O'Connor considered himself a guitarist more than anything else, claiming that many of his songs would begin on a guitar, even if there was no guitar in the final recording. He played a range of different guitars including 6-string steel string guitars, classical guitars and 12-string guitars. O'Connor mainly played Taylor Guitars, although he claimed that his favourite guitar was a hand-made Mirabook, built for him by Gary Albrecht, admitting, however, that he favoured a 'very special' Takamine Guitars Sante Fe classical. O'Connor's secondary instrument was the piano, in particular, a Yamaha C4 baby grand piano. O'Connor claims that this is where most of his composing came from.