Bluetooth headphone amp/dac

Happy New Year tweakers!

Has anyone had any success in adding Bluetooth to something like CMoy or O2 amps?

I'd like to use my Grado 125's with my smartphone as a source and thought if I could add a BT module I'd get around the fact it doesn't have a 3.5mm jack.

Any thoughts? Or is this when it's just going to be easier to buy something ots?

Thanks in advance

Michael