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 3.5mm 6.35mm Jacks

I am SO happy I bought this! What a powerful little device. I was scared about the price tag for (in my mind) such a simple product, but I couldn't have been more wrong. The value I've gotten from this equalizer makes it one of my favorite things I've bought this year. I'm going to feel so naked if I don't have this thing as part of my PC setup from here on out.Easy to use, no installing any software, looks sleek and fits perfectly on my desk right next to my interface. I highly recommend grabbing one if you're like me and don't want to alt-tab to another program just to equalize your sound when that heavy bass dubstep comes on.

Exactly what I was looking for. I have a classic iPod, and I just wanted a good EQ for my Heavy’s headphones. This makes the music sound awesome! Great little EQ, durable, easy to use, and I love that it has a built in battery so it doesn’t have to stay plugged in. Looks good and good value for what it does. Highly recommend!

The best sounding results were found when streaming movies or from .FLAC audio files when pairing this unit with a SK02 USB DAC using its Aux out. I found that using the SK02's AUX/OPT 3.5mm connect jack (which also doubles as an optical ouput jack as well) gave a higher output level than the headphone jack. Using a 12" long 3.5mm male TRS to 3.5mm male TRS from the Aux Out of the SK02 into the Line IN of the SK01 provided the best undistored output when connecting a 3.5mm to RCA splitter from the SK01 Line out to a 75WPC Amp. This preamp's mid range control provided a lot better tone than the K5 pro that did not have this mid adjustability. An added feature is its internal battery that is charged from the USB-C connection.

3.5 mm output connection does not work correctly. One headphone doesn't play through the left side unless the jack is pulled out halfway, the other headphone doesn't work at all unless you press the jack in very hard and rotate it just so. Works well when it works. UPDATE- the company has offered to send me a replacement. Very easy to deal with.

All I wanted was to bring out the subtle sounds in the accompanying music mix without mushing up the vocalist's track. I use Moondrop Blessing in-ear-monitors (earbuds) ...https://www.amazon.com/gp/product/B0C1ZBTD2Vand a conventional CD player (KLIM Discover)...https://www.amazon.com/dp/B0BRXH9L84with an upgrade cable (GUCraftmans cable with two pin connectors to match the Moondrop Blessing earbuds)...https://www.amazon.com/gp/product/B08N6211FFI didn't want a DAC (Digital-to-Analog Converter) or a combo DAC & Amplifier because the DAC/Amplifiers require RCA inputs or OPTICAL inputs. My CD player has only one type of output: 3.5mm (for earphones).Instead, I just wanted a headphone amplifier that would sweeten the sound of my CDs. I wanted to use my CD's player's headphone output jack (standard 3.2mm headphone jack) to connect the CD player to the Headphone Amplifier's 3.2mm input. I would then plug in my earphones to the output headphone jack on the amplifier.This amplifier is special because you can adjust the sound by manually altering the tones for bass, mids, and treble. Or, by pressing a simple button, you can bypass all tone adjustments and just let the amplifier do all the work of adjusting the volume of the track. Even without the tonal adjustments disabled, music still sounds better than without the amplifier.There are two more adjustments that can be enabled or left alone. The manufacturer describes them as follows: "Diverse Capabilities: Instantly restore original sound with the one-click tone-defeating button (I explain that one above); Immerse yourself in music during the quiet hours using the loudness function; Tailor the gain level to accommodate headphones with various impedances through the gain level switch."The loudness function is a stumper for me. I hear no difference when I press the button. I am NOT very responsible when it comes to the volume streaming into my head through the earbuds. I like it loud. I imagine the loudness function is used to keep all sounds under a certain decibel. Or, enabling the function might make the quieter sounds louder, relative to surrounding sounds. It might a "limiter" of some sort.Your own headphones or speakers or in-ear-monitors should have their respective impedance ranges documented. But whether I set the amplifier gain control to 0 or to -10, I don't know which I should choose. Depending on the content on a particular CD, I choose either setting to determine which setting sounds best.The exact title of this amplifier is "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 3.5mm 6.35mm Jacks," but don't let the title throw you. Yes, an electric guitar player can use this amplifier to monitor his guitar-playing, but it can be used for just about anything that you would want to make louder and sweeter...like your collection of CDs!The Fosi Audio SK01: https://www.amazon.com/gp/product/B0CF1WL1V2

its dope

This can be used as an amp or preamp for headphones. I have a headphone tube amp with some Sennheiser HD820 headphones and my amp was just not enough to really drive the Senns. Once I added this preamp they finally came alive; they sound amazing. This also has a chargeable battery, so it doesn’t have to be plugged in, which makes it portable. I plug it in to my reel to reel and use it as a headphone amp and it sounds great. This is hands down the coolest thing I’ve purchased in a while.

Arrived on time, works well. Happy with my purchase.