Here's the amp we'll be using Amazon: http://amzn.to/2BSYWZF eBay (ships globally): http://ebay.to/2DiX9uR In this video we'll be making a wireless bluetooth-enabled amplifier so that we can put old bookshelf speakers to good use! Not only is the sound quality fantastic, but it can also go super loud! It's also quite easy to build, and doesn't require any special tools - you can get away with just a hammer, nail, and a screwdriver if needed. Seriously! Full parts list (includes international purchasing links): https://docs.google.com/document/d/1_QFMFvOnSVxPGSobcSUu6EKzrBZ9FB-dHIpLOE9gW3Y Happy building! Oh, by the way, here's the note about the little switches: These switches change the gain mode of the amp. If they're both on, the amp can reach insane(er) volume levels. However, to hit these volume levels without distortion, the amp needs 25v, which is more than our batteries can provide. The amp is loud enough with them off, and it also means that the signal to noise ratio is MUCH improved, so I don't really recommend messing with them.