I finally managed to find a Jupiter 4 after months of wanting one.
However, a day or so after getting it home, I noticed some continuous unwanted noise when ever the key is pressed. I would like to emphasize that of course the noise switch is off. This is really irritating gritty noise which I know for a fact shouldn't be there. The noise is also there when pressing a key with the waveform switched off.
It kind of reminds me of that mechanical vinyl sound - sizzling, crackling, dusty. If anything it has got worse and over powers the sound if the LPF is open. The noise is also there if the 'hold' button is engaged after pressing a key. However, there is no idle noise on the outputs which seem fine. A few of the presets (especially ones which close down the LPF such as bass) sound betterish - even though you can still hear the noise mixed in.
Trying to isolate the problem before spending any more money; it already emptied my savings