This is a review and detailed measurements of the Fiio M15 DAP. It is on kind loan from a member and costs US $1,300 including Prime shipping on Amazon.
The M15 runs Android but also has a dedicated, player mode (which I did not test). It feels substantial like most DAPs:
When I powered this unit up, I was pleasantly surprised by owner's installation of Roon. Fired that up and found it quite nice to have for around the home given the fact that I am a Roon user. Alas, while there was some kind of upgrade going on, Roon constantly stopped and could not fetch my music. So performance -- Wifi or CPU -- is not that great or at least anything getting close to a modern mobile phone.
I don't know which version of Android it is running. I had a hard time navigating it as I could not figure out the back button, etc. Not a huge deal but was not as close to my regular phone as I wished. This is as much Android's fault as is Fiio's.
Nice suite of jacks are provided for both unbalanced and balanced:
And of course one of the main benefits of these players is the hardware "VCR" controls:
Fiio M15 Measurements
For testing, I used a USB jack and put the unit in USB DAC mode. This allowed me to run my full suite of DAC and headphone amp tests. So let's start with the former, using the unbalanced headphone out:
This puts the performance is very good category:
Balanced performance was a bit worse:
Intermodulation versus level showed an "IMD hump" which is strange as this is an AKM DAC chip not ESS:
Note how in this case balanced performance is much better as far as noise level. Not sure why it is reverse of dashboard.
Dynamic range at 4 volts is excellent:
Performance at 50 mv output for sensitive IEMs is above average:
Jitter performance is very good other than broadening of our main tone that indicates low frequency random jitter:
The impairment is totally inaudible though due to its nature and exceptionally low level. The performance here is much better than any USB dongle.
Multitone distortion shows rising noise in low frequencies:
We see the same thing in THD+N vs frequency:
Linearity test is nailed indicating very good accuracy:
A number of filters are provided:
Most important test here is power availability so let's test that using 300 ohm load first:
Balanced output is quite good for a portable device at 64 milliwatts. Unbalanced is a quarter of that which while not terrible, is not that much power at 16 milliwatts.
Strangely again, unlike the dashboard, the balanced output is superior as far as noise level. And even with the "IMD hump" performance is desktop class in both noise and distortion.
Power naturally increases a lot when testing into 32 ohm load:
Varying the impedance from 600 to 12 ohm we see small load dependency:
Fiio M15 Listening Tests
Using balanced connection to my Drop Ether CX, there was plenty of power, dynamics and detail. Given the difficulty many portable products have in driving this headphone, this is a very good result.
Using unbalanced connection, I had just enough power for Sennheiser HD650.
Conclusions
The Fiio M15 targets desktop class performance and it almost gets there. In absolute there, i.e. SINAD and Dynamic Range, it is there already. But there is a mid-level distortion that is unfortunate.
Overall, the Fiio M15 manages to best just about any dongle or phone you would use instead of it and handily so. So I am going to put it on my Recommended list.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The M15 runs Android but also has a dedicated, player mode (which I did not test). It feels substantial like most DAPs:
When I powered this unit up, I was pleasantly surprised by owner's installation of Roon. Fired that up and found it quite nice to have for around the home given the fact that I am a Roon user. Alas, while there was some kind of upgrade going on, Roon constantly stopped and could not fetch my music. So performance -- Wifi or CPU -- is not that great or at least anything getting close to a modern mobile phone.
I don't know which version of Android it is running. I had a hard time navigating it as I could not figure out the back button, etc. Not a huge deal but was not as close to my regular phone as I wished. This is as much Android's fault as is Fiio's.
Nice suite of jacks are provided for both unbalanced and balanced:
And of course one of the main benefits of these players is the hardware "VCR" controls:
Fiio M15 Measurements
For testing, I used a USB jack and put the unit in USB DAC mode. This allowed me to run my full suite of DAC and headphone amp tests. So let's start with the former, using the unbalanced headphone out:
This puts the performance is very good category:
Balanced performance was a bit worse:
Intermodulation versus level showed an "IMD hump" which is strange as this is an AKM DAC chip not ESS:
Note how in this case balanced performance is much better as far as noise level. Not sure why it is reverse of dashboard.
Dynamic range at 4 volts is excellent:
Performance at 50 mv output for sensitive IEMs is above average:
Jitter performance is very good other than broadening of our main tone that indicates low frequency random jitter:
The impairment is totally inaudible though due to its nature and exceptionally low level. The performance here is much better than any USB dongle.
Multitone distortion shows rising noise in low frequencies:
We see the same thing in THD+N vs frequency:
Linearity test is nailed indicating very good accuracy:
A number of filters are provided:
Most important test here is power availability so let's test that using 300 ohm load first:
Balanced output is quite good for a portable device at 64 milliwatts. Unbalanced is a quarter of that which while not terrible, is not that much power at 16 milliwatts.
Strangely again, unlike the dashboard, the balanced output is superior as far as noise level. And even with the "IMD hump" performance is desktop class in both noise and distortion.
Power naturally increases a lot when testing into 32 ohm load:
Varying the impedance from 600 to 12 ohm we see small load dependency:
Fiio M15 Listening Tests
Using balanced connection to my Drop Ether CX, there was plenty of power, dynamics and detail. Given the difficulty many portable products have in driving this headphone, this is a very good result.
Using unbalanced connection, I had just enough power for Sennheiser HD650.
Conclusions
The Fiio M15 targets desktop class performance and it almost gets there. In absolute there, i.e. SINAD and Dynamic Range, it is there already. But there is a mid-level distortion that is unfortunate.
Overall, the Fiio M15 manages to best just about any dongle or phone you would use instead of it and handily so. So I am going to put it on my Recommended list.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
