SINGXER SA2 Class A Fully Balanced Headphone Amplifier – Refined Raw Electricity Distributor
Singxer SA2 is a $629 USD Class A Fully Balanced Headphone Amplifier and Preamplifier with the highest driving power we’ve seen in a headphone amp of this size so far. SA-2 is a huge upgrade over the previous generation and today we will explore how it sounds like, how it matches certain hard to drive headphones, as well as how it compares to other headphone AMPs including HIFIMAN x Goldenwave GA-10 ($1599 USD), Erzetich Bacillus II ($934 USD) and Aune S17 Pro Evo (799 USD).
Introduction
Singxer is not a new name for us, and they are a mystique company that produces something new very rarely, but when they do release a new product, it is always a banger. I love how you can always rely on Singxer products to be fun, enjoyable and above everything, reliable. Singxer products are available in hifi and Chifi sale channels, Aliexpress and Amazon.
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Product Link
Amazon – https://amzn.to/4teiRIR
Aliexpress – https://s.click.aliexpress.com/e/_c4MO5V5d
Build Quality – Design
Singxer designed SA2 as a huge upgrade over the original SA-1, so much so that you will be compelled to upgrade once you learn how they improved in every aspect of the original Amplifier. We actually did review the Singxer SA-1 V2 quite recently and we liked it a lot, so you should head to that review and read about the original to better understand where we’re coming from.
Total output power has been increased from the 5.5Watts that Sa2 could deliver to 10 watts in a 32 OHM impedance, and 15 watts for a 20 OHM impedance, with Sa-2 supporting headphones down to 8 OHMs minimum impedance. While most manufacturers don’t usually quote the minimum impedance, below 10 OHMs, most will enter clipping as the sound will feel more like a short circuit for the amp down so low.
For hard to drive headphones, sinxger optimized the circuit for ultra-low distortion even at max power output. To achieve this, the company enhanced the thermal management with a solid copper clock and aluminum alloy heatsink, and they also reduced the output impedance boosting current drive for a higher slew rate and impact. Furthermore, Singxer gave SA2 an optimized PCB routing with adjusted DC bias circuitry, added DC servo design and incorporated GND / Lift mode switch. The unit is identical for USA, Europe, China and UK, only the included power chord differs.
At its core, Singxer Sa2 is a true quad-channel, fully independent all-discrete Class A amplifier. It is pure analog and has complete elimination of EMI, using a proprietary Class A architecture. Final output employs a multi-stage current amplification, resembling the architecture of high-power stereo amplifiers. Each channel uses two pairs of ON semiconductors with a 4A drive current in parallel output. This ensures a low internal resistance and high output power. Sa-2 also has protection against overcurrent, overheat, short-circuit, DC protection, power-on delay and instantaneous output relay disengagement during shutdown.
Subjective Usage
It is very easy to use SA2 as a headphone amplifier or preamplifier. This is thanks to the rather simple setup, you just plug in XLR, plug out XLR, or a headphone in the headphone jack. There isn’t much more you need to do to make it work, although there are settings on the belly of the amplifier which allow you to fine tune it.
Those switches at the back can tune the gain level for SA2, and this will come in handy for powering certain headphones, although as they are gain and volume switches, unless you find a pair of headphones that require it, most will sound better with all of them as it comes from the factory, which is low gain. Overall, SA2 is an excellent choice if you need a reliable preamplifier or headphone amplifier, as it stays quiet. What does not stay is fully cool, as it does warm up a little, but it does not run hot either, even if stressed, so it is generally a top choice.
While SA2 is not exactly made for IEMs, considering the extreme driving power it has, it is interesting to note that it has no audible background noise, hissing and distortion is minimal even if driving IEMS and complicated loads like ultra low impedance IEMs. Ultra high impedance headphones are also driven well, which is surprising. I like that SA2 works beautifully as a preamplifier and volume control for another setup, and it is so good at this job that it introduces zero noise in speakers, even with a solid state amplifier like Keces S300+ which is sensitive to sourc enoise and has a high driving power.
Sound Quality
Pairings – I have paired SA-2 with both IEMS and headphones, the listy including most of the recent models that we’ve reviewed, namely Lily Audio Genesis One, Raptgo LEAF D01, Palma DHS-1, KBEar Cepheus, Crosszone CZ-10 Enhanced, Erzetich Thalia, TinHIFI T7, NFAudio NE4, Sivga Peng, Crosszone CZ-8a Enhanced, Tangzu TianPeng, Soundz Flame, YanYin Canon PRO, Dunu Vulkan 2, Letshuoer Mystic 8, Moritz Aura, HarmonicDyne Romantic, Hiby Digital Yume, HIFIAN HE600, HIFIMAN Audivina LE, HIFIMAN Ananda Unveiled, Westne Mach 80, BQEYZ Winter II, Fosi Audio IM4, Aune AC55, Oriveti Bleqk PureCaster and Noble Knight.
