eSynic Professional 16-300 Ohms Headphone Amplifier 3.5mm Portable Headset Volume Amplifier Rechargeble Headphone Amp Aluminium Alloy Headset Jack Amp With Gain Switch for Phones Laptop etc

Works really well. With Phillips headset, best sound I've had in a while!

Sounds very good - used it with a HifiMan planar magnetic headphone - no issues - great price.

easy to use. Volume just not loud enough on my Senheissers

I have a Lenovo Yoga Tab 11 tablet that I bought for entertainment and internet access while traveling. I wanted to be able to share with my wife through headphones and Bluetooth but I was afraid the volume would be too low to hear well on a plane so I bought this unit after reading several reviews.The headphones I bought to use with this device are JBL Tune 660NCs (two identical pairs) and I'm very happy with the results. Both pairs of headphones are now quite loud when turned up.While the device is supposed to work with headphone impedances between 16 and 300 ohms, I'm thinking the lower the impedance the better as far as volume goes (less resistance, more current) as both JBL headphones (as well as a pair of Lenovo Yoga BT headphones I also have) are listed at 32 ohms and there is plenty of volume with them. My wife has a pair of Sony WH-CH520 BT headphones that don't go as loud ad the others but unfortunately, I can't find info on the impedance on them so I have to admit that I'm guessing.At any rate, this amp works very well for my purposes and seems to be built solidly. A couple of things to note in my particulars. First, if using with a Lenovo Yoga Tab 11 tablet, you will need a USB-C to 1/8" phono adapter as this tablet has no phono input. I'm also adding a Bluetooth dongle that can pair with two sets of headphones as this tablet is unable to do so with it's onboard Bluetooth.Time will tell but so far, I like what I hear.

Excellent product and great battery life.

Some of the pics show MICRO-USB. If it gets mentioned in text it says USB-C. I have zero MICRO-USB cords long enough to make it practical. If I had KNOWN it isn't USB-C there ain't no Fn' way I would have bought the POS. After 2 weeks the right channel quit. I got a replacement and it was worse than the first. The sound cuts in and out constantly. I triple checked all connections and nothing helped. Sending this one back for a refund. If anyone has a headphones amp that works please leave a comment (if possible).

Louder volume but no increase in sound quality for me. Was using it as a pre-amp from my dash mount Android Auto screen to my head unit's aux input, but it still didn't sound as good compared to using my head units USB input

Update December, 2021: We were sad when we broke our eSynic amplifier recently. We dropped it a short distance to a carpeted floor, but it landed on the slightly-protuding gain switch and broke the switch off the circuit board inside. Sniff! It worked great until then! We replaced it with a slightly more expensive LCY Portable Headphone Amp, just because it's slightly smaller and has a rounded case vs. the eSynic's angular corners. We hope it works as well!A family member with hearing loss stopped using our TV room completely, because they couldn't understand dialog, even with our excellent sound bar turned up. We added this little amplifier so they can use earbuds and control the volume independently, and it made all the difference! We had built a TV room with an HD projector producing a 100-inch image, because this family member also has impaired vision. We were sad when they still couldn't enjoy the TV room. Now this device makes the TV room a joy for all of us.The battery life is good: If we remember to turn it off, it lasts for at least several days on a charge. We plug it in to charge every few days, and we haven't run it down yet.By the way, we don't have a complex home entertainment set-up. For example, we don't have an expensive A/V receiver. Rather, we use a Zamo HDMI Extractor to split off the stereo audio from the HDMI video source. We use the Zamo's optical audio output to drive the Vizio Sound Bar and the Zamo's RCA audio output and a long Hosa RCA-to-1/8 inch cable to bring the stereo audio to the eSync amplifier at the viewer's comfy chair, so they can control the volume. A long, flat HDMI cable carries the video signal all the way around the room, stapled discreetly to the baseboard and in a concealed channel up the wall to our years-old HD projector on a high shelf.We mostly use a Roku as the HDMI source, but lately we installed Techole HDMI switch to switch between the Roku and a small Shuttle Linux PC for watching Zoom webinars!A few inexpensive components, and we have a comfortable, capable TV room we can all enjoy.