Sound Analysis.

The sound analysis of the S3 was conducted using various IEMs and headphones, while playing a variety of test tracks, including Agnes Obel’s “The Curse”, Sandro Cavazza’s “So much Better” (Avicii remix), C-Bool’s “Never Go away”, Ed Sheeran’s “Shape of You”, Alan Walker’s “Darkside”, Galantis’s “Hunter”, Iggy Azalea’s “Black Widow”, Indila’s “Boite en argent”, Dua Lipa’s “Love Again”, Counting Crows’ “Big Yellow Taxi”, Bob Marley’s “Jamming”, David Elias’s “Vision of Her”, Michael Jackson’s “Dirty Diana”, and SaberZ’s “Without Your Love”. The device arrived with many hours of burn-in under its hood, so I began my analysis right away.

I prefer to describe the DAP/DAC/source sound by comparing it to other DAPs/DACs/sources and pairing it with different IEMs/headphones, since it doesn’t have a distinct sound on its own. We perceive the sound through connected IEMs/headphones or by comparing differences relative to the source using the same pair of IEMs/headphones. This is my subjective opinion, based on my analysis of the S3’s sound, using it connected wired and wireless with my Galaxy S25 phone.

While analyzing the S3, I hear a huge, 3D holographic soundstage expansion; very technical, reference-quality sound performance without being analytical, bright, or revealing. I find the background super black, with fast note-on/off transients and details popping out of the blackness. I hear a very neutral signature with a natural, transparent tonality. The layering and separation of sounds are effortless and precise, with a layer of controlled air between the sounds, vocals, and musical instruments. If I were to describe the S3 in one word, I would call it “effortless,” since it has one of the most effortless, uncolored, very resolving, and still natural sounds I have heard from many dongles and even DAPs. The S3 is a great source for analyzing the performance of connected gear, such as IEMs or cables, or the actual sound (when using reference-quality earphones/headphones), because it delivers the music without any coloring or tonal exaggeration. It still enhances the sound performance, from a technical perspective, such as giving your DD drivers better extension, tighter punch, and more control in note decay, or keeping your lower mids close to neutral performance without any added body to color the sound, as well as keeping treble extended, airy, without any boost or roll-off. And this enhancement feels more on a technical level, rather than coloring the sound or boosting/cutting any frequencies, keeping it natural and true to the original recording without any exaggeration.

When switching between 3.5mm and 4.4mm, I hear identical sound performance in terms of tuning and technical aspects, with the only difference being that I need to boost the volume by about 3-4 clicks when switching to the lower-power 3.5mm output.

Wired (USB-C OTG) vs Wireless (WT-2 LTTP dongle) – This was probably my most anticipated test.  Both yielded 48k/24b readings on the S3 display. When it comes to tuning, it is almost identical, delivering the same neutral sound sig with a natural, transparent tonality. I still hear the same bass impact, the same natural, detailed mids, and extended, airy treble. But there are a few minor differences. I don’t even know if everybody will be able to spot this unless you have trained ears and are using more reference-quality, neutral, uncolored monitors. When used wired, I felt the soundstage width stretched a tiny bit wider. I mean, this is at a splitting-hairs level of difference, but I do hear it. Another change, which I find a bit more noticeable, is that in wireless LTTP mode, I hear notes gain a bit more weight and density, while on a wired connection, they are a bit lighter and airier. Again, some might not even hear it if you are using more colored or heavier-bass-impact monitors. But I was able to spot this minor difference with Jewel IEMs.

Switching between Super High gain and High gain didn’t yield much change in sound quality when using IEMs, just a 4-5-click drop in volume. For more demanding headphones, like R70x, used with S3 (60/100 volume) vs GT2 (52/100 volume), Super High gain drove them to their full potential, with them sounding very clean, neutral, and tight, without any bloat or coloring, and with a more open, expansive soundstage. Relative to GT2, there was not much of a sound difference, just, as mentioned before, slightly more note weight with GT2, while having more transparency with the S3 wired connection, and similar note weight and slightly more body as GT2 while using the S3 in wireless LTTP mode.

