[andrep]

have tried several types of DIY power cables, namely with ground sleeve and solid 2,5cm2wire in several winding formulas.

Cant say I could detect much difference between solid and multistrand cables, then again it was before my new studio speakers.

 

[tonyvdb]

the real difference is simply the fact that solid has a little more resistance and is harder to pull and bend.

 

[andrep]

so, if the lenght is kept short, will the extra area have an audible effect?

 

[tcarcio]

I don't think you can hear any difference in short lengths of wire of the same gauge and it is really just a handling difference as Tony said. I would use solid inside a wall but that would be it.