Review Karl Bartos, a member of Kraftwerk between 1975 and 1990, has long kept a “secret acoustic diary”. And it’s to these various notes he turned when the Bureau B label asked him to assemble this collection of previously unissued early recordings.Initially sceptical, Bartos gradually warmed to the concept. He had a wealth of material spanning 1975 to 1993, stored on a bewildering array of recording platforms. All of these were homogenised via transferral to his current computer.It’s not quite clear from the excellent booklet notes how much Bartos has tinkered with the naked material. Whether he’s simply polished and edited, or whether he went in deep, re-recording and shifting around the internal organs. It’s difficult to judge the level of disguise, given that his studio still houses all the original equipment.There’s a subtly menacing edge to the robo-vocals, some of which are genuinely inhuman, generated by vintage computer chip means. These artificial intelligences are not servants to humans, they’re a potential threat.Likewise, the basslines are given a sympathetically grimy exterior. The cold keys infuse the songs with an often bland commerciality. The tempo is usually faster than most of Kraftwerk’s old output.Nachtfahrt is sung in German, its chord progressions delivering the anticipated transitions. The vocodering is extreme for International Velvet, a cheesy platter, flutey sounds flitting over sterile orchestrations. “I wish I could remix my life to another beat,” Bartos pronounces on the lightweight bounce of Without a Trace of Emotion.The oscillating spiral of The Binary Code provides a brief minimalist abstraction, swiftly followed by Musica Ex Machina, the most mechanical tune on the album, and also the catchiest.The Tuning of the World is one of the best titles, but also the weakest song on board. Rhythmus has a pulverising beat, sounding the closest to the old Kraftwerk template, choral backing kicking in at its climax.The results of this archive-trawl are just what a Kraftwerk disciple would expect – although on certain songs Bartos becomes even more hook-attuned than his old band, taking that tack a bit too far. It’s a mixed manifestation of electronic pop.