FiiO PL50

The review sample was kindly provided free of charge in exchange for an honest review.
I didn't receive monetary or any other kind of compensation and I don't use affiliate links.
The price of the FiiO PL50 is $150 and you can buy it from here.

Why do I need a good quality power supply?

There are a lot of audio devices that are powered by an external power adapter which is usually a generic switching power supply (SMPS) of average quality at best.
And while the device itself should have an internal rectifying and regulation circuit, it is always better to start with an already clean and noise free mains supply that can be more accurately and effectively filtered out by the internal filtering stage.

An external audio power adapter can be either an SMPS or a linear power supply (LPS) both of them having some advantages and disadvantages and are suitable for audio use as long as they are of the highest quality and specifically designed for audio applications.
This review is not about an LPS versus an SMPS comparison and which one is better for audio use but it is rather about the benefits of using a high quality external power supply, (an LPS in the case of the FiiO PL50) against the bad quality SMPS that usually comes bundled with most audio devices.

A well designed LPS has a stable voltage output with smaller ripple and lower noise.
Furthermore this already lower noise is fixed in a frequency where human ears are relatively insensitive whereas in a switching power supply this noise is of higher frequency and can easily interfere with the analog portion of the audio circuits due to radiation greatly impacting sound quality.
This noise can even indirectly affect the digital portion of the audio circuit further decreasing sound quality.
Since the noise of an LPS is already fixed in a lower frequency it can be more effectively filtered by the audio device itself.



A linear power supply responds more quickly to load fluctuations, it is not as susceptible to EMI and RFI and has better isolation from the mains noise while it also has lower output impedance.
In contrast a bad quality SMPS is very susceptible to both EMI and RFI so it requires good shielding, something that a generic SMPS doesn't have.

Additionally a low quality SMPS produces a self generated high frequency noise that also backwashes into AC mains and pollutes the rest of the audio chain.
It also has greater ripple voltage and slower transient response.



The FiiO PL50

The FiiO PL50 is a high quality, low noise, regulated Linear Power Supply which supports both 12V and 15V outputs (with a maximum 3A current for the first and 2A for the latter) that is specifically designed to successfully address all the above mentioned issues.
Additionally the PL50 is also equipped with a filter circuit in the AC end for filtering out interference generated from other audio devices being used on the same AC outlet.



Inside the PL50 there is a custom 50VA audiophile-grade toroidal transformer made of high quality Nippon steel iron core and high purity, oxygen free, copper wires for high efficiency, higher precision, more stable voltage and higher energy output.
High quality components were chosen for every part of the circuit such as Shindengen bridge rectifiers, TI voltage regulators and Nippon Chemi-Con and Rubycon capacitors.
The PL50 features an advanced circuit design that has been optimized to ensure reliable operation, EMI filtering, transformer rectification, voltage regulation and multi-stage filtering.
The PL50 has various safety certifications and has been approved for use inside the EU.



Design and interface

The PL50 is a simple, rectangularly shaped device with a small digital display at the front showing the output voltage.
A switch at the back is used to select between 12V or 15V DC while the DC output is provided through a high quality, aviation grade, GX16-2 socket.
The PL50 has a minimalistic industrial design with a chassis made from aluminum - magnesium alloy that effectively shields the internals from external noise and interference.
Build quality and finish are excellent.
The PL50 comes with a mains cable and a high quality DC output cable with a 5.5x2.1mm barrel plug which is readily compatible with the FiiO K5 PRO/(ESS), K7, M17, Q7, R7 and many devices from other brands.



Listening impressions

I have been using and testing the PL50 for more than a couple of months with the K5 PRO ESS, K7, Q7 and M17 from FiiO and the Aune Flamingo Tube DAC.
Most of the listening was done with the Focal Clear Mg, HiFiMan Arya Stealth and Sennheiser HD660S with pure silver cables made by Lavricables.

Adding a high quality external linear power supply to the chain doesn't induce some kind of magic, it is science, using clean and noise free mains results in a clearer sound with less distortion and audible noise.
It is something like using fresh spring water instead of tap water to make a cup of coffee.
Every coffee aficionado will immediately notice the difference in taste.
Although this is a purely subjective review without scientific justification, it is not that difficult to search the web and discover at least a couple of measurements where they measure the noise and how a power supply behaves under real audio loads and compare the results to a generic SMPS.



Please remember that the PL50 will not in any way transform your audio device into something different sounding than it is and you should not expect any frequency response or some other kind of sound signature alterations, a linear power supply will not do this kind of job.
You should also keep in the back of your mind that we are talking about minor improvements and not jaw dropping, night and day differences while the better the rest of the chain is, the more noticeable are the sonic improvements.

Adding the PL50 to your audio chain is really the icing on the cake.
The first thing to notice is the absolutely black and noise free background, the enhanced sense of tranquility that helps a lot with detail retrieval, you can more easily spot the finest nuances especially when listening to overloaded music passages.
Then there is an improvement in overall clarity and transparency, something that gets easily observed when going back and forth between the PL50 and the wall wart adapter.
You can also hear more precise layering, ambience information comes out more effortlessly and the soundstage gains in width and space like when listening to the following recording.



With the same musical example which calls for sudden and well contrasted dynamic swings the PL50 improves transients speed and adds more impact to the sound with faster attack.
One last area of improvement is in the timbre texture which becomes more natural and smoother sounding especially in the higher frequencies.

Not only for your DAC

Another area of application for any 12V audio grade power supply is for powering your Ethernet router.
Most audiophiles that have experimented with upgrading the power supply of their router to something better with lower noise will already know how beneficial is to the audio quality of the digital signals.
It's been a couple of years now that I have ditched the generic wall wart for an iFi iPower 12V power adapter and never looked back since then.
Using the PL50 for the same application provided an even calmer background while listening to music from high resolution streaming services sounded a touch less digital and glary.



In the end

All the above described incremental sonic improvements are, in my opinion, well worth it to justify adding an external audio-grade power adapter wherever is needed and of course don't exclusively apply to the FiiO PL50.
What is really interesting about the FiiO PL50 though and sets it apart from the competition is the very low asking price for such a proficiently designed and well made LPS with dual output rails (12V and 15V) and a 3A of maximum current.
When considering that there are some other similarly specced power supplies from well established "audiophile" brands that cost well above 1K-USD then the FiiO PL50 is literally an absolute bargain that brings subtle but audible improvements to your audio chain for an asking price less than that a medium-grade audio cable.

Test playlist

Copyright - Petros Laskis 2023.