The dual VCA looks like a good building block for my current summing console. One of these per channel to perform fader/pan function (perhaps with selectable pan law).
The 3 pf that each VCA would present to the bus would add up across a large number of channels but using a variant on a MFB LPF in summing amp could easily tolerate that capacitance and more.
I always liked the idea of a large summing structure with no noise gain in the bus In fact with no noise gain on the summing amp, a VCA could be used there too for almost unlimited bus headroom (headroom would be the reciprocal of VCA cut capability). Of course then the MFB filter is out and the bus capacitance might degrade stability of summing VCA. I have some ideas but they would require melting some solder to confirm.
The beauty of using VCAs per channal is you wouldn't need to physically put a VCA on the master to apply global gain changes. Applying a gain offset to every channel VCA could give you a virtual bus VCA.
This might be commercially viable if this trend in mixing digital projects with analog mixers had some basis in theory and therefore legs. If it does, that basis escapes me.
JR
The 3 pf that each VCA would present to the bus would add up across a large number of channels but using a variant on a MFB LPF in summing amp could easily tolerate that capacitance and more.
I always liked the idea of a large summing structure with no noise gain in the bus In fact with no noise gain on the summing amp, a VCA could be used there too for almost unlimited bus headroom (headroom would be the reciprocal of VCA cut capability). Of course then the MFB filter is out and the bus capacitance might degrade stability of summing VCA. I have some ideas but they would require melting some solder to confirm.
The beauty of using VCAs per channal is you wouldn't need to physically put a VCA on the master to apply global gain changes. Applying a gain offset to every channel VCA could give you a virtual bus VCA.
This might be commercially viable if this trend in mixing digital projects with analog mixers had some basis in theory and therefore legs. If it does, that basis escapes me.
JR