'Remember that in the late '70s we didn't have computers, and the telephones were huge,' says Karl Bartos, smiling and sneaking a glance at the iPhone I'm using to record the conversation. Karl Bartos (Berchtesgaden, 1952) was the first member of the so-called classic line-up of Kraftwerk (the one that made the group's most essential albums, from 'Autobahn'  to 'Electric Café' ) to tell Ralf Hütter, the only original member still in the band, that he was ready to hit the road.
This was in the '90s, the busiest decade in Bartos's career, what with all his work with the Electric Music project and supergroup Electronic with Johnny Marr (The Smiths) and Bernard Sumner (New Order). He ended that era in 2003 with 'Communication', released under his own name, including the single '15 minutes of fame'.
Ten years later, he's back with 'Off the record', an album that uses material from the audio journal that Bartos recorded during his time with Kraftwerk. 'It's meant to reintroduce you to the young me,' he explains. 'I took ideas from the past and brought them to the present. What I wanted was to combine these two eras, to re-evaluate my ideas. So the album is 100% old me and 100% present-day me.'
How did you end up with Kraftwerk?
For seven years I played percussion in an orchestra. As a music student in the '60s and '70s, especially as a percussionist, I was very familiar with the work of Karlheinz Stockhausen, John Cage and Steve Reich. When Kraftwerk came looking for me it all seemed to come together.
What was the electronic scene like back then?
It was interesting to work with electronic instruments and with recording equipment. I learned everything about musique concrète. The basic idea of that period was that music could come not only from instruments, but also from the sounds of nature or a machine. When I joined Kraftwerk this became one of the most important concepts: making music with sounds recorded from our surroundings, without ignoring the pop elements.
How did it occur to you to mix musique concrète with pop?
There was something in the air. In 'Summer in the City', by The Lovin' Spoonful, which was No. 1 in the American charts, at the beginning of the song there's an example of musique concrète: a train, a car horn, a jackhammer... In an instant it transports you to New York.
What did you want to contribute to this?
We didn't want to play the guitar because it didn't belong to us. Everyone loved the Beatles and the Beach Boys, but that wasn't our culture. If we wanted to create a powerful cultural discourse, we needed to look around us. Being central European meant looking towards Stockhausen, Pierre Henry, Debussy. We wanted to help heal the cultural wound left by World War II, and we preferred to look backwards, to Metropolis, from Fritz Lang, instead of making Anglo-American music.
Why was the music on 'Off the Record' never released on a Kraftwerk album?
Because we released very few. This was one of the main reasons why I left the group, because I wanted to compose and have my own life. Everything was sealed up tight: I couldn't do anything except Kraftwerk, that was the agreement. The decision didn't have anything to do with music or art. What we were making was fine with me. It had more to do with approaching 40: I wanted to be independent, I didn't want anyone making my decisions for me, I needed to just be myself.
What do you think about the Kraftwerk retrospective at the MoMA?
'The Guardian' invited me to attend one of the concerts and do a critique, but I declined. I think it could make things worse. If everyone rejected my old group it would be terrible for me, because they are, in fact, playing my music. And if the last remaining member of the classic line-up chooses the set list, I've got nothing to say. The objection I've encountered is that it shouldn't be called a retrospective, because a retrospective implies that they'll have the old line-up. It seems like just another concert to me.