shouldn’t distortions and noise of DAC and headphone amp compound? Or am I misinterpreting what was measured?
 
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amirm

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#19
Wait so it's worse than the original Fiio K5's 107dB SINAD there?! :oops:
It seems to be. Strange as I would have thought they are using the same circuit. When I have time I will try to confirm.
 

amirm

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#20
Sorry, but if this is the result for “line in -> (head?)phone out” and in the main post you provided the same measurements for DAC ( “digital in -> line out”), are these not independent measurements for DAC/headphone amp sub-systems, rather than one limiting the other? Shouldn’t the total performance of this device (“digital in -> headphone out”) be a sort of multiple of these two measurements? Don’t distortions of DAC and headphone amp compound? Or am I misinterpreting what was measured?
The one in the review was from the Line Out with USB input. This is with Analog in, Headphone out as requested.

But no, you don't multiply the subsystem performance. It is in dB scale so it doesn't work that way. For example, if you have two subsystems cascaded with each having a SINAD of 80, the resulting SINAD will be 74 dB. If one is 90 dB, it almost makes no impact on the total SINAD as the 80 dB one dominates. Use this calculator to play with: http://www.sengpielaudio.com/calculator-coherentsources.htm
 
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