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

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 💯 🔥🔥🔥🔥🔥🔥😁

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.

just received this morning, setup was easy, usb from P.C, which carries signal and 5v power, optical from TV used as monitor. Headphones sounded great whether from 4.4 mm balanced or from 3.5. I attached a 3.5 mm audio cable, from the aux out on rear of unit, to my active speakers and all good there too. Controls on top of unit for gain, high/low, a mode selector for optical or USB input, and a volume control knob, with an array of led lights to indicate bit rate and mode. Small yet solidly built. All the connections I need for desktop system are there and at a reasonable price.

Feels like a quality produce, Aluminium construction, easy to set up, the mute on the dial is a nice touch. Runs very nicely from a fairly basic Optical PC setup to some Beyerdynamic headphones, big improvement across the board.

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.

I bought this after being underwhelmed by my active speakers when using the sound output from my monitor. Music played sounded flat & tinny on my desk. I knew my speakers were capable of far more so I decided to take a chance on this product despite it costing more than my speakers, mainly due to all of the positive reviews. It was worth every penny. My speakers finally sound as good as they should. The bass has a lot more punch, and I love the control over the mid & high range frequencies. The product is small and compact enough to have it hidden under my monitor stand. I would definitely recommend the the SK01.

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.

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.

This is my first ever headphone amp and it is amazing! I know it sounds cliche but wow, i really do hear sounds i never heard before. I have been using this amp excessively for 2 days since i got it. This amp includes mids, so its like having a 3 band equalizer built in and it has an internal battery so its sort of portable. I have been using this amp with my sennheiser hd518 and hd558, yes i know they are old headphones but theyre good headphones and even better with the amp. Today i fed them through a pair of edifier m60, firstly i set the internal equalizer of the speakers to flat then using the amp to change treble, mids and bass to my liking. The sound is awesome, i just wanted to sit there and listen to every song in my collection.

ممتاز جداً شغلي سماعات فوق ال١٥٠ اوم بكل سهولة

Very nice! I use this DAC as a external sound card for two computers, by plugging it into a USB hub into a KVM switch. It takes control of the volume output, so volume control for both the Windows and Linux machine is controlled with the dial. Tweaking the output volume in the Windows OS has no effect on the output volume, however on Linux the OS volume seems to control the gain a bit. But I just set the volume to something which sounds undistorted, and I got the same volume in both OSes. Don't notice delay in sound either. Music playback sounds great. Perfecto.

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!!!