Fosi Audio SK01 Headphone Amplifier Equalizer Preamp with Bass Midrange Treble Tone Control and Loudness Compensation Portable Class A Analog Amp with 3.5mm 6.35mm Jacks

I bought this to add life and depth to a portable cd player that works great but sounds a little flat, and struggles to drive higher-impedance headphones. This works perfectly, adds a lot more power/volume and the tone controls give a good range of eq. The "loudness" button is also very useful at low volume, the sound quality of my cd player is greatly improved with this little device. Couldn't be happier with it. Also does the same for phone/tablet. Build quality is excellent, feels very solid and durable. Small enough to put in your pocket, if a little heavy.

Fosi SK01 delivers on many fronts, with its versatility. The sound quality is very smooth too. I've used it with my bass heavy Soundcore boom plus 2 Bluetooth speaker, it literally tames the bass, and the ability to also increase/decrease midrange and treble frequencies too makes the speaker sound stupendously awesome, and a joy to listen too ! Results are also very good on my mobile phone, TV and DJ controller. Not so good on my laptop, but that's purely because the laptop manufacturer has skimped on quality audio components, having said that it still sounds great, but with less oomph. All the knobs, buttons and inputs/outputs just work like they should, and my Sennheiser headphones have come alive too. No need to have the volume up too loud either as it delivers great audio quality. Battery life is dependent on how hard you use it, but satisfying all the same. The warning indicator light above the treble knob will flash when the battery power is running low, and show red when you're charging it up. When fully charged, the red light will go out. You can continue to use it when it's charging, but I think it's best to make it charge undisturbed, to prolong the overall longevity of the battery life. The light below the volume knob will flash faster when the volume is too loud, another nice touch My lower quality music files are also enhanced by the Fosi SK01, as I take advantage of the ample frequency ranges provided to tailor and boost the sound where ever it is needed. The sleek rectangular shape is aesthetically pleasing to look at and solidly built, the bottom of the knobs are almost seamless against the main body of the amp, which eliminates dust getting inside I'm not a headphone amp connoisseur so can't compare, and no doubt there are brilliant premium models out there, costing mega bucks ! But Fosi Audio have come up with a winner, that covers many bases, delivering real quality at a price point that doesn't break the bank. One more point… I wish it had Bluetooth capability, to combine with my Bluetooth speaker, to eliminate using leads connecting them together, when I'm out in the public domain. Overall, though, a very well-thought-out product that deserves the accolades and positivity lavished upon it. Well done Fosi Audio 💯 🔥🔥🔥🔥🔥🔥😁

Love listening to my DSD music on my Cowon Plenue L DAP. However, i have always liked a little mess with equaliser settings just to get the sound i like. With flac files, the Cowons jet effect equalizer is fantastic, but you cannot equalise DSD files. So bought this Fosi. I have had Fosi stuff in the past and know it is decent and getting better all the time. They tend to develop stuff where other companies do not seem to go. This has the power to feed my Sennheiser HD800S headphones without a problem. The treble, mids and base settings allow you to change the sound to your liking. Sounds great and easy to use on the fly. Each charge seems to last also. Recommended.

Nicely made. I'm using it as an inline equaliser for my TV sound to improve speech intelligibility. The mid adjustment is very handy as is the loudness control. I've tried several other equalisers with more bands but went around in circles trying to get it right so decided to try something simpler. Very happy with this.

I use headphones when listening to videos on the internet and have a good quality set of headphones for that purpose. That being said, my computer motherboard's output was not adequate to drive the headphones well enough. This wee headphone amplifier gives my headphones that extra bit of power to improve the volume with dedicated controls to boost the treble, midrange and bass to suit my taste. A really nice bit of kit for a bargain price. Highly recommended for my type of application. Five stars.

Very good dac sounds Great would recommend

Have had to edit this.... initially it was great....a few months on and it's just died..... been using it fine and the sound is fantastic..... but woke up this morning to find that sound is on for about 60 seconds, then off for about 60 seconds, then back on..... totally useless doorstop now. One to avoid. Obviously made from cheap components that die quickly.

