Make sure you take the batteries out of your Mighty Bright music light before you pack it in your harp gig bag or the light case. Otherwise, you may wind up like me last night finding the light had turned itself on and the batteries were almost dead. I now know you can leave the light on using batteries for 24 hours. Thankfully, the orchestra model comes with a very long cord, and I found an outlet to plug it in.
It’s a sliding switch. How about just putting a piece of electrical tape over it? If you prefer to take out the batteries, it’s not necessary to remove all three. Removing just one battery will break the connection.
Mine has a button that you can push twice to control the light level. One thing about using with the electrical adapter–I find that using it with batts can be a tad crotchety after that. I now have to take the batts out to turn mine off, but that’s okay since I’d be removing them anyway. Would be a problem on an orchestral gig where you needed to turn the light off in mid-concert, though.