MS-50 filter

[Martin Czech]

Sorry, again, the last attempt was crippled somewhow...


> I had a look at the MS-50 VCF/VCA schematics at Music Machines.
> Here are a couple of questions for those in the know:
> Do the diodes in the CA3019 need to be thermally coupled? Or can the CA3019 be replaced by matched 1N4148s?
> Two 100k resistors in the VCA are corcled. Does that mean that the should be matched? Or something else?
> What control characteristic does this filter have? 1 V/oct or something else?
> Is the VCA linear or exponential?
> 
> /Jorgen

Once upon a time a made a short analysis of that FILTER

Should be in the archive.

Diode matching: Yes, that's why CA3019

DIY: match diode voltages for the smallest and the largest current.
Similar to Moog ckt.

Thermal coupling is also good. 1N4148 + Epoxy ?


The op amps drive voltage into diodes-> expo current.
thus allmost expo characteristic.


m.c.