Also available at Radio Shack, where I bought three of them, the Upbeat Boostarro does one thing, it amplifies audio signals up to 10db (decibels). That's what it says it is for and that is what it does.
I work in the film and television industries as a sound recordist and mixer. In the last five or more years, we have seen the large video camera shrink down to much smaller sized video cameras. When I send sound to a camera, there is a headphone jack that allows me to hear what the camera hears, so I can verify that the sound is getting on the tape.
But these newer, smaller DV cameras have very reduced room for electronics, including audio circuits and the sound level coming back to me is often so low, I can't hear what is getting to the camera.
It was frustrating and it wasn't until I worked on the movie Unstrung that the director of photography showed me the Boostaroo. He plugged it into the audio jack, I put on my headphones, someone talked in the mic and he then switched it on. Voila! I could hear. I went out that day to Radio Shack and bought one. And knowing only too well that when you find something you like, it can quickly go away. So I've bought two more since, just to have them. Of course, after buying three I see them here on Amazon.com and at a much lower price.
For what it is made for, the Boostaroo does what it says, it boosts an audio signal up to it's claim of 10 db. Some say it doesn't add that much. I've not measured it on equipment but you can definitely hear the change and it does work. It also adds some noticeable self noise (hiss) to the signal. But that is only noticeable when there is no signal or content.
So, in the infamous words of Harry Callahan, "do you feel lucky?" If you don't expect too much from the Upbeat Audio Boostaroo, it will do exactly what it says it will do, boost an audio signal for you and make your tunes louder.