Two Voice Pro Synthesizer

People often ask me: "Tom, what was the favorite one of your synthesizers from before?" And my answer is always: "the Two Voice"!

I am introducing, for scheduled delivery in June 2012, the "tom oberheim" Two Voice Pro Synthesizer. It is similar to the original from 1975, but with some very interesting upgrades.



Keyboard Electronics and Mini-Sequencer. (Click for big picture.)


  • Mini-Sequencer is enhanced - you still generate a sequence with the knobs ( up to 16 positions ) but you can store sequences from the knobs into flash memory (up to 99 sequences stored)
  • Two sequences can be played simultaneously (or play one sequence while also playing on the keyboard, like the old one)
  • After sequences are stored in flash memory, you can edit them to add 2-way, 3-way or 4-way ratcheting and you can program the gate length from zero (like a rest) up to almost the complete step length
  • Sequences can be chained into songs, and each step in a song can be programmed for sequence number, transpose amount and number of repeats
  • Sequencer syncs to Midi Clock
  • Keyboard outputs velocity and pressure
  • Each module (both SEMs, Mini-Sequencer, Keyboard Control) has mini-jack patch points (over 50 patchpoints)
  • Pitch and Modulation wheels
  • Pan pots
  • Headphone output
  • Separate Vibrato LFO

The U.S. price of the new Two Voice Pro is $3495

SEM Modules


SEM-PRO combines MIDI to CV with patchpanel. (Click for big picture.)


SEM with analog patchpanel.
(Click for big picture.)


SEM with MIDI to CV Converter.
(Click for big picture.)

There are three versions of the Synthesizer Expander Modules:

1) SEM-PRO. SEM with MIDI to CV Converter and integrated Patchpanel. This version combines the features of the MIDI to CV version (see below) with a 21-jack patchpanel and is personally autographed by me.

  • 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 $1199.


2) 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.


3) 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.

The U. S. price is $999.

Son Of 4 Voice Polyphonic Synthesizer:

SO4V unit at right,
Programmer Panel, above.
(Click for big pictures.)



The response to my earlier announcement of the Son of 4 Voice has been totally overwhelming and gatifying to me. Thanks to all of you who have shown an interest in the SO4V. However, it has caught me completely off guard from a production point of view, so I have decided to delay introduction of the SO4V until later this year. In addition to allowing me to get production organized, I am using the time to add a few much-requested features, such as enhancement of the Programmer section and also the inclusion of a complete set of patchpoints.

I am still 100% committed to bringing the SO4V to market, and I am expecting that this will happen sometime in the latter half of 2012.

Here are some of the features of the Son of 4 Voice:

  • Four classic Synthesizer Expander Module (SEM) synth modules
  • SEMs are 100% discrete analog - no custom chips
  • New state of the art Voice Control & Programmer retains all features of the original Four Voice Programmer and Keyboard control modules while adding new capabilities
  • SO4V may be used as a four-voice polyphonic synthesizer or as four individual synthesizers under MIDI control
  • Two MIDI sync capable LFOs with multiple waveshapes including sample and hold per voice
  • Two programmable ADSR envelope generators per voice
  • Selectable master tuning (both VCOs or VCO2 only) allows easy detuning for huge unison sounds
  • Polyphonic portamento with linear or exponential response
  • Noise generator connected to filter input #1
  • External audio or A440 tuning reference connected to filter input #2
  • Updated output module with mix and pan control for each voice
  • Two SO4Vs can be easily connected together - result: eight voices!
  • Signature plate--each SO4V comes with Tom Oberheim's signature on the front

U.S. Price: To Be Determined



The combination of the SEM's limited programmability, combined with programmable envelope generators and LFOs in the new Programmer, allows many but not all of the SO4V's parameters to be remembered in memory patch storage.

The most important parameters that remain non-programmable in the new Son Of 4 Voice are resonance, filter modes, and initial pulse width.

This was the same situation with the original 4-Voice, and while certain parameters remain non-programmable, enhanced features of the new Programmer add capabilities that the old 4 Voice did not have, programmable or not. Also, the patch storage in the new Programmer is four-way multitimbral, so you can have a different setup stored for each SEM in a patch.

There is also a complete MIDI implementation in the SO4V, including LFO sync to MIDI clock and individual MIDI access to each SEM voice. And the patch storage includes the settings on the enhanced Keyboard Electronics / Voice Assignment section.

The SO4V is a special machine - for ease of use and fast setup, it is outdone by numerous hardware and software synths conceived for the mainstream. But there is nothing on the planet that SOUNDS like it!










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- Tom Oberheim