[sdiy] OBX-a Poly mod

[brianw]

Agreed.

If there is a schematic for any poly-mod, each OBX-a voice would require a VCA for mod depth, and a couple of analog switches to choose between filter envelope and OSC2 sources, plus some more analog switches to choose the destinations. Not only would the VCA need a dedicated CV in the patch, but those switches would need a few bits of storage to select the modulation path in each voice.

Brian


On Oct 2, 2025, at 6:36 PM, Michael E Caloroso wrote:
> I have never heard of an OB-Xa mod that adds P5-style polymod.  Frankly it would be useless unless a new programmable CV for mod depth can be implemented.
> 
> MC
> 
> On Thu, Oct 2, 2025 at 3:14 PM ulfur hansson wrote:
>> i came across this matrix-synth post that features images of an obx-a fitted with a mysterious JL-Cooper mod, allowing for prophet-5 style poly-mod.
>> 
>> does anyone happen to have any information on the kits design?
>> 
>> ...or if i should end up feeling brave and design a board to achieve something similar - any thoughts?
>> 
>> thanks y'all!
>> sincerely,
>> -úlfur