4052N broken. how? [SOLVED]

I was dusting off my old AMBIKA the other night and found that one of the SVF Voicecards just gives me a weird distorted Sound in LP-mode. HP and BP work fine. After reheating the not so good looking solderjoints with no effect i tried swapping ICs. With another 4052N everything works fine.
So, getting a new one isn’t the problem, but i’m wondering what could have caused the IC to break? I have to say that the Synth has no enclosure but i took good care and it was in a safe spot on the desk.
Thanks

Which reference of 4052 is it? Maybe you ran into the same problem as hpsound - using a part rated for +/- 5V only?

Yes. that seems to be the problem. I ordered the part that used to be in the reichelt-bom and thats +/- 5v.
Excellent support, as always. Thanks