There are issues with the analogue aspects of the SID. No problem with the digital, but the oscillators, filters etc rely on imperfections of the silicon manuf

There are issues with the analogue aspects of the SID. No problem with the digital, but the oscillators, filters etc rely on imperfections of the silicon manufacturing process back in the day. I'm given to understanding that they weren't so much designed as were just "there" and exploited to make sounds. This is evident in how different generations of SID sound slightly different.