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"These units are rare as only roughly 600 were made over a decade ago. Here is some more info about the unit:
'The 777 is a monophonic analog synthesizer with a digital sequencer. Built with the highest quality of components, the 777 is housed in a rugged aluminum chassis, has solid cherry end pieces, with top of the line knobs, switches, and electrical components. This machine is built to last.

The 777 is capable of reproducing the oh-so-famous sound of the TB-303 in every way, but that's the least of it. TheTB-303 has only six knobs and one switch to control the sound, while the 777 has all these, plus five times more. There are 32 knobs and 7 switches to be exact, all instantly available with their single dedicated feature. The sequencer part of the synthesizer contains 28 illuminated keys, keeping all the features readily available for the user to tweak at any time. No menus, no virtual analog synthesis--this is the real thing!