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Fiio A5 Portable Headphone Amp Review

amirm

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#1
This is a review and detailed measurements of the Fiio A5 portable headphone amplifier. It is on kind loan from a member. The A5 costs US $130 from Amazon including free shipping. It came out in late 2016 I think but being just a headphone amplifier, it doesn't obsolete like DACs can.

Due to inclusion of battery and metal case, the A5 is a hefty unit:
Fiio A5 Portable Headphone Amplifier Review.jpg

The volume control is stiff and sticks on the sample unit. Don't know if it was that way when new. It might be pushed in too far but my light attempt at pulling it out did not work.

Most of the controls are on top:
Fiio A5 Portable Headphone Amplifier Controls Review.jpg

There is a Bass boost in the left which I forgot to test. :) The USB jack for charging it is also on the same side and a red LED indicator blinks saying you have plugged it in (curiously it kept doing that well after being charged).

Overall fit and finish is good for a $130 device.

Headphone Amplifier Measurements
As usual we start with our dashboard. For this and the rest of the tests, I disconnected the charging cable. With it connected, it adds fair bit of noise to the measurements:
Fiio A5 Portable Headphone Amplifier Audio Measurements.png


The gain is slightly less than one resulting in the output to be slightly lower than 2 volts that it should be for this test. In actual use that is probably a good thing allowing very sensitive IEMs/headphones to be used at higher volume position.

My NAS where I keep the headphone amp comparison is down right now so I can't pull the graph up to update. But you can mentally plug the SINAD of 115 in there:



As you can see, the A5 would slot well above average. Of course the above devices are AC powered so they don't get to enjoy battery operation than the A5 uses. Still, that is the mode of operation for A5 so it is not entirely unfair.

Frequency response is pretty flat and hence good:
Fiio A5 Portable Headphone Amplifier Frequency Response Audio Measurements.png


Intermodulation distortion versus output power shows a sign of good things to come for A5:
Fiio A5 Portable Headphone Amplifier IMD Audio Measurements copy.png


The low gain mode is very quiet, almost exiting the graph at the bottom!

Using 32 tones as a simulation for "music" we get very low levels of intermodulation distortion yet again:
Fiio A5 Portable Headphone Amplifier Multitone Audio Measurements copy.png


In mid-band frequencies where our hearing is most sensitive, distortion approaches -130 dB which is superb. In other words, there is no audible distortion out of A5 (at this operating level).

Fiio A5 Portable Headphone Amplifier SNR Audio Measurements.png


Once again I don't have a comparison graph but here is the last one I ran for 50 millivolts:



At 90 dB, the A5 would again finish near the top so should be quiet with most sensitive IEMs/headphones.

Most important test is power into different loads relative to noise and distortion (THD+N). Here it is at 300 ohm:

Fiio A5 Portable Headphone Amplifier Power into 300 Ohm Audio Measurements copy.png


Once again, the low gain mode shows its superiority with very quiet performance and almost no rise in distortion. If you hear distortion in low mode, it is in your music or headphone!

Power is quite healthy going past my requirement of 100 milliwatts. The A5 should have little trouble driving high impedance headphones.

There is more distortion with 33 ohm load:
Fiio A5 Portable Headphone Amplifier Power into 33 Ohm Audio Measurements copy.png


Once again low gain is excellent. High gain starts to add distortion and noise so is not competitive with state of the art desktop amplifiers above 10 milliwatts. Mind you, at SINAD of 95 it is still very good until it clips.

Output impedance is comfortably low meaning it won't cause power loss, or change the tonality of your headphone:
Best headphone Amplifier Output Impedance copy.png


Channel matching was surprisingly good:

Fiio A5 Portable Headphone Amplifier Channel Balance Audio Measurements copy.png


You get about 40 dB of attenuation before you lose matching (and output).

Headphone Listening Tests
I started with my 25 ohm Drop Ether CX inefficient closed back headphones. Performance was excellent with plenty of bass, detail and dynamic range. That said, if you go really, really loud the bass starts to distort severely. Dial it back a bit and it will still be quite loud and above normal listening level.

The A5 really shone with the Sennheiser HD-650. The sound was simply superb with no limit in volume. It was so good that I sat there just listening to it rather than my normal setup. The fidelity of the music comes through and makes the HD-650s perform in a way that lower-power/higher-distortion amplifiers cannot replicate.

Thermal Stability
I didn't save the plot because I want to get more mileage on this test. But starting with with USB charger plugged in, showed a lot of random spikes with baseline SINAD of around 95 dB. Unplugged the USB charger cable and performance shot up to 115 dB and was very flat and predictable. So no need to warm up the unit or leaving it on.

I tried to listen while I connected and disconnected the charger. I "thought" I heard a difference but could very well be placebo. I should note that I was using a USB connection to my computer for charging. It may be much more quiet with a dedicated charger.

