via this auction
Pics of the inside below.
"This is a Oberheim OB-SX 6 voice analog synthesizer. It has been well kept. All the keys, knobs, switches and buttons work. The unit tunes fine when the "Auto" button is pressed. All oscillators work as they should. All of the keys are very quiet and have nice action. The inside is immaculate. The outside case has some scratches and chips on the hood, the underside has longer scratches. Please review all the pictures before purchasing or making an offer. The unit is very deep, about 20", I had to customize my keyboard rack.· This is a super rare, from the factory 56 patch (switchless), 6 voice late production version – voice cards are the 4 pin variety and are dated: “Nov 04 1981”
· Coming from the factory with 6 voice cards: if you know your history of these beauties you know that most of them came with 4 voices standard and then later moved to 5 voices standard to better compete with the Prophet 5. There were a significantly lower number of factory 6 voice versions produced, and it's almost impossible to find a spare voice card if you don't get the 6 voice version.
· Has had a full power supply rebuild within the last 3 years, modern capacitors & rectifiers with better specs than the OEM 1981 designs.
· Several other internal items were replaced along with the power supply, including: dip switch selector for the voice boards and *ALL* of the potentiometers on *ALL* the voice cards have been upgraded to the multi turn, “box” style as opposed to the original single turn “dial” type potentiometers. Huge difference in calibrating and holding precise values - ALL 6 VOICES TUNE.
Most of the Oberheim classic sounds are factory presets in this fabulous instrument. It will ship with a power cord. The unit should warm up for about 15-30 minutes before use even though it tunes fine at first power up."
