String changing mystery on Ibanez EHB

[Spingere]

I recently changed the strings on my lovely Ibanez EHB 1265ms.

 

I put in DR Dragon Skin+ Nickels. I bent the strings before cutting off the excess and was all ready for a final tune up when I spotted the A string unwinding.

 

All the other string were fine, so I assumed it was a fault with the string. A replacement was sent and, you guessed it, the same thing happened.

 

Any ideas for what I'm doing wrong, given that all the other strings are still fine?

Edited 16 hours ago by Spingere
Typo

[itu]

It seems that the core is round. If you are not careful when cutting it and then with installation, the winding may loosen. 

 

Hexagonal core keeps the winding better in place. 

[Spingere]

I was wondering about that. I've ordered some hex core D'addarios. But still, I must have been lucky with the other four strings.

[Mokl]

It is weird! I was going to say that with round core especially, make sure you've got a nice strong bend in the string before cutting so the core can't 'slip', but it's odd that the others were ok, suggesting you'd likely done that. Don't want to teach you to suck eggs etc

Edited 6 hours ago by Mokl

[fretmeister]

I've used roundcores on that type of bass.

 

I found the secret with a headless and round cores is to put a Z bend in the string after it has gone through the head string clamp - but before it is actually clamped.

Just a hard left and right bend is enough to stop it unravelling and then clamp it. Doesn't have to be a long Z - just do the bends as close to each other as you can with pliers. That gives the wrap something to bind on.

 

When cutting the excess off leave the Z bend alone so it's always there. With the effect of the Z and the clamp you can even then take the strings off and put them on again later without them unravelling.