The original tapes for The Beatles‘ Please Please Me are becoming “sticky” and “sludgy” – so much so that Abbey Road engineers working on the new Beatles In Mono vinyl set have been forced to make a new master for the album.

As mastering engineer Sean Magee explains in the new issue of Uncut, out today (August 26), the glue on the original master tape of The Beatles’ debut album was seeping through the layers of the tape, making playback difficult.

“The tape was playing and it left a sticky sludge on the playback head,” says Magee. “Which isn’t very good: it places the tape under tension and potentially induces friction. We thought rather than have it do that, we thought we’ll make a new one.

“We used that tape and transferred it. Playing one track at a time wasn’t an issue but if you played five at a time, you had a sludge on there. It’s a historic tape, it’s pretty old, and it’s affecting the sound.

“You gum up the heads, all the high frequency starts to disappear, so you transfer the tracks, one at a time, analogue to analogue, then put in some new leader tape to get the gaps right and we now have a cutting master for this new boxset.”

The Beatles In Mono is reviewed in the new issue of Uncut, dated October 2014 and out now.