Oberheim 6 SEM

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Details:
"6 Oberheim SEM (Synthesizer Expander Modules) and an 8-voice programmer. The programmer and 5 SEMs live in a custom walnut burl wood cabinet and the other SEM is in a stock Oberheim single SEM cabinet. There is an umbilical cable with a cinch jones connector on the single SEM that connects to the main cabinet, and a separate power cable for it (two cables on the single unit). The main cabinet has a power cable and connections for a non-working E-mu non-velocity sequencer keyboard, and the E-mu main cabinet. This sale is contingent on sale of the whole system as that sale takes precedence over the items listed separately.

This synthesizer is not something that you can buy, take home, plug in, and start playing on, unfortunately. But for those who know about these things, it is a very good sounding synthesizer system. The system was designed by Tom Oberheim, but the programmer was designed by his chief engineer at the time, Jim Cooper. Jim did what could be done at this time, but shortly after this, a lot more could be done (like the Prophet 5). So the programmer is more a historical oddity rather than something you might want to use. The two extra voices of programmer were connected to the E-mu main cabinet, and I know one of the programmable envelope generators for that part is no good. These were custom made chips and probably you won't find one. But the ones for the 6 SEMs were working the last time I tried them.

There have been some important modifications to the SEMs. I replaced the 3 op amps in the filter with TL072 chips, the main output chip with a 5532, and the control voltage summing amp with a Burr Brown OPA 21EZ. This made the tuning a lot more stable, and the sound a lot more open with lower noise. Since these synthesizers have a wonderfully buzzy character, these modifications enhanced the clarity of that sound. If you really like these synthesizers, you will not be dissappointed. There is also an 8 channel mixer (at the top in back) with 8 input controls and two output jacks. The stereo spread is fixed so that the pan goes from one side to the other as you march through the SEMs, although none is hard to one side. This mixer is made with 5534 op amps. There are two Oberheim power supplies (plenty of power) and a plus 5 volt supply that was for the keyboard (has no use now).

The shipping weight is 50 lbs for the main and 8 lbs for the separate cabinet."

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