megavoice wrote: But the problem is VCOs must be heated up to keep them stable and in greater numbers this has an effect to the price. This is not the case for DCOs.
Not all VCO designs need to be heated.
Many (if not most) VCO designs are not.
But it is true that they must have some sort of autotune or feedback circuit to keep them stable when used in a polyphonic structure.
DCOs don't need such circuits or techniques as above, but have their own share of problems.
Some use a master clock which renders all DCOs perfectly in phase.
Most also don't allow "easy" modulation.
That is, one can't just "plug in" a modulation source (env, lfo, noise, etc) and have the DCO follow along.
Those sources must either be generated or digitally encoded first, then applied to the digital stream controlling the DCO.
Modulation frequencies are therefore limited to the speed and resolution of the digital processing.
So a design that uses VCOs could add a modulation control with something as simple as a pot and resistor, whether originally manufactured that way or modded.
On a DCO design, it could require considerable software changes.
This is one of the big reasons you don't see modular synths that use DCOs.
As for Moog making one, give them time. One day they might.

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