FiiO M15S Digital Audio Player Hands-on Review: Flagship Portable Sound

For those who are paying attention, Chi-Fi is applying a consistent competitive edge in the audiophile industry. FiiO, being one of the leading players in this wave, has been taking advantage of this development by expanding its portfolio at an astonishing rate. In the last few months, the Guangzhou-based audio tech company has released its first desktop DAP - the R7, its first monitor-powered speakers - the SP3, and its first over-ear headphones - the FT3.

Thankfully, amidst the exciting new expansion, FiiO didn't forget its origins and reintroduced its previous flagship DAP, the M15, as the M15S. However, there have been significant changes in the positioning of the M15S. It is no longer the flagship DAP, as that position has been taken over by the M17. Additionally, the M15S no longer features the usual dual-DAC chip found in FiiO's premium DAPs, unlike the original M15 which boasted the highly sought-after dual AK4499EQ setup. Now, the question arises: How will the new M15S perform in real-life, and how does it compare now that it appears to be in the shadows of the M17? Let's dive in to find out.

Upgraded Premium Build

The build of the FiiO M15S bears many similarities to the M15 DAP. It retains the popular all-metal hip flask design with curved sides, a large display, and a glass back. However, there are some notable changes in the M15S. The controls have been distributed to both sides of the device instead of being solely on the left side, which improves accessibility and makes it easier to navigate by touch alone. Furthermore, the buttons now have a convex profile, enhancing the ease of pressing them.

FiiO has also added volume up/down buttons to the M15S, serving as a secondary volume control and acting as a backup option. However, it's worth mentioning that I don't anticipate the volume knob breaking any time soon, as it is one of the highest-quality volume knobs I have come across in my audio product reviews. It even surpasses the volume knobs found on flagship devices from A&K that cost three times as much. The sensitivity of the volume knob is perfectly matched with a silky smooth but heavy resistance, allowing for precise adjustments in volume. The fact that the button is exclusively dedicated to volume control, without any other functions or depressions, adds a touch of luxury and contributes significantly to the premium feel of the M15S.

At the bottom of the device, you'll find the Micro-SD card tray along with the USB-C port, which supports charging with QC 4.0 and PD 3.0 chargers. The M15S is equipped with a substantial 6200 mAh Li-ion battery, allowing for extended playback sessions while on the go, with a battery life of up to 10 hours.

Although the M15S may no longer hold the flagship title among FiiO's DAPs, it still retains its status as the flagship portable DAP in my opinion. Weighing in at 345g, the emphasis here is on its portability. With a weight that is approximately half that of the M17, the M15S is indeed better suited to be referred to as a "portable" device.

Single DAC versus Double DAC

Indeed, the M15S shares an important commonality with the M17, and that is the presence of the ES9038PRO DAC chip. However, the difference lies in the fact that the M15S utilizes a single DAC chip, whereas the flagship M17 employs a dual-chip setup. While the ES9038PRO is a high-quality DAC chip typically found in professional audio workstations and premium home theater equipment, featuring 8 channels, the question arises whether having multiple DAC chips would be advantageous or not in real-life applications.

In reality, the results were surprising. When comparing the M15S, equipped with a single ES9038PRO DAC chip, to the M11 Plus, which features a dual DAC chip setup, there was an undeniable improvement in terms of clarity and dynamic performance. Whether this improvement is due to the superior hardware of the M15S or because FiiO's design team has honed their ability to tune and apply the ES9038PRO after utilizing it in the M17 DAP, Q7 DAC/Amp, and K9 Pro Desktop DAC/Amp, is uncertain. However, what was clear is that the M15S delivered better sound quality than the M11 Plus.

Desktop Mode: Hidden Super Power

In addition to its surprising DAC chip implementation, the M15S also features another unexpected feature that was carried over from the M17: the Desktop Mode. Similar to the M17, which unlocks a hidden desktop mode when connected to external DC power, the M15S activates the 'Ultra High' gain mode when it receives external power through its USB-C port. This feature is particularly noteworthy as I discovered it to be one of the most significant aspects of the M15S.

Although the M15S doesn't reach the impressive 3000 mW power output of the M17, the 1200 mW output from both the left and right channels is what truly distinguishes the M15S from the M11 series. While its capacity to drive headphones to their maximum potential may be limited, when paired with a capable IEM like the L'Acoustic Contour XO (made by JH Audio), the additional power boost in the Ultra High gain mode brings out nuances and details in the IEM that other DAPs simply cannot achieve. It enhances the overall color and presentation of the IEM, providing a unique listening experience.

Harnessing the additional power boost and leveraging the capabilities of the ES9038PRO chip, I was able to experience a jaw-dropping soundstage and remarkable instrument separation even with entry-level earphones like the Sennheiser IE 200. The M15S proves to be an excellent choice when it comes to driving capable earphones that require a clean and powerful music source. From my perspective, it stands out as one of the top options currently available on the market.

Seamlessly Blending Accessories

I understand that I may sound repetitive in my FiiO reviews, but I cannot help but reiterate that FiiO consistently exceeds expectations when it comes to accessories, and the M15S is certainly no different. The inclusion of the popular cognac leather case, complete with a small magnetic flap to safeguard the top of the volume knob, mirrors the excellent design of its predecessor. Additionally, FiiO once again incorporates a metal grill on the back of the device to enhance heat dissipation. FiiO's commitment to providing top-notch accessories greatly enhances the overall user experience and reaffirms their reputation for delivering exceptional products.

An noteworthy addition to the package is the DK3S heat dissipation dock, which features a USB-powered fan. This dock not only provides a dedicated place for the M15S on your desktop but also serves as an effective cooling solution. FiiO's inclusion of two USB cables, one for the fan and another for data/recharging purposes, further showcases their commitment to convenience and functionality. Moreover, the provision of a USB-C to USB-A adapter ensures compatibility with various power adapters, leaving no stone unturned in terms of accessories. FiiO's meticulous attention to detail in providing comprehensive accessories highlights their dedication to customer satisfaction and enhances the overall user experience.

Final Verdict

I'm sure FiiO will be pleased with me disagreeing with their market positioning of the M15S. While the company refers to it as a sub-flagship portable music player, I'm making the case that it is, in fact, the flagship DAP. This is due to its significantly higher level of portability compared to the M17. Furthermore, its flagship status is reinforced by the inclusion of a desktop-grade DAC chip and an exceptionally precise and refined physical volume knob.

After thoroughly evaluating the FiiO M15S, we have reached the conclusion that it stands as the flagship portable sound source for IEMs and earphones, despite the M17 being the most capable DAP for driving full-sized headphones. In other words, for those seeking the ultimate audiophile listening experience while on the go, we confidently recommend the M15S over the M17. As a result, we are proud to award the FiiO M15S with the IBTimes Recommended Badge.