Oberheim Synthesizer Expander Module (SEM) Now Available

More than thirty five years after it first appeared on the musical landscape, the unique voice of the Tom Oberheim Synthesizer Expander Module (SEM) will sing again.

Electronic musical instrument pioneer Tom Oberheim is officially reintroducing the SEM in three configurations, each of which is true to the analog design characteristics that were at the heart of the original device.

Musicians familiar with the layout of the original SEM will feel right at home operating the new units; with only minor hardware alterations, due to non-availability of certain components, the instruments are virtually the same as the first units that shipped out the factory door.

The three SEMs include:

  • a model with a thirty-three point “CV-Gate” patch panel;
  • one with MIDI-to-CV conversion circuitry; and
  • an SEM-PRO model incorporating twenty-one patch points along the top rail in addition to MIDI-to-CV capabilities.

Tom Oberheim points to a decline in the uniqueness in the sonic characteristics of commercially available synthesizers over the years as one of the reasons he decided to undertake the resurrection of the SEM.

‘What happened in the eighties and nineties is that synthesizers became so perfected that they just lost their ‘edge,’ says Oberheim. ‘The old stuff has some real individualistic qualities.’

Tom plans to build these units by hand at his shop in California and will personally sign each of the SEM – PRO units.

Prices are $899 for the SEM Patch Panel and MIDI-to-CV models and $1,199 for the SEM-PRO.

Sales are being handled by Geoff Farr of GSF Agency at 310-995-0100, or by email at geoff at gsfagency.com.

Here are details on the new SEM synthesizers:

SEM-PRO. SEM with MIDI to CV Converter and integrated Patch panel. This version combines the features of the MIDI to CV version (see below) with a 21-jack patchpanel and is personally autographed by me. The U.S. price is $1199.

SEM with Patchpanel. All internal SEM connections are brought out to 3.5mm minijacks – all 33 of them. The basic connections are a one-volt-per-octave VCO control voltage and a standard 0 to +5 volt gate signal. On this version of the SEM, there is no MIDI input. The U.S. price is $899.

SEM with MIDI to CV Converter. This version includes a high precision MIDI to CV Converter that has been specifically designed to allow MIDI to control the SEM, and has additional features that make use of the SEM’s external inputs. Some of the features of the MIDI to CV Converter are:

  • Select MIDI channel, controller number and bend range
  • Select note assignment modes: latest, high note and low note priorities
  • Select note re-trigger, filter track, LFO reset
  • A second independent control bus allows velocity, controller data, or channel pressure to modulate either or both VCOs, the filter and the VCA
  • Transpose function allows different keyboard controllers to utilize the complete MIDI note range
  • Analog portamento
  • Input preamp gain control – allows an external audio input to be processed thru the SEM
  • High precision A-440 Hz tune signal
  • Control voltages and gate are bought out to rear panel connectors so MIDI to CV function can be used with other CV/Gate gear.

The U. S. price is $899.

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