News from Plan B:
The Plan B Model 15 Rev.2 will begin shipping on May 6, 2007. The circuit is identical to previous releases with the addition of a new connector to support the 15A Expander. This is the only circuit change. To facilitate this the PCB had to be redesigned and while we were at it we reconfigured that assembly to mount parallel to the faceplate, taking the overall depth of the module from 4.25 inches to just over 1 inch thick. click for photo.
The new 15A Expander adds functionality to the M15 and a direct result of customer requests. It connects to the Rev.2 VCO via a dedicated I/O connector located on the back of the PCB. It can however be retrofitted to any Model 15's regardless of revision, although earlier releases (rev 1 - 1.6) will require point-to point connections. the 15A is only 4 HP wide and adds a PWM attenuation pot, a Soft/Hard Sync crossfade pot (which amplifies the M15 sync function up to x4 it's previous intensity), 3 three way transposition switch (configured octave up/none/octave down) and two additional 1V/oct VC inputs. The 15A will begin shipping at the end of May 2007 with a retail price of $70.
While this 'fixes' the two things I wasn't thrilled about with the Model 15 (the lack of octave switch never bothered me at all, in fact, I'd prefer it not be there), I think I'm still sold on 2 Livewire oscs. With the new Model 15 + 15A expander, that's 22HP, only 6HP less than the Livewire osc, so I'm not really saving that much space by sacrificing functionality of the Livewire (animated saw/pulse, dedicated sub osc out, independent square and pulse outs, dedicated sync source out, etc).
PS. Looks like it was also covered here on Matrixsynth.