MusicNomadAcousti-Lok Strap Lock Adapter for Standard Output Jacks for Acoustic Guitars (MN270)

Q: Does the adapter lock spin on the guitar strap peg?

The adapter fits snugly. It doesn’t spin loosely but can be spun into position by hand fairly easily and it will pretty much stay where you leave it. Doesn’t touch the body of the guitar. Well made item, recommended.

Q: Will this work on a Yamaha A3 guitar?

If your Jack is metric, then yes. These devices Work on all A/E guitars that have a jack replacing the strap pin. Seller may know which model you need. If not Yamaha should or you could just unscrew the strap retainer nut go to a hardware store and find out the size.

Q: expression system 1 taylor 814 ce circa 2004. Will this strap lock work??

I believe all you need to do in your case is change the strap button to the strap lock style.

Q: Will this work with the new Schaller S lock system?

I don't know for sure but it probably will with some minor modification. I got it to work with my Dunlop locks but had to substitute the Dunlop receiver for the button that's on there. It's a really great solution for having a strap lock when your guitar's output cable is where the strap would normally go. It's also very solid.