Oberheim OB-1

images via this auction

via brian c who has the following to say: "do you know the difference between the grey top and black top knobs?

the grey knobs are available to tweek from inside one of the eight stored patches. the black ones only work in 'manual mode,' when you save a patch their settings are stored with the patch, when you call a patch they are disabled , kinda wierd but that's how it works"