Singxer designed SA-2 with a versatile usage scenario in mind, it has both enough power for very hard to drive headphones, but also exceptional control and very low distortion, but also very low noise, perfect for sensitive IEMS. You cannot really hear any hissing or background noise even with the most sensitive IEMS in the world, so it is perfect to have on your desk. While normally, volume control would be an issue, it has an interesting curve that allows you to finely adjust the volume at the early parts, so it will not get loud too early.
Overall Signature – Singxer SA-2 will immediately sound different from any amplifier you have heard. It has a certain amount of bass that just feels natural, it gives music weight, tactility, and makes all textures audible and easy to feel. Bass is a focal point, but to achieve it, it pulls back the voices slightly, so it will cause you to increase the volume slightly, which will in return make the bass even louder and more abundant. Treble is sharp and detailed, airy and bright, which complements the darker bass quite nicely, resulting in a highly engaging tuning that puts you right into action. This is a slight departure from other Singxer DAC AMPs and AMPs that used to sound smooth and laid-back, as SA-2 is a powerful, vivid sounding source that is interesting and lively.
Bass – At its heart, SA-2 is a powerful, bassy amplifier with a bold deep-end, but words cannot really describe how much backbone and weight it puts into each musical note. It feels like SA2 not only emphasizes every single note, but gives actual presence to instruments, and this is similar across all music styles, metal, rock, EDM, everything has a powerful kick and deep punch. SA-2 is quite unique for how much it can emphasize the entire low-end frequency range. This being said, it sounds bloomy and can be a bit dark at times, but it is not veiled nor does it go overboard, and this is the interesting part, it has utmost control, can deliver that blow but also recover from it, keeping rhythm contrasty and distortion very low.
Midrange – With a slightly recessed vocal range, SA-2 will make you reach for more volume, which further emphasizes the bass as it can feed more power and in return more kick into each headphone and IEM it is powering. This same effect happens when driving speakers too, if it is being used as a preamplifier, but to a slightly lesser effect as a preamp it is more linear – neutral. Female voices are sweet and vivid, and thanks to a slightly elevated upper treble and treble, it can render a perfect tone for ACG, and female-led pop songs. I find it an absolute delight for enjoying
Treble – Top end is rather powerful, extended and vibrant, giving music a strong contrast, resolution and steering SA-2 away from sounding too dark and bloomy. Instead the main signature and tuning feels vivid, slightly V-shaped, powerful and personal.
Dynamics And Textures – Singxer SA2 is a very dynamic and engaging sounding amplifier, which is a bit different from the previous amps the company made, which were all on the relaxed, smoother side of things. This being said, textures are truly the unique part of SA-2, as it presents a really bold, thick and heavy texture that becomes tactile. With a basshead pair of IEMS or headphones, you hear textures in your head, but not just bass, but guitar textures, piano textures, SA-02 really renders all micro bits and parts of a texture. I personally love how SA2 sounds and find it to be perfect if you want a heavy experience for your tracks. This works especially well for EDM, Pop, Rap, and modern music, especially music with a synthetic element to it.
Loudness Saturation Gradient – I was impressed by how the loudness saturation gradient turned out. Starting with the volume gradient, you have a lot of control early on, so you can use SA2 with IEMs, but later on, volume grows quicker, perfect for headphones. It has zero distortion even if pushed close to its maximum, but it has a nice power voltage saturation curve, which creates a punchy, interesting sound, with a focus on control, low THD and only providing volume when the power backbone supports it.
Soundstage – Singxer made SA-2 with an interesting potential, as it can create a huge soundstage, both thanks to the way it pushes voices slightly away from you and in the back, creating potential for space, but at the same time bass is always in your face, and treble is also closer to you than with most sources, so it emphasizes width and depth, space for the midrange, most instruments, but keeps exciting elements in the treble really close to the listener and bass is always the leading factor in each song SA2 is playing. It has a very strong instrument separation and layering, creating a well-defined image of each song, very enjoyable with both more musical and more technical styles. It will always emphasize the technical side of a headphone or IEM rather than downplay it.
