I've bought a grey (old series) EBS OctaBass, but it's broken (I already knew that). The potentiometers and knobs are missing, but I don't know if that's the only thing that's not working. It didn't cost me much, so I'm prepared to invest a bit in it. Does anyone know what kind of pots EBS used in the old OctaBasses? And if there's a possibility of buying original knobs for an EBS pedal somewhere? Ebay maybe?