Green Day have gone "Back to Basics" on their new album.

The 'American Idiot' hitmakers are working on songs to the follow up of their 2009 LP '21st Century Breakdown' and decided to experiment in the recording studio with their old equipment - with disappointing results.

Frontman Billie Joe Armstrong said: "It's just been songwriting right now. Instead of doing it later on, we decided to start doing stuff now. ... It's all back to the basics again. Just getting in a room together and starting jamming.

"We set up all of our old gear, which was like an experiment. We set up all of our equipment from 1992, and we sat in a room. We got in, and I was like, 'Come on, guys, we're getting back in!' and I start playing and go, 'This sounds like s**t!' Everything sounded so bad."

Bassist Mike Dirnt added: "Me and our drummer Tre Cool were looking at Billie going, 'Really, you've got to pull out that POS amp?' I mean, it really sounded like c**p."

Although they have started initial recordings, the group admit they have no idea how the finished album will sound.

Billie told MTV News: "It's still really early. We've got to start translating the songs and explaining the songs, and the next step will be arguing about the songs."