With Sensitive IEMs, such as VE10, I hear a deep black background with zero hiss of any kind, even in Super High gain setting.  That was impressive.

Source pair-up.

While testing S3 wirelessly with WT-2 connected to my Galaxy S25 versus to good-old LPGT, I saw “PCM 48kHz, 24bits” on S3 w/S25 and “PCM 44.1kHz, 32bits” on S3 w/LPGT. The sound performance was very close, with S25 as the wireless source yielding slightly less colored mids and a bit airier treble, while LPGT as the wireless source was a little warmer and smoother. The difference wasn’t night and day, and you can argue it’s all digital/wireless, with LTTP compensating for the differences. Nevertheless, I did hear a few subtle changes, as mentioned above. For me, it makes more sense to use S3 with WT-2 connected to my smartphone than to use a DAP. After all, the point and advantage of wireless connection is to leave an extra DAP brick at home and use a small S3 with a compact WT-2 adapter and the smartphone on the go.

Comparisons.

I used Aroma Jewel in my comparisons, matching volume while listening to the same test tracks. Additionally, I’m primarily focusing on the differences in sound as I perceive them. These are my quick analysis notes, including the comparison to Lotoo’s flagship GT2 and previous-generation S2 dac/amp, along with some other popular DAC/amp dongles.

S3 vs GT2 – it’s not the first time I’ve seen a flagship dongle’s performance being very close to its flagship DAP, but I probably haven’t heard it come that close, like I’m hearing it in S3 vs GT2.  The S3 has a very similar technical performance and tuning to GT2.  It goes beyond just sharing the same Lotoo DNA, with the same effortless delivery of neutral, natural, transparent sound, a big, expansive, holographic soundstage, and very precise layering and separation of the sounds.  One thing to note: after very close listening with multiple back-and-forth comparisons, I’m hearing the GT2’s note density to be somewhere between the wired and wireless performance of the S3.  It still has the same airy, colorless reference sound I hear from the S3 wired connection, but with a bit more note density and texture from the S3 wireless connection.

Would S3 substitute for GT2?  It’s an interesting question.  GT2 is still a portable, standalone source with high output power, and you don’t need a smartphone to play music.  But if you catch yourself using GT2 more often paired up with your smartphone for streaming, I think you will prefer a more compact “GT2” version in the form of the S3.  I know many people switch to standalone, non-Android DAPs for pure audio performance and to avoid email, text, and social media notifications.  But many also prefer dongles on the go, when traveling, commuting, and don’t want to drag another brick with them.  And that’s where the S3 comes into the picture as a great alternative, or maybe a replacement for your current source. You still need to equip your source with an LTTP transmitter, such as WT-2.  So, in a way, you need two dongles to make that wireless connection: WT-2 and S3.  But still, the WT-2 is very compact, and the S3 with a wireless connection can deliver very impressive performance on par with GT2.

S3 vs S2 (released in 2021) – relative to the S3, the S2 has a narrower soundstage and a more intimate presentation.  The tuning of the S2 is also neutral, but it is warmer and smoother, with fuller body, a less layered sound, and a smoother top end, being very close to the PAW6000 DAP.  The S3 is neutral, but it has noticeably better detail retrieval, less coloring, and better layering and separation of the sounds.  As a side note, it made no sense to compare the S3 to S1.

With other popular dongles.

S3 vs NiPO A200Pro – both of these dongles have very similar technical performance, with a huge, expansive soundstage, holographic-level imaging, a super-black background, and very precise layering and separation of sounds.  Where they differ is the tonality.  A200Pro has a bit deeper sub-bass rumble and more treble crunch up top, while the S3 remains neutral and natural across its entire FR.  Also, despite both having internal batteries, they have different feature sets.  The A200Pro is wired-only and has a slightly larger footprint.  S3, while also having an internal battery, is thicker and bulkier but offers wireless connectivity, though you will need an LTTP transmitter to use with your smartphone.