It is a good addition to what I have. Giving a way to tune not only the bass and treble but also on the mid. The price is acceptable considering that it is a cleaning-sounding amp and powerful, too. Able to drive my HD650 effortlessly. I always perfer these volume knobs than the key-presses and these work very well. A happy purchase overall.

I’m using the Fosi Audio SK01 together with the Fosi Audio DS2 and my Beyerdynamic DT 770 Pro 80 Ohm, and the combination sounds fantastic. The SK01 has more than enough power to drive my 80 ohm headphones with ease. The sound is clean, dynamic, and detailed. Bass has great punch and control, guitars sound clear and energetic, and vocals are natural without being recessed. It really brings my music to life. The tone controls are a big advantage. I can slightly boost the bass when I want more energy, or adjust the treble for extra clarity depending on the recording. It’s simple but very effective. Build quality is solid, the knobs feel smooth, and it looks great on the desk. For the price, the performance is impressive. If you’re building a budget-friendly but high-quality wired headphone setup, the Fosi Audio SK01 is absolutely worth it.

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Tengo varios amplificadores de auriculares, entre ellos alguno de sobremesa, con componentes discretos y en clase A y algún otro de triodos single ended. Pero desde que tengo éste, no he vuelto a usar ninguno de los otros. La versatilidad de poder ecualizar graves, medios y agudos y aplicar loudness (que por cierto está muy bien logrado) hacen que sin importar que cascos utilice, siembre encuentro el balance tonal adecuado. Muy contento con él.

DAC FOSI SK01 Qualité et ergonomie excellente, fonctionnement OK, ne nécessite pas d'alimentation séparée (prise usb-c in pour data et alim). Entrées usb c ou optique Sorties : optique et line out audio (même prise), plus jack 3,5 mm et jack 4,4 mm Attention ne fonctionne pas avec les iPhone lightning , même avec le connecteur USB-3 Le gros bouton ne possède pas de repère : j'ai mis un point blanc avec un feutre indélébile

Ich liebe das Ding. Habe es seit über einem Jahr in Gebrauch. Endlich mal ein guter Ausgang für Kaufentscheidungen anhand von Youtube und Rezensionen, klassische Hifi und Technik Magazine sind ja leider verschwunden. Eckdaten: - PC mit einem sehr guten Onboard Soundchip *schlagmichtot, hab ichgerade nicht exakt im Kopf* (man mag kaum glauben, auf wievielen Platinen noch der selbe `90er Adlib Chip sitzt) - Output: Sennheiser HD558 oder HD 490Pro Ergebnis: WUFF! Ich hatte ursprünglich nach einem kleinen Vorverstärker für den HD 490 gesucht, war mir aber nicht sicher, ob ich in dieser Konstellation überhaupt einen bräuchte. Ich will hier nicht mit Ohm um mich werfen und welche Quelle zu welchem Ausgabegerät, eigentlich bräuchte es ihn nicht. Aber, das Ding macht genau was es soll. Glasklar, und selbst dem HD558 ermöglicht es neue Spähren und Dynamik. (Kurzer Einschub: Ich bin kein Sennheiser Fanboy, bevorzuge aber diese glasklare und ausgewogene Wiedergabe in den Mitten und Höhen. Problem bei Sennheiser war immer, dass der Bass, besonders bei offenen Modellen extrem auf der Strecke blieb. daher der Kauf des SK01, eigentlich um einen kleinen Equlizer zwischenzuschalten. Der HD 490 hat das nicht nötig, aber auch der profitiert enorm.) Ergebniss: Wuff! Glasklar, ein deutlicher Zuwachs an Dynamik (ist natürlich stark abhängig vom Impedanz Bereich des Endgerätes), klein wie zwei aufeinandergestapelte Schokoriegel nur 5x so schwer + dass, das Ding nen Akku hat, habe ich erst vor Kurzem auf reisen im Hotelzimmer festgestellt: Handy->SK01->Kopfhörer: TRAUM! Für mich kein normaler Usecase, aber gut zu wissen. Aus meinem home Setup, auch nach Vergleichen mit diversen anderen Kophörern, nicht mehr weg zu denken. Würde das Ding immer wieder kaufen. Ich weiß, das war jetzt hier ein bisschen zu nischig, aber ich hoffe ich konnte dem ein oder anderen damit weiterhelfen.