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

Small easy to carry and it have its own battry if you plan to take it out for a while, at home it made my time with the higher sound and bass tweaking.

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.

ممتاز جداً شغلي سماعات فوق ال١٥٠ اوم بكل سهولة

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.

This unit is sufficient as a resolution to enable me to enjoy clean sound through my Beyerdynamic 770 prox ltd. Headphones. My search began with trying out earbuds, nearly 20 pairs put on trial, and it came down to being no options to suit my needs, that aside, Headphones hitting at the quality of Beyerdynamics, leaves nothing left to be desired except for a purely clean signal. This little Fosi Audio unit exceeded my expectations, I give it a solid 5 Stars for the achievement it does meet well. Though there is some lack in the cleanliness of the signal, which I suspect is caused by a conbination of effects, the source originate from a DAC via bluetooth, transmitting from android. The bit rate is no more than 24bits, which is not Fosi Audios fault, secondly the DAC is connected with cheap generic RCAs to 3.5 jack, which is problematic for obvious reasons. This unit will only reveal the truth about any signal put through it, however it does have control features that add a quality to overlook most issues lacking due to low bit rate. Nice Treble, Middle and Bass controls, effective Tone modulation, Gain, and Loudness functions. Fosi could improve these functionalities as they seem to conflict somewhat with each other if all three are enabled, as there is a diminishing niance that takes effect when all three are engaged. The volume control has an excellent ceiling, and over all it passes a pure signal that takes up the sound stage of the Beyerdynics equal to what isbavailable in the signal being amplified. Conclusion, I'm impressed with the build quality it is stylish, all interfaces are smooth and solid, nothing feels cheap or mass produced. It's form factor is intuitively stylish and compliment any small space. Finally, the Price to quality is a bargain!!!

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