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Question: on a full charge, does the amp last for hours of listening or is it a shorter charge, like an hour or so?
Document: I walked 5 miles yesterday with the entire package - AKG, EiiO6, L9 LOD in the GPS case and it was bliss! !The EiiO6 manufacturer's claim of 10 hours use per charge is true for this brand new unit. It took approx 45min-1 hour to charge from a USB port. I wonder how long the lithium battery will last ... anyway I am endorsing this model because of its performance and low replacement cost.
First off I will say that I have much experience with Fiio products. I've usedan E5 for years and been happy with it. Thought I'd try the E6 because of it'sextra features. After using it I'm very disappointed with the battery life. Iuse it for exercising and work out for anywhere from 1 - 3 hours sometimes. Anythingover 1 hour is very iffy as to whether the battery is going to last for me. TodayI worked out for 1.75 hours and it died after about 70 minutes.
The Good: This thing does what it says it will do and sounds pretty awesome. You will not use the full volume without doing ear damage, unless you already have ear damage. It successfully takes the underpowered Razor Maxx output and delivers excellent sound, while improving the range (bass. )The Bad: I don't know how they define "normal use", but 10 hours is a pipe dream. I'm lucky to get an hour out of it at perhaps half its volume potential.
After reading the other reviews I was pretty exited to buy this amp. But after charging the amp and putting it to use, it didn't last more than 20 seconds before shutting off. I then decided to charge it for a longer period of time hoping it would make a difference and it was just a glitch or something... The second time it lasted a little longer than 20 seconds after charging for a few hours.
Besides it's plastic (ugh) construction, this little amp is a huge step up from the E5. It's EQ settings are terrific, and it's compact design makes it perfect for going anywhere. Battery life is about 10 hours on a full charge, and it has a very small amount of "hiss" compared to the E5. It's still there, but you won't notice it unless nothing is being input, and you're at a high volume.EDIT: It was good, whilst it lasted.
I like this little amp. I use it because im hard of hearing and instead of buying expensive hearing aid headphones that break i tryed this. it makes it louder, bass better, and lessens all the fuzziness that you get with some headphones when you play them full blast. it works great, the batter dies after a few hours, but charges super quick. 5 stars!
I usually leave it over night or charge it on my car as I drive to places, my usually driving length is 40 minutes. It last pretty long, I didn't really test or time it but I've been on campus with it on for roughly 5 hours at least.
I used a few headphones, in my last few years. Klipsch Image Ones, Skull Candy, and a few others...but when I purchased Bose  AE2i headphones, with this amp...well worth it!! I listen to my headphones most of my 10 hour days. It keeps my sanity, while I work at a factory. This amp, for the money, makes a REALLY nice upgrade in the sound quality. The three settings, are really nice, for different people.
Each charge last for approximately 10 hours of audio performance (I have confirmed this). Instead of recharging it via AC, you simply connect the supplied USB charging cable to any computer USB port and recharge it that way. A red indicator light will go out once it is fully charged--roughly two or three hours (my guesstimate since I did not actually time it).
Order placed on: March 24, 2013Delivered On: Friday, March 29, 2013Dead on: Sept 2, 2013; 2:32am.Pass on this! Will no longer hold a charge for 8 hours or even 8 seconds. The last few months, I have not been able to use any of the sound enhancement features, as the sound would distort. I figured it was starting to crap out. Ugh.The battle of decent sound that doesn't disturb others, continues!
Answer: The specs say it should last about 5 hours, but it's even better than that for me. With my headphones (Bose AE2) on the "blue" setting (bumped-up bass, i.e. high power output), the amp will last a full work day (8 hours). So, for me at least, it's "hours of listening".