Oscillator one of the fifth voice on my polybrute was defective. It did work properly at first, but after a couple months it started to act up. After a 10-15 minutes warm up it started to output only very low frequency rumble. I sent my unit back for repair. First Arturia's repair partner in Germany had it for three weeks, but they had to sent it to France to Arturia as they couldn't fix it. After Arturia had it over two weeks without being able to fix it either, I asked for a refund.