Comparisons
Singxer SA-2 vs Aune S17 Pro Evo (799 USD vs 629 USD) – Functionally, the two amplifiers are very similar, both need a DAC, both have a functionally similar maximum driving power, although at its absolute max, SA2 has a bit more juice, especially for very needy headphones. Low noise, perfect for IEMS, both are great for headphones too, and both need zero additional cooling, but S17 Pro Evo stays hotter while in operation. Both have a similar line out and preamp function. Sonically, Sa-2 has a heavier nuance, it creates a deeper, more powerful bass, with better impact. S17 Pro Evo has a rolled off treble in comparison, so it sounds darker and bloomier, while SA-2 does not sound dark, just heavy, chugg and powerful. S17 Pro evo is laid-back and relaxed, smooth, while SA-2 is bombastic and grand, wide and holographic.
Singxer SA-2 vs HIFIMAN GA-10 (799 USD vs 1599 USD) – An interesting comparison, GA-10 does not look the part, but it is a tube amplifier, so the maximum driving power is lower than for SA-2, which can pack a much heavier punch. This being said, sonically, GA-10 sounds brighter, more vivid and more vocal, while SA-2 sounds fuller, has a thicker, heavier texture, it creates much more depth, and can reach 20 Hz more effectively, while GA-10 is more neutral, does not focus on the low-end in particular. Treble extension is similar, and resolution is also similar, but the way GA-10 renders details is more natural, while SA-2 renders a heavy, chuggy detail that feels more tactile.
Singxer SA-2 vs Erzetich Bacillus II (799 USD vs 934 USD) – From a constructional POV, Bacillus II is simpler, lighter, and smaller, but has a more bold, countryside design with a large volume wheel at the front and has a class AB design. Bacillus is SE or single ended only while SA-2 is fully balanced. Driving power is similar at max, although SA-2 can produce more useful power for very hard to drive headphones. Because Sa-2 is balanced, it has a quieter background noise level. Sonically, Sa-2 sounds bassier, deeper and has more strength, a more tactile texture, while Bacillus II sounds smoother, more vocal, and has less focus on either treble or bass than SA-2. This being said, both are fairly warm and bassy sounding. I would make the choice based on whether you have and want to have balanced connectors as only SA-2 offers those.
Value and Conclusion
It is clear from the start that Singxer Sa-2 has an exceptional value, it delivers so much power and such a clean sound for such a low price relative to the market that if you’re any bit budget conscious, you have to consider it as your next headphone amplifier, it is simply that exceptional, that crisp, clean and punchy sounding.
Award – While I rarely give awards these days and most products, regardless of the price point simply don’t impress me that much, Singxer SA-2 is unique, it is powerful, clean, has low sonic coloration and it is reliable, so I will be adding it to the audiophile-heaven hall of fame, it surpassed its predecessor and also the overall market with performance for a low price. Singxer SA-2 has earned its place in the Audiophile-Heaven Hall Of Fame for its exceptional sound.
If you decide to go for the Singxer SA2 there will be no end in sight, it is basically the perfect, most interesting headphone amplifier you can buy at this price point, and although boutique options with a different pre or even tube amps exist, SA-2 will deliver control, precision, detail, and power enough for HIFIMAN Susvara, Lily Audio Genesis One, and SJY Horizon, it is basically the perfect match for very hard to drive headphones, and it will keep your pockets full and heart happy.
PROs
- Industrial design with reliable build
- Does not get extremely hot
- Full Proprietary Class A architecture
- Clarity and resolution are over the top
- Driving power is highest you can achieve in this price range
- Excellent soundstage and low sonic coloration
Cons
- Still can get quite hot during usage
- If Singxer made a matching DAC or a DAC AMP, it would be the ultimate combo for desktop listening
Product Link
Amazon – https://amzn.to/4teiRIR
Aliexpress – https://s.click.aliexpress.com/e/_c4MO5V5d
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Full Playlist used for this review
We listened to more songs than those named in this playlist, but those are excellent for identifying a sonic signature. I recommend trying most of the songs from this playlist, especially if you’re searching for new music! The playlists are different for Spotify, Tidal and Youtube, and based on the songs I enjoy and are available on each!
https://www.youtube.com/playlist?list=PL_cjBXGmwSHSdGcwuc_bKbBDGHL4QvYBu
https://open.spotify.com/playlist/5J3oloz8Riy9LxEGenOjQ0?si=979ba4f082414be7
https://tidal.com/browse/playlist/330fd544-8e5b-4839-bd35-676b2edbb3d5
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