This is a demo of Peff using Reason 4.0 to control an Oberheim S.E.M. with CV and gate signals:

I had Reason sending Note CV and Gate CV signals out through the MOTU 896 into an old Oberheim CPS-1 / S.E.M. module. A bit of tweaking was required to get the note cv scaling set, but after finding the right settings, I had Thor acting as a MIDI to CV converter.

With this Thor patch, it’s possible to control analog synthesizer systems (in this case the Oberheim S.E.M.) from the Reason MIDI Sequencer, Thor Pattern Sequencer, Matrix Pattern Sequencer, any LFO source in Reason, and the RPG-8 Monophonic Arpeggiator. It should also be noted that because the Reason 4.0 sequencer is sample accurate, theoretically, the synchronization should be very solid when sending CV signals through the MOTU audio interface.

via PeffTV:

http://www.peff.com/journal/2009/06/12/reason-cvgate-to-analog-synths/ Reason CV signals converted to audio signals via the THOR Polysonic Synthesizer, will send a DC voltage through the Mark of the Unicorn 896 HD audio interface.

In this manner Reason 4.0 can be used to control a variety of analog synthesizers that comply to the traditional CV/Gate voltage protocols. I tested this configuration with the ARP2600, which also works very well.