I just bought a hofner ignition Se bass. It seemed OK. I adjusted the bridge for correct intonation and got it in tune. Then I decided to change the strings for flat wounds as it comes with roundwounds and every place I've read they advise Flatwound. So I purchased Hofners own brand flat wound contemporary bass strings 40,60,75,95. These work out cheaper than LA Belle at £60 a pack and I heard these were just as good being hofner brand. Here is where the troubles began. No matter what I tried I could not get the bass in tune. I spent all day adjusting the bridge as it buzzed at certain frets and even though I got the intonation set it would be out of tune on different strings at different parts of the neck. I adjusted the truss rod and even adjusted the pickup height as it had awful overtones up the neck. It would sound like a tone with another tone slightly detuned. Adjusting the pickup height seemed to reduce this a lot but it was still there. However the main bug bear was not being able to tune it. In the end after much frustration I took off the flat wounds and put back the original strings. Bingo I could get it back in tune again. This puzzles me though. Why would another set of strings cause this? Everywhere I've read of people advising and swapping for flat wound yet this bass doesn't seem to like them. Am I doing something wrong? Is it the bass at fault? Is it a bad set of strings? If anyone has an answer or experienced the same thing I would love to hear about it.