Headphone Amplifier Headphone Amp Audio Powered Headphone Amplifier for iPhones iPod MP3 MP4 and Computers

Pros:Sounds great. I recently bought high(-ish) impedance headphones and found that portable devices just didn't have enough power for them, especially at the low end. With this plugged in they sounded great, problems solved... or so I thought.Small. Very small.Very simple. Turns itself on when you plug in the headphone/output side (not the input side).Cons:The right and left channels are reversed! I'm surprised no one noticed that yet. This isn't a huge deal for music, only mildly annoying. But it makes it unusable for movies, and I was planning on using it to watch movies on the plane when I need the volume boost. For that reason only, I returned it.Too small? The side with the USB plug has a 2.5mm jack because a 3.5mm wouldn't fit. It comes with a short 2.5mm -> 3.5mm cable for input, but 3.5mm would've been more replaceable.Also because of its size, it's a tight squeeze to get both the USB and 2.5mm plugged in at the same time, but you can do it.It has a power indicating LED on the 3.5mm side, bug a large plug (like one for a 1/4" -> 3.5mm adapter) will mostly cover it.

Just received this and plugged it in right away. Very happy. I have a set of Bose corded headphones that I could not fully enjoy on flights. They just barely cut thru all of the cabin noise. This definitely boosted the volume. The instructions aren't great nor is the description but, there's only 3 holes. One is clearly the micro usb and the other 2 are input and output. The usb side is the source input. I saw a review that said you cannot plug in the usb and input at the same time. The space is very tight. Just charge the unit before using.

This item truly helps the anemic volume from Gameboy Advance Consoles in the headset jack . I use the volume control on the GB Advance to control the volume in the headset through this amplifier . The other reviews are accurate so reading them would be a good idea . Some USB cables will fit alongside the input cable , but one has to try it to be sure . It will work being powered by the USB while listining too . There is a small red light that illuminates next to the bright blue one . The small , almost invisible , red light goes off when the internal battery is charged . The supplied cable length is perfect for the GB Advance . If one is a bit hard of hearing this item would assist in hearing the audio .I have not tried it in any other equipment .I purchased it solely to hear the audio tracks on GameBoy Movies from the movie converter . The amplification gain is not high but definitely is sufficient for this issue on the GameBoy Console . Too high an input volume will result in distorted sound .For the price , it solved my problem . There seems to be an enhanced Bass Boost in this items audio output .

Does a really good job of not just amplifying but of cleaning up the sound.The design of the power and cable to source is a bit of a bummer but, you can trim the micro USB cable with a razor blade and get it to fit with the source cable simultaneously.

I don’t know what y’all hearing but I plugged this into my iPhone 7S and compared audio signals with and without. No difference! Waste of money.

Works well boosts the sound from my tablet to where I have to turn the sound down

Worked fine for a week or so, then the battery died. Had to modify the USB plug so I could keep it powered up all the time. Sadly, it finally gave up the ghost. Tossed it.

Works well and provides good sound