S3 vs iBasso DC Elite – similar to above, both of these dongles have very similar technical performance, with a huge, expansive soundstage, holographic-level imaging, a super-black background, and very precise layering and separation of sounds.  Where they differ is, again, the tonality.  Elite has deeper sub-bass rumble and stronger mid-bass impact, offering a punchier low end, while at the other end of the spectrum, Elite has brighter, more energetic treble with more crunch.  The S3 still holds its neutral, transparent, natural, resolving stand against Elite.  They also have different feature sets: Elite has no internal battery, is more portable, and focuses purely on playback with no additional settings.  The S3 can be used wired or wirelessly and has many more settings, including various sound effects (if that is something you are interested in).

S3 vs L&P W4 – in this comparison, you will hear more technical and tonal differences.  While I consider both to have a holographic level of imaging for sound placement in space, the S3 soundstage expansion is wider and more open, whereas W4 is still narrower, creating more intimacy in this comparison.  The W4 tonality is warmer, smoother, and more colored than the S3’s neutral, transparent tonality.  Relative to the S3 tuning, W4 takes a warmer tuning in the opposite direction from the more revealing DC Elite tuning.  As a result of W4 being warmer and fuller-bodied, it has greater note weight and denser sound, while the S3 has greater transparency and better layering and separation of sounds.  Furthermore, the W4 is a smaller, battery-less dongle, while the S3 is larger and bulkier and can be used wirelessly.

All four of these dongles are at the top of their game with unique tuning and functionality.  What it comes down to is your preference for the pairing synergy with your IEMs and headphones, and whether you want to color your sound or keep it neutral and transparent.  The difference in functionality will also play an important role depending on how you are planning to use these dongles, in wired vs wireless modes, with S3 being the only one out of these 4 offering a true lossless wireless performance on par with the wired connection.

Conclusion.

Perhaps some might wonder whether it was worth waiting 5 years for the next version of Lotoo’s S-series DAC/amp dongle? As I mentioned in the intro, Lotoo is not one of those companies that spoils us with frequent releases. Anticipation for a new DAP usually runs high. Given that GT2 was released 2 years ago, I wasn’t even sure whether we should expect a new PAW6000 next or something else. Therefore, the S3 announcement came as a big surprise, especially given how closely it is tuned and how it performs compared with their GT2 flagship DAP. Being able to use it both wirelessly and via cable was another pleasant surprise, especially after I learned it would support their lossless wireless LTTP protocol. I do have to admit that the lack of regular Bluetooth support and the requirement to buy an LTTP dongle puzzled me at first. But once I started listening to the S3, comparing its wired and wireless sound quality, and then added the GT2 to the mix, I came to appreciate this new Lotoo release much more.

The S3 is not just another dongle for connecting your wired IEMs to a smartphone via a USB-C cable, or for cutting the “umbilical” USB-C cord between the dongle and the phone via a wireless connection. To my ears, the S3 delivers a sound that resembles their flagship GT2 DAP, with reference-quality, uncolored, resolving, natural tonality. It has strong technical performance, with a huge soundstage and holographic imaging, including effortless, precise layering and separation of sounds. The device is powerful enough to drive demanding headphones and remains dead-quiet without any hiss when used with very sensitive IEMs, even at super-high gain. And despite the need to buy a wireless LTTP transmitter, such as the WT-2, you do get truly lossless wireless performance on par with wired connections, with few compromises. Is this the best dongle currently available on the market? As I always say, there is no such thing as the best, just what is best for you, based on your feature and design requirements, pairing synergy with IEMs and headphones, the music you are listening to, and your budget. So, if you fancy a neutral, transparent, resolving, non-analytical, natural tuning and don’t want to carry a DAP brick, the Lotoo S3 makes a great choice as a compact wired or wireless DAC/amp dongle to turn your smartphone into a high-end flagship-quality DAP.