Conclusions
The Fiio A5 is a delightful surprise when it comes to both objective measurements and subjective performance. When operated on battery, it rivals the best of the desktop headphone amplifiers. There is plenty of power to drive just about any headphone with very low output impedance. I don't think we have seen this combination before. It runs circles around the venerable O2 headphone amplifier for example.

It is my pleasure to strongly recommend the Fiio A5 if you want a battery operated portable headphone amplifier.


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

Christmas season is here and I want to give myself a big present. Problem is, I am too cheap to do that out of my own funds so I appreciate your donation for this very well deserved cause using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Robin L

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#2
I've got [what I guess is] the previous Fiio portable headphone amp, the FiiO E12A Mont Blanc IEM Special Edition Portable. Pretty nice, but my Schiit Magni 3 is a little better.
 

JIW

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#6
The max power in low gain for 300 Ohm looks wrongly indicated. The software (cursor) and added text say 42 mW but the line ends shortly after 10 mW which is closer to the 11.2 mW corresponding to the voltage from the dashboard.

Also, the output impedance chart is quite difficult to read for me since it is so crowded. Could you maybe also mention the output impedance in the text?
 

vkvedam

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#7
Why wasn't the panther impressed :)?
 

mkawa

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#8
one of the units on loan is mine! subjectively, it's the best sounding amp i own, especially with the hd600. maybe the panther is playing soccer because the amp is kicking above its weight? (or a goal; either metaphor seems appropriate :))

quick technical note: it's a very very simple design, probably a jung multiloop topology based on a MUSES02 and LME49600 driven somewhere between +/-7~10v.

the mont blanc e12 that it's derived from used to be called the IEM edition of the e12.

the e12 DIY edition that's still available in a few places had a socketable MUSES02 and LME49600 combo included. unsure of battery voltage on the e12 DIY

also, it seems to be driven completely by USB if it's connected to the charging cable. i can make it ground loop and all kinds of other fun if it's connected to USB. battery life on my 2 year old unit (i preordered it) is now a couple days of moderate listening. if you leave it on, quiescent kills the battery pretty quickly, less than a day.

ps, my unit (which is silver, hence not the one under test) has no issues with volume knob sticking
 
Last edited:

ninetylol

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#9
Interesting. Seems like battery power still has its merits. Makes me wonder if a good linear power supply changes how a amp behaves.
 

raif71

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#10
@amirm - I see a bit of a 60Hz spike, surely if the headphone amp is not connected to anything but the AP, there should be no spike?

Also, have you ever published a 32 tone signal of just the AP loopback, by way of comparison?
You see the 60Hz spike, could be due to charging cable being plugged in? If I understand correctly, amir mentioned this just before the fft graph.

Edit: never mind, Amir answers 2 posts below
 
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NTomokawa

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#11
Showing them how it's done.

I want to see measurements of Ray Samuels stuff and iQube. Those were some of the hype products I remember from my Head-Fi days.
 
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amirm

amirm

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Thread Starter #12
@amirm - I see a bit of a 60Hz spike, surely if the headphone amp is not connected to anything but the AP, there should be no spike?
There are other elements. I had forgotten and had grounded the RCA outs to A5. The signal went through there, and then captured using USB cable (also grounded) to my computer for analysis. So there is mains leakage, albeit, not generated from A5.
 
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amirm

amirm

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Thread Starter #13
Also, have you ever published a 32 tone signal of just the AP loopback, by way of comparison?
I thought I had but my NAS is still down so can't look it up. Can run one later.

Note that when I do that, I invoke the DAC in addition to ADC in the analyzer. For analog devices like the A5, I don't use the DAC in the AP as it has higher distortion than its analog signal generator.
 
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amirm

amirm

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Thread Starter #14
The max power in low gain for 300 Ohm looks wrongly indicated. The software (cursor) and added text say 42 mW but the line ends shortly after 10 mW which is closer to the 11.2 mW corresponding to the voltage from the dashboard.
It is a bug in AP graphing software which I usually catch but missed there. Will fix later when I am in the lab.
 

raif71

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#17
JDS Atom ballpark two years before Atom, impressive Fiio very impresive (touches mpustache and claps in golf claps style)
Sorry, a bit confusing the line "JDS Atom ballpark two years before Atom" Are you trying to say "Fiio A5 ballpark two years before Atom" ?
 

NTomokawa

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Sorry, a bit confusing the line "JDS Atom ballpark two years before Atom" Are you trying to say "Fiio A5 ballpark two years before Atom" ?
I think he meant "the A5 gave JDS Atom-like performance two years before the latter came out".
 
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amirm

amirm

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Thread Starter #20
Have you contacted AP regarding this bug?
This and many others. They just say that the graph is licensed library and they can't do anything about it. And that I should export the data and graph them myself. :(
 
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