Názor k článku SID: minulost, současnost a budoucnost od prophet - Ako vravi v interview sam autor: The Filter was...

Ako vravi v interview sam autor:

The Filter was a classic multi-mode (state variable) VCF design. There was no way to create a variable transconductance amplifier in our NMOS process, so I simply used FETs as voltage-controlled resistors to control the cutoff frequency.

The filter is the worst part of SID because I could not create high-gain op-amps in NMOS, which were essential to a resonant filter. In addition, the resistance of the FETs varied considerably with processing, so different lots of SID chips had different cutoff frequency characteristics. I knew it wouldn't work very well, but it was better than nothing and I didn't have time to make it better.

Mimochodom, jeho dalsie chipy uz v Ensoniqu (DOC1 - ak si niekto pamata este Ensoniq Mirage, prvy "ludovy" sampler, napr. klavirove solo v Po schodoch/Banket je Mirage) nemali so SID nic spolocne..

Phase accumulating oscilator (pouzity v SID) bol zakladom PPG Wave, prveho wavetable synthu, pravda s analogovym SSM filtrom